METHODS FOR EPIDEMIOLOGY & RESEARCH
KNOWLEDGE BASED COMPETENCIES AND METHODS
COMPETENCIES
METHODS
1.
Listing of epidemiological techniques and methods
Lecture, Review of Research Articles .
2.
Describing application of these methods to communicable and noncommunicable diseases in community and hospital situation
3.
Apply biostatistical method and technique
4.
Deciding when there is epidemic
5.
Method of surveillance
6.
Steps of investigation of an epidemic
7.
Steps Of Designing any Research activity
Project work in Community and Hospital.
Lecture, Practical and Project work.
visit to District health office and record section
Lecture and visit to PHC
Case Study
Project work and lecture
SKILL BASED COMPETENCIES AND METHODS
1.
Use epidemiology as a scientific tool to make rational decision relevant
to community & individual patient intervention
2.
Collect , analyse , interpret & present simple community & hospital
based data.
3.
Investigation of epidemic.
4.
Designing study to test hypothesis
5.
Applying appropriate statistical method to test the significance of
association
6.
Writing research article /report.
7.
Method for reviewing research article.
8.
To keep track of the disease in the community & to decide the action if
warranted at PHC level.
Case Study And Project Work
Project Work
Case Study
Lecture and Case Study
Project work
Project work, Article review
Journal presentation and discussion
Lecture and Case study
AN EXAMPLE… INVESTIGATION OF AN OUT BREAK.
1.
Defining Epidemic
Lecture ,Review of Research articles
2.
Listing types of epidemic
3.
Deciding when there is epidemic
4.
Method of surviellence
5.
Steps of investigation of an epidemic
Case Study
6.
Prevalence and incidence of endemic diseases
Visit to PHC
7.
Demography of the area of concern
8.
Reference laboratories available for Virus/Bacterial Culture
9.
Collect , analyse , interpret & present data related to out break
Project work in community and hospital
visit to district health office and record section
Lecture and visit to PHC
Lecture
Visit to PHC/CHC/District hospital
10. Applying appropriate statistical method to test the significance of
association.
1
Project Work
Project Work
CONTENTS
SECTIONS
Topics
SECTION - A
Epidemiological methods and techniques
SECTION - B
Surveillance- methods use and example
SECTION - C
Outbreak investigation
SECTION - D
Designing a research activity
ANNEXURES
 OUTBREAK INVESTIGATION
(Trigger & Response Mechanisms)
In IDSP
 IDSP forms and surveillance
guidelines
 Writing reports/ articles
 Reviewing a research article
 Exercise on understanding
community
 Exercise Community Involvement
and Communication
 Exercise on supportive supervision
2
SECTION – A
Epidemiological methods and
techniques
3
Epidemiology module of practical skills
Learning Objective



The student should be able to know the relevance & importance of applying
epidemiological skills to bring out effectiveness as a basic doctor in Rural e.g. PHC& other
urban settings .
Student should be able to understand the implication of epidemiological principles in
various National Health Programmes.
Use epidemiology as a scientific tool to make rational decision relevant to community &
individual patient intervention
When should s are going to field visits he/she should be able to do Measurement of morbidity ,
mortality , Incidence & prevalence from existing data of recent outbreaks in community provided
by the health centre authorities.
Epidemiology Defined
"The study of the distribution and determinants of health-related states in
specified populations, and the application of this study to control health
problems."
A look at the key words will help illuminate the meaning:

Study—Epidemiology is the basic science of public health. It's a highly quantitative discipline based on
principles of statistics and research methodologies.

Distribution—Epidemiologists study the distribution of frequencies and patterns of health events within
groups in a population. To do this, they use descriptive epidemiology, which characterizes health events in
terms of time, place, and person.

Determinants—Epidemiologists

Health-related states—Although
also attempt to search for causes or factors that are
associated with increased risk or probability of disease. This type of epidemiology, where
we move from questions of "who," "what," "where," and "when" and start trying to answer
"how" and "why," is referred to as analytical epidemiology.
infectious diseases were clearly the focus of much of the early
epidemiological work, this is no longer true. Epidemiology as it is practiced today is applied
to the whole spectrum of health-related events, which includes chronic disease,
environmental problems, behavioral problems, and injuries in addition to infectious disease.
4

Populations—One

Control—Finally,
of the most important distinguishing characteristics of epidemiology is that
it deals with groups of people rather than with individual patients.
although epidemiology can be used simply as an analytical tool for studying
diseases and their determinants, it serves a more active role. Epidemiological data steers
public health decision making and aids in developing and evaluating interventions to control
and prevent health problems. This is the primary function of applied, or field, epidemiology.
A comparison between the practice of public health and the more familiar practice of health
care helps in describing epidemiology.
First, where health care practitioners collect data on an individual patient by taking a
medical history and conducting a physical exam, epidemiologists collect data about an
entire population through surveillance systems or descriptive epidemiological studies.
The health care practitioner uses his or her data to make a differential diagnosis. The
epidemiologist's data is used to generate hypotheses about the relationships between
exposure and disease.
Both disciplines then test the hypotheses, the health care practitioner by conducting
additional diagnostic studies or tests, the epidemiologist by conducting analytical studies
such as cohort or case-control studies.
The final step is to take action. The health care practitioner prescribes medical treatment,
and the epidemiologist, some form of community intervention to end the health problem
and prevent its recurrence.
One succinct way to sum up the task of epidemiologists is to say that they "count things."
Basically, epidemiologists count cases of disease or injury, define the affected population,
and then compute rates of disease or injury in that population. Then they compare these
rates with those found in other populations and make inferences regarding the patterns of
disease to determine whether a problem exists,. For example, in the hepatitis B example earlier, you might
ask: Is the rate of disease among people with no know risk factors greater than we would expect? Is the
pattern or distribution of the cases suspicious? Once a problem has been identified, the data are used to
determine the cause of the health problem; the modes of transmission; any factors that are related to
susceptibility, exposure, or risk; and any potential environmental determinants.
5
For this students should be aware of basics of epidemiology in terms of
I.
MEASUREMENT OF FREQUENCIES
II.
CONCEPT OF NUMERATOR AND DENOMINATOR
III.
MEASURES OF CENTRAL TENDENCY
IV.
MEASURES OF DISPERSION
V.
MEASUREMENTS OF MORBIDITY
VI.
MEASUREMENT OF MORTALITY
VII.
MEASUREMENTS OF FERTILITY
VIII.
MEASUREMENTS OF DISABILITY
I.
MEASUREMENTS OF FREQUENCIES:
Rate, Ratio, and Proportions
i. Rate:
The rate is the occurrence of a particular event in a population during a given time period.
Example: Crude Death Rate
No. of deaths in one year
Death rate= _____________________ X 1000
Mid- year population
e.g., 24 deaths occurred in a village having mid-year population of 4000
Calculation:
Death rate in that village = 24X1000/4000=6 per 1000 population
Note: Rate comprises the following elements- numerator, denominator, time specification and
multiplier. The time dimension is usually a calendar year. The rate is expressed per 1000 or some
other round figure selected according to the convenience or convention, to avoid fractions.
Types
a. Crude Rates: birth and death rates. These are un-standardized rates.
b. Specific rates: disease specific, age and sex specific, time specific.
c. Standardized rates: these are obtained by direct or indirect method of standardization or
adjustment e.g. age and sex standardized rates.
6
ii. Ratio:
It expresses a relation in size between two random quantities. The numerator is not a component
of denominator. The numerator and denominator may involve an interval of time or may be
instantaneous in time. Broadly, ratio is the result of dividing one quantity by another. It is
expressed in the form of x: y, e.g. sex ratio, doctor-population ratio, child-woman ratio, etc.
Say sex ratio is 933: 1000.
iii. Proportion:
is a ratio, which indicates the relation in magnitude, of a part to the whole. The numerator is
always included in the denominator. It is usually expressed in percentage, e.g. percent of under five
children suffering from malnutrition of the total under five populations. Say a proportion of 60% of
the under five children is suffering from malnutrition.
Exercises and Solutions
Rates and Percent Distributions
Exercise A
The following are data for two counties:
Recall the formulas for the crude birth and fertility rates:
For each of the counties, calculate the following:
1. the crude birth rate
2. the crude fertility rate
3. the fertility rate for adolescents aged 10-17
4. the percent of total births to adolescents aged 10-17
Do either County X or County Y have an excess of adolescent births? Which county is in more need
of programs targeted at the adolescent population?
SOLUTION:
Rates and Percent Distributions
Solution for Exercise A
7
County Y has a higher % births to adolescents than County X, but a lower adolescent fertility rate.
This is because the adult women in County Y have a lower fertility rate than the adult women in
County X resulting in the lower overall birth and fertility rates seen in the above table for County Y.
The elevated %births to adolescents in County Y compared to County X, therefore, is due to these
differences in the rates for the adult women.
The % births to adolescents are not a rate because adult women who are no longer at risk of
delivering in their teen years are included in the denominator. It can be argued that the adolescent
fertility rates are a “fairer" comparison of the two counties since they are based solely on the
experience of their adolescent populations, unrelated to the experience of other women. On the
other hand, some might argue for using% births to adolescents precisely because it reflects the
experience of teenage women in relation to the overall fertility behaviour in their communities.
Defining excess adolescent fertility must be based on a community standard. It may be that any
adolescent childbearing is considered an excess, or this may be determined in relation to a state or
National average or goal.
II.
CONCEPT OF NUMERATOR AND DENOMINATOR:
For calculation of rate, ratio or proportion proper understanding of the Concept of Numerator and
Denominator is very important.
a. Numerator: Numerator refers to the number of times an event (e.g. number of birth) has
occurred in a population, during a specified time period.
b. Denominator: Numerator has little meaning unless it is related to the denominator. The
epidemiologist has to choose an appropriate denominator while calculating a rate. It may be
related to: (I) population (II) the total events.
(I) Denominator related to the population:
(i)
(ii)
Mid year population: Because the population size changes daily due to births, deaths and
migration, the mid year population is commonly chosen as a denominator. The population
as on 1st July is mid-year population.
Population at risk: It is important to note that the calculation of measures of disease
frequency depends on correct estimates of the numbers of people under consideration.
Ideally, these figures should include only those people who are potentially susceptible to
8
the disease studied. For instance, men should not be included in denominator for the
carcinoma of cervix.Part of population, which is susceptible to a disease is called the
population at risk, e.g., Occupational injuries occur only among working people so the
population at risk is the workforce.
Person – time: In some epidemiological studies (e.g. cohort studies), person may enter into
the study at different times. Consequently, they are under observation for varying time
period. In such case, the denominator is a combination of person and time. The most
frequently used person time is person- years. Some times this may be person months,
person weeks or man- hours. For example, if 10 persons were observed in the study for 10
years, person time would be 100 person years of observation. The same figure would be
derived if 100 persons were under observation for one year. These denominators have the
advantage of summarizing the experience of persons with different duration of observation
or exposure.
(iii)
(iv)
Sub groups of the population: the denominator may be subgroups of population e.g.
under-five, female, doctors, etc.
(II)
Denominator related to total events: In some instances, the denominator may be
related to total events instead of the total population, as in the case of infant mortality
rate the denominator is total number of live births.
III.
MEASURES OF CENTRAL TENDENCY
We need to workout averages for large number of values to make some sense. It gives the mental
picture of the central value. There are several kinds of average, of which the commonly used are
arithmetic mean, mode and median. Averages are measures of central value, therefore they locate
the center or mid point of a distributions.
(a) Mean: To obtain the mean the individual observations are added together, and then divided by
the number of observations.
(b) Mode: The mode is the most commonly occurring value in a distribution of data.
(c) Median: To obtain the median, the data is first arranged in a descending and ascending order
the value of middle observation is located, which is called median.
EXERCISE
Calculate mean, mode, and median for hemoglobin values of 20 pregnant women.
12, 10, 8, 9, 12, 10, 7, 9, 7, 10, 11, 8, 12, 7, 8, 13, 11, 9, 10, 11, 7
Mean:
Median:
Mode:
IV MEASURES OF DISPERSION
9
(a) Percentile: Sometime one has to locate other points in the range. This can be done with the
help of percentile. Just as the median divides the subjects in two equal groups each with nearly n/2
subjects, the percentiles divide the subjects in 100 equal parts. Each part is containing n/100
subjects. If n= 400, each part will have 4 subjects. The parts are identified by 99 cut points of the
measurements under consideration. Consider weight to nearest Kg. of 2 yr old 35 boys:
10, 12, 9, 11, 10, 12, 12, 13, 8, 9 13, 14, 13, 8, 9, 11, 11, 10, 12, 13, 9, 12, 10, 11, 14, 9, 12, 12, 13,
12, 9 13, 10, 11, 10,
For example 20ths percentile of weight is that value below which are 20% children, for n=35, then
20% of children mean 7 children. The procedure is to arrange their weights in ascending order and
pick up the seventh value. When arranged in ascending order, there weights in Kg. are:
8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 13, 12, 12, 12,
13, 13, 13, 13, 13, 13, 13, 14, 14
The seventh value is 9 kg. This is the 20th percentile of weight of 2 yr old boys as far as these data
are concerned. Similarly we can find out given percentile by adopting the above procedure. It can
be determined by the formula [kth percentile = (k X n/100)].
(b) Deciles, Quartiles and Tertiles:
Deciles divide the group of subject in to 10 equal parts. Quartiles in to four equal parts and tertiles
into three equal parts. Tertiles are often used to divide the subjects into those with low, medium
and high values.
V MEASUREMENTS OF MORBIDITY
Morbidity data should be accurately and completely collected and transformed into various rates
to make the understanding of magnitude of the health related event meaningful.
i.
Incidence Rate (IR):
It is the number of new events that occurs in a defined time period in a geographical area. The
denominator is the population at risk for that event during that period. The most accurate way of
calculating incidence rate is person-time incidence rate. Each person in the study population
contributes one-person year to the denominator for each year of observations before disease
develops or the person is lost to follow-up.
No. of people who get a disease in a specified period
IR =______________________________________________X 1000
Sum of the length of time during which each person in the
population is at risk.
The incidence rate takes into account the variable time periods during which individuals are
disease free and thus at risk of developing the disease. Since it may not be possible to measure
disease free periods precisely, the denominator is often calculated approximately by multiplying
10
the average size of the study population by the length of the study period. This is reasonably
accurate if the size of the population is stable and I.R. is low. For example, in a sub-center with
population of 5000 there are 5 new cases of tuberculosis occurred during one year. For this disease
the whole population is at risk of tuberculosis, hence the incidence rate of tuberculosis would be 1
per 1000.
EXERCISE
In order to measure the quantum of sickness in children under 5 years of age , a astudy was
conducted among 153 children from May 2004 to April 2005 in Urban area . The five leading cause
of illness of number of person ill and spels of illness is as follows ;
Disease
No of children ill
No. of spell
Common cold
103
169
Diarrhea
62
132
Boils
60
73
Fever
37
42
Conjuctivities
31
37
Calculate
i
Incidence rate(person) for each of the leading cause?
ii
Incidence rates (spells) for each of the leading cuses?
iii
Spells of illness for each disease for each sick child?
Special Incidence Rates:
(a) Attack rate: The attack rate is defined as number of new cases of a specified disease during a
specified time interval per 100 populations at risk during the same time interval. An attack rate is
used only when the population is exposed to risk for a limited period of time such as during an
epidemic.
Formula:
Number of new cases of a specified disease
during a specified time interval
Attack rate = ------------------------------------------------------------ X100
Total population at risk during the same time interval
(b) Secondary attack rate (SAR): is defined as the number of exposed persons developing the
disease within the range of incubation period following exposure to a primary case.
11
Formula:
Number of exposed persons developing the disease
within the range of incubation period
SAR = ------------------------------------------------------------------X 100
Total number of exposed/ susceptible contacts
The denominator consists of all persons who are exposed to case. More specifically, the
denominator may be restricted only to susceptible contacts. The primary case is excluded from
both numerator and denominator.
Example: Suppose there is a family of 6 consisting of 2 parents (already immune) and 4 children
who are susceptible to a specific disease, say measles. There is a primary case and within a short
time 2 secondary cases among the remaining children. The secondary attack rate is 2/3 or 66.6%.
Exercise 1 – During an eight hour work shift at a factory , 30 employee visited the company
physician with the complaints of nausea , vomiting headaches & dizziness.
Q.. If 600 hundred person worked in the factory what is the attack rate of the disease ?
Exercise 2
There was an out break of Typhoid Fever in Pondicherry . Few cases occurred in JIPMER campus
and some from various part of the town . Secondary cases with in 30 days of onset were also
reported .Data are given below ----Typhoid fever in household pondicherry secondary cases in houses with two types of sanitary
facilities .
Household with Privy & Well
Houses with public water supply &
sever system
Age
in
years
No. of contact
No.
exposed
sec.cases
to
of
Attack
No.
rate
contact
primary cases
exposed
of
No
sec.cases
to
primary
cases
0-4
173
41
143
9
5-14
196
37
216
10
15&above
245
24
361
14
12
of
Attack
rate
Total
614
102
720
33
Q1 – Calculate the secondary attack rate in each category.
Q2- What inference do you draw from this result?
ii. Prevalence: The total number of all individuals who have an attribute or disease at a particular
time or during a particular period divided by the populations at risk of having the attribute or
disease at this point of time or midway through the period. Although referred as rate, prevalence
is really a ratio.
Types of Prevalence
a) Point Prevalence: The data have been collected for one point of time. The point in, point
prevalence may for all practical purposes consist of a day, several days or even a few weeks
depending upon the time taken to examine the population sample.
b) Period Prevalence: It measures the frequency of all current cases (Old & New) existing during a
defined period of time (e.g. annual prevalence) expressed in relation to a defined population. It
includes cases arising before but extending into or through the year as well as those cases arising
during the year.
No. of existing cases (old & new) of a specified disease
During a given year (period of time interval)
Prevalence = -------------------------------------------------------------X1000
Estimated mid year (interval) population
iii. Relationship of Incidence with Prevalence
Prevalence depends upon two factors- the incidence and duration of illness
P=IXD
P= Incidence X mean Duration
Prevalence vs. Incidence
Exercise B
In June, 1995, at the end of their senior year, the following observations were made concerning
smoking in a population of 110 graduating seniors. The enrolment for this cohort from 9th to 12th
grade was as follows:
13
9th
10th
11th
12th
Sept. 1991
Sept. 1992
Sept. 1993
Sept. 1994
160
140
120
110
The seniors were asked the following question. “At any time while you were in high school (Sept.
‘91 -June ‘95), did you smoke at least one pack of cigarettes a week? If yes, when did you start and
for how long did you smoke?” Of the 110 graduating seniors surveyed, 20 reported having smoked
at some time during high school. The following table shows the data for these 20 students:
14
Using the data above, answer the following questions:
1. From Sept. 1993 - Aug. 31, 1994 what was the incidence rate of smoking?
2. What was the prevalence of smoking at the time of the survey in June, 1995?
3. The survey was given to the 110 graduating seniors. How valid are the results of the survey
as estimates of smoking incidence and prevalence for the high school age adolescents in
this community?
Prevalence vs. Incidence
Solution for Exercise B
1. Students #4, #9, and #16 begin smoking during this time, and ten other students were
already smoker sand therefore not at risk for becoming smokers, so the incidence rate is 3 /
(110-10) or 3.0 %.
2. Nine students were smoking at the time they graduated high school, for a prevalence rate of
9 / 110 or8.2 %.
3. If smoking behaviour among graduating seniors is the same as that for students who
dropped out, then the results are good estimates. If smoking status is related to drop out
status, then the results may be over or underestimates depending on whether those who finish
high school are more or less likely to smoke than those who do not.
15
Incidence and Prevalence
Exercise C
The County Y Head Start Program enrolled 500 children in the Fall of 1995. All of these children
were screened for vision problems at the beginning of the year and 50 were found to have vision
problems.
When the same 500 children are screened again in the Fall of 1996, 65 are found to have vision
problems.
1. What was the prevalence of vision problems in County Y’s Head Start program in 1995?
2. What was the prevalence of vision problems in County Y’s Head Start program in 1996?
3. What is the risk of developing vision problems between the Fall of 1995 and the Fall of 1996 in
this group of Head Start children?
Solution for Exercise C
1. 50/500 = 10%
2. 65/500 = 13%
3. Risk means incidence; # of new cases/population at risk = 15 = 3.3%
450
Exercise D
The Hospital X Emergency Room in Community A recorded 120 asthma cases during 1995 out of a
total of 1450 individual children seen. The state Children with Special Health Care Needs (CSHCN)
program was interested in determining if these numbers meant an increased risk of a child
developing asthma in Community A or a possible decrease in the effectiveness of the medication
taken by asthmatic children in Community A. In 1996 they asked the hospital to track the number
of first time asthma diagnoses admitted to the ER versus those asthma cases who visited the ER but
had been previously diagnosed as having asthma.
In 1996 out of 1370 children seen in the ER, there were 130 asthma cases: 42 were new cases, 88
had been previously diagnosed prior to the ER visit.
1. What was the risk of having asthma in 1995 for children in Community A seeking ER care at
Hospital X?
2. What was the prevalence of childhood asthma in 1995 in the ER at Hospital X in Community
A?
3. What was the prevalence of childhood asthma in 1996 in the ER at Hospital X in Community
A?
4. Can the state CSHCN program answer its question?
16
5. Does knowing the incidence of childhood asthma diagnoses in the ER at Hospital X in
Community Ain 1996 help? What is the incidence?
6. What else is needed to answer the CSHCN program’s question?
Incidence and Prevalence
Solution for Exercise D
1. Risk refers to incidence data. Since there is no information about new cases for 1995, this
question cannot be answered.
2. 120/1450 = 8.3%
3. 130/1370 = 9.5%
4. No, these two prevalence estimates do not provide any information about the risk of
developing asthma among children in Community A.
5. Knowing the incidence rate helps somewhat but does not tell the entire story as children
seeking care for their asthma in the ER are not representative of the entire population of
children with asthma in Community A. Incidence rate: 42/1282 =3.3%
6. It would be helpful to have baseline information on the incidence rate of childhood asthma
diagnoses in the ER at Hospital X in Community A. Short of obtaining information from
population based child health surveys over time, it would also be important to obtain data
from primary care physicians in the community, other community hospitals, from the
schools, and possibly from the pharmacists in the community. In addition, it might be
helpful to compare Community A's data to data from similar communities
Example: If incidence is 10 cases / 1000 people per year and mean duration of disease is 5 years,
then
Prevalence = 10 X 5 = 50 / 1000 population.
EXERCISE:
In a population of 1000, following are the details of cases of tuberculosis. Calculate incidence, point
prevalence (as on 1st July) and period prevalence for 2001 and comment on it.
Case No
Detected on
Died / Cured on
1
Jan 12, 1999
March 13, 2001
2
Feb 13, 1999
Dec 18, 2000
17
3
April 29, 1999
Not cured upto 31 Dec 2003
4
Oct 23 1999
Sept 23, 2002
5
Feb 12, 2000
Oct 30, 2001
6
April 1, 2000
Sept 21, 2001
7
June 23, 2000
April 1, 2002
8
Feb 24, 2001
May 23, 2002
9
July 11, 2001
July 12, 2003
10
Aug 15, 2001
April 11, 2002
11
Sept 23, 2001
May 9, 2003
12
Nov 21, 2001
Not cured upto 31 Dec 2003
13
April 12, 2002
July 12, 2003
14
June 13, 2002
Sept 23, 2003
15
Oct 3, 2002
Not cured upto 31 Dec 2003
16
Dec 12, 2002
Dec 23, 2003
17
Dec 16, 2002
Sept 1, 2003
18
Feb 12, 2003
Not cured upto 31 Dec 2003
19
Sept 1, 2003
Not cured upto 31 Dec 2003
20
Oct 11, 2003
Not cured upto 31 Dec 2003
VI MEASUREMENTS OF MORTALITY
i
Crude Death Rate
It is defined as “the number of deaths (from all causes) per 1000 estimated mid year population in
one year, in a defined geographical area.
18
No. of deaths during the year
Crude Death Rate = ------------------------------------x 1000
Mid year population
ii
Specific Death Rates: can be specific to age, sex, occupation, diseases, etc.
Disease Specific Mortality:
No. of deaths from specific disease
during a calendar year
Disease Specific = ------------------------------------------------ X 1000
Mortality Rate
Mid year population
Example: In a village with population of 5000 there are 5 deaths due to tuberculosis occurred in a
year. Death rate due to tuberculosis would be 1 per 1000.
Child Mortality
Still Birth Ratio: Defined as “ Death of foetuses weighing 1000 gm (this is equivalent to 28 weeks of
gestations) or more occurring during one year in every 1000 live births.
Foetal deaths weighing 1000gm or more at birth
Still Birth=------------------------------------------------------------- X 1000
Ratio
Total no of live births
Still Birth Rate: Still Birth Rate is defined as number of deaths of foetuses weighing 1000gm or
more occurring during 1 year per 1000 total births (live + still births).
Still
Foetal death weighing 1000gm or more at birth
Birth = --------------------------------------------------------------- X 1000
Rate
Total (live + still) births weighing 1000gm or more at birth
Neonatal Mortality Rate (NMR): NMR is defined as the number of neonatal deaths under 28 days
of age in a given year per 1000 live births in that year
19
No of death of children under 28 days of age in a year
NMR=------------------------------------------------------------------- x1000
Total live births in the same year
Post-neonatal Mortality Rate: It is defined as the ratio of post neonatal deaths (28 days to under
one year) in a given year to the total number of live births in the same year, usually expressed as a
rate per 1000.
No. of deaths of children between 28 days
and one year of age in a given year
PNMR = ------------------------------------------------------- X 1000
Total live births in the same year
Peri-natal Mortality Rate (PMR): It is defined as number of foetal deaths (28 weeks gestations &
more) + early neonatal deaths (Ist week) in one year per 1000 live births in the same year
Number of foetal deaths (28 weeks gestations & more)
+ Early neonatal deaths (Ist week) in one year
PMR=-------------------------------------------------------------------X 1000
Live births in the same year
Infant Mortality Rate (IMR): Defined as the ratio of infant deaths in a given year to the total
number of live birth in the same year, usually expressed as a rate per 1000 live births.
No. of deaths of children less than 1 year of age in a year
IMR=----------------------------------------------------------------------X 1000
No. of live births in the same year
Under 5 Mortality Rate (U5MR): It is defined as annual number of deaths of children under 5 years
of age expressed as a rate per 1000 live births.
No of deaths of children <5 years of age in a given Year
U5MR = ---------------------------------------------------------------X1000
No. of live births in the same year
Maternal Mortality Rate (MMR): Total No. of female deaths due to complications of pregnancy
per 1000 births (live + still) and abortions.
20
Number of deaths of the females due to complications of
pregnancy or within 42 days from puerperal causes in an
area during a given year x 1000
MMR = ---------------------------------------------------------------------Total No. of pregnancies terminated as birth (still or live)
+ abortions in the same area and year
Number of deaths of the females due to complications of
pregnancy or within 42 days from puerperal causes in an
area during a given year
Maternal=---------------------------------------------------------------x1000
Mortality Total No. of live births in the same area & year
Ratio
Exercise:
Consider following data for a village.
Total population -2500
Population of infants-70
And numbers of still births (10) + live (80) in one year.
Total births are 90
Infant deaths -10 (neonatal =2, post-neonatal=8)
Under five deaths-14
Maternal deaths -2
Total deaths in one year-25
Contd.
Exercise
Calculate the following rates /ratios based on the data given above and compare with national
data.
1. Still birth ratio
2. Still birth rate
3. Perinatal mortality
4. Neonatal mortality rate
5. Infant mortality rate
6. Under five mortality rate
7. Maternal mortality rate
8. Maternal mortality ratio
9. Crude death rate
10. Post neonatal mortality rate
21
Case Fatality Rate: Case fatality rate represents the killing power of a disease. It is simply the ratio
of deaths to cases. The time interval is not specified. Case fatality rate is typically used in acute
infectious diseases (e.g. food poisoning, cholera, and measles). Its usefulness for chronic diseases is
limited because the period from onset to death is long and variable. The case fatality rate for the
same disease may vary in different epidemics because of changes in the agent, host and
environmental factors. Case fatality is closely related to virulence.
Total No of deaths due to a particular disease
Case fatality rate=------------------------------------------------------ X 100
Total no of cases due to the same disease
Adjusted (Standardized) Rate: If we want to compare the death rate of two populations with
different age composition, the crude death rate is not the right yardstick. This is because rates are
only comparable if the populations upon which they are based are comparable. And it is
cumbersome to use a series of age specific death rates. The answer is “age adjustment” or “age
standardization”, which removes the confounding effect of different age structure and yields a
single standardized or adjusted rate, by which the mortality experience can be compared directly.
The adjustment can be made not only for age but also for sex, race, parity, etc.
VII MEASUREMENTS OF FERTILITY
i
Crude Birth Rate: Defined as the number of live births per 1000 estimated mid year population
in a given year.
No of live births during the year
Birth Rate = ---------------------------------------X 1000
Estimated mid year population
ii
Total Fertility Rate (TFR): It represents the average number of children a woman would have if
she were to pass through her reproductive years (15-45 years) bearing children at the same
rates as the woman now in each age group. It is computed by summing the age specific rates
for all ages. If 5 years age groups (intervals) are used, the sum of the rates is multiplied by 5.
This measure gives the approximate magnitude of completed family size. In India TFR in the
year 2003 is estimated to be 2.8, i.e., on an average one woman gives 2.8 live births during her
reproductive period.
Example: Computation of the specific fertility rate and total fertility rate from the data given
below:
Age group (Years)
No. of women
No. of live births
15-19
(A)
(B)
25000
800
22
20-24
20000
2400
25-29
19000
2000
30-34
16000
1500
35-39
14000
120
40-44
6000
10
Total
100000
6830
Computation of age specific fertility rate:
Step I:
C=B/AX1000
For age 15-19 years = 800/25000x1000=32.00
For age 20-24 years = 2400/20000x1000=120.00
For age 25-29 years = 2000/19000x1000=105.26
For age 30-34 years = 1500/16000x1000=93.75
For age 35-39 years = 120/14000x1000=8.57
For age 40-44 years = 10/6000x1000 = 1.67
Step II:
Total Births=CX5
Exact age (years)
SFRx5
Total
births
per
1000 females aged
15 to 44 by stated
ages
15-19
32x5=160
160
20-24
120x5=600
760
25-29
105.26x5=526.30
1286.30
30-34
93.75x5=468.75
1755.05
35-39
08.57x5=42.85
1797.90
40-44
01.67x5=8.35
1806.25
Total fertility rate (TFR) = sum of S.F.R./1000
23
= 1806.25/1000
= 1.8
iii
Net Reproduction Rate (NRR): NRR is defined as the number of daughters a new born girl will
bear during her life time assuming fixed age specific fertility and mortality rate. NRR is a
demographic indicator. NRR of 1 is equivalent to attaining approximately the 2-child norm. If
the NRR is less than 1 then the reproductive performance of the population is said to be below
replacement level.
The Demographers are of the view that the goal of NRR 1 can be achieved only if effective couple
protection rate is above 60%.
Example:
Age group
Female
Female
Specific
Survival rate S.F.R. x S
population
births
fertility rate (S)
per women
(S.F.R.)
15-19
1600000
19000
0.0119
0.921
0.0110
20-24
10,00000
70200
0.0702
0.901
0.0633
25-29
16,8500
90600
0.0538
0.885
0.0476
30-34
17,30000
62400
0.0361
0.862
0.0311
35-39
1,72000
32500
0.0188
0.850
0.0160
40-44
16,20000
11000
0.0068
0.832
0.0057
Total
0.1747
NRR=sum (S.F.R. x S) x 5
= 0.1747 x 5
= 0.8735
24
PRACTICE QUESTIONS
1. To evaluate the performance of a new diagnostic test, the developer checks it out on 100 known cases of
the disease for which the test was designed, and on 200 controls known to be free of the disease. Ninety of
the cases yield positive tests, as do 30 of the controls. Based on these data, the specificity and false positive
error rates of the test are, respectively,
a. 75% and 10%
b. 85% and 10%
c. 85% and 15%
d. 85% and 25%
e. 90% and 15%
Based on all the information currently available, you estimate that the patient in your office has a one in
four chance of having a serious disease. You order a diagnostic test with sensitivity of 95% and specificity of
90%.
2. The result comes back positive. Based on all the information now available, the chance your patient really
has the disease is closest to
a. 100%
b. 95%
c. 90%
d. 75%
e. 60%
f. roughly 30%
3. The result comes back negative. Based on all the information now available, the negative predictive value
is closest to
a. 1%
b. 2%
c. 5%
d. 10%
e. 15%
f. 25%
4. Test A has 70% sensitivity and 90% specificity. Test B has 90% sensitivity and 80% specificity. Assuming
that responses to Tests A and B are statistically independent, and assuming pre-test probability of disease of
50%, determine the sensitivity and specificity, as well as the positive and negative predictive values, of
a. using Test A and Test B in parallel.
b. using Test A and Test B in series, Test A first.
c. using Test A and Test B in series, Test B first.
25
5. A test with 99.9% sensitivity and 99% specificity is used to screen a population for a disease with 1%
prevalence. The proportion of test positives in the screen who actually have the disease will be roughly
a. 10%
b. 30%
c. 50%
d. 90%
e. 99%
f. 99.9%
6. The American Disease X Foundation reports that 6% of the population over 50 years of age has Disease X.
You inquire as to the source of their information, and they cite disease population screening data in the
literature which reports that 6% of that population was positive when screened. Referring to the literature,
you discover that the screening test used had sensitivity of 95% and specificity of 98%. What proportion of
the population over 50 years of age do you think really has the disease?
7. Three tests exist that might be used in screening a population for Disease D, which you believe is present
in about 1% of the population. Test A has sensitivity of 99% and specificity of 99.9%. Test B has sensitivity of
95% and specificity of 99%. Test C has sensitivity of 99.9% and specificity of 98%. Using the percentage of
test positives to estimate the population prevalence of the disease would most help you support the
corresponding institutional position, if you were
a. CEO of the American Disease D Foundation
b. Newt Gingrich
c. Director of the UI's Institute for Truth in Medicine
8. In an article in the Archives of Your Specialty, researchers report that screening Test T is enormously
effective, and should be used routinely. As evidence, they report that the five-year survival rate of patients
whose disease was discovered by screening with Test T is 90%, whereas the five-year survival rate of
patients whose disease was discovered by other means is only 60%. However, in an article that same month
in the Journal of the College of Your Specialty, another group of researchers report that screening with Test T
has no effect. As evidence, they report that a study which randomized subjects to a program of routine
screening with Test T or to no special screening regimen found an 80% five-year survival rate in both groups.
The issue seems even more confusing because this second group of investigators acknowledges that if their
data are reanalysed to compare the survival rate of subjects who actually followed the screening regimen to
those who did not, whatever group they were assigned to, the cohort of those who actually were screened
had five year survival of 85% whereas the cohort of those who were not had survival of only 75%. Despite
this, these investigators maintain the position that no effect of screening has been demonstrated. Write a
brief note for the General Practitioner's Quick Office Practice Digest, explaining why these various sets of
results might be expected to in the way they do and advising whether or not to screen with Test T.
26
9. An article in The New York Times last year, in connection with the prostate cancer treatment of Buffalo
Bills head football coach Marv Levy and Washington, D.C. mayor Marion Barry, pointed out that annual
prostate cancer diagnoses have almost doubled since 1990, and that most experts attribute this to increased
detection of existing cancer via the prostatic specific antigen (PSA) test. The Times article suggested that
early detection via the PSA test was leading to early and inevitably more successful treatment of prostate
cancer, with a cure rate in the 80-90% range for men with early diagnosis. The Times gave no specific data
pertaining to the beneficial effect of the increase in early diagnosis produced by use of the PSA.
Among the data that might be used to support claims that use of the PSA is improving the health outcomes
of prostate cancer victims are
a. the sensitivity and specificity of the PSA test;
b. the positive and negative predictive values of the PSA test in the specific population of interest;
c. the overall five-year post-dx survival rate (sometimes called the "cure rate" in cancer studies);
d. the difference in such rates between men diagnosed by PSA tests as compared to those diagnosed by
other means;
e. the difference in such rates between men who've previously had one or more PSA tests as compared to
those who've not, whatever the method of diagnosis;
f. the mean overall post-dx survival;
g. the difference in these means between men who've been diagnosed by PSA tests as compared to those
diagnosed by other methods;
h. the difference in these means between men who've previously had one or more PSA tests as compared to
those who've not;
i. the age-adjusted mortality rate for prostate cancer;
j. the difference in rates of diagnosis between men randomly assigned to receive periodic PSA screening and
men randomly assigned to periodic digital rectal examination;
k. the difference in five year post-dx survival rates between men randomly assigned to receive periodic PSA
screening and men randomly assigned to periodic digital rectal examination;
l. the difference in age-adjusted mortality rates for prostate cancer between men randomly assigned to
receive periodic PSA screening and men randomly assigned to periodic digital rectal examination.
With reference as appropriate to particular biases, explain why each of the above types of data does or does
not provide reliable information on the impact of PSA on the health of men with prostatic cancer.
10. Which of the following is not conducive to success of a medical screening program?
a. high incidence
b. long duration of in apparent disease
c. excellent therapeutic results at all stages
d. screening inexpensive
e. high specificity of the test
11.To avoid being misled by stage-migration bias in comparing outcomes over different periods of time
between which diagnostic acuity has changed, we should
a. compare stage-specific outcome measures
b. compare directly stage-adjusted outcome measures
c. evaluate outcomes in the later period using the SMR based on reference outcome rates from the earlier
27
period
d. compare outcome measures combining and unadjusted for disease stage
ANSWERS
1.c
2.d
3.f
4. a. Sensitivity = 1 - (1-.7)x(1-.9) = 97%; Specificity = .9x.8 = 72%;
For PV+, post-test odds = 1x(.97/.28) = 3.46,
PV+ = 3.46/4.46 = 1x(.97/.28) = 78%;
For PV-, post-test odds = 1x(.03/.72) = .042,
PV- = 1 - (.042/1.042) = 96%.
b. and c. Sensitivity = .7x.9 = 63%;
Specificity = 1 - (1-.9)x(1-.8) = 98%;
predictive values 97% and 73%, calculated as above.
5.c
6. 4.3%
7. a)c
b)a
c)a
8. In the first study there was lead time bias, length/time bias, and compliance bias. In the second study,
when they origionally did the randomized clinical trial those biases were gone due to randomization, but
when they (non-randomly) re-grouped within the randomized groups the biases came back. The screening
therefore does not seem to help.
9. l
10.c
11.d
Source:https://www.med.illinois.edu/m2/epidemiology/ReviewQuestions/SensitivitySpecificity_Q
uestions.htm
28
EXERCISE
After a New Years Day breakfast of the 22 members (of whom 12 are women) of the Town Council
at Restaurant X, a number of the attendees became ill with fever, nausea, vomiting, headaches,
abdominal cramps, and diarrhea. Some developed jaundice, and complained of dark colored urine.
After interviews with 15 council members, the following line listing was created.
Foods Eaten
ID
AGE
SEX
ILL
ILLNESS
ONSET
Eggs &
Bacon
Pan
Cakes
Coffee
Milk
Cup
Cakes
1
38
M
Y
1/23
N
N
N
Y
Y
2
35
M
Y
1/24
Y
Y
N
Y
?
4
35
F
Y
1/26
N
Y
Y
Y
Y
7
68
F
Y
2/2
Y
Y
Y
Y
N
8
58
M
Y
2/2
Y
Y
Y
N
Y
9
53
M
Y
2/4
N
Y
Y
N
Y
11
57
M
Y
2/6
N
Y
N
Y
Y
12
59
F
Y
2/7
N
Y
Y
N
Y
14
33
F
N
Y
Y
Y
Y
N
3
41
M
N
N
Y
N
N
N
5
43
F
N
Y
N
?
Y
Y
6
61
M
N
N
Y
Y
Y
?
10
38
F
N
N
Y
Y
Y
N
13
62
F
N
Y
Y
Y
N
?
15
29
M
N
?
Y
Y
Y
N
1. In making the decision of whether this is an epidemic/outbreak the key factor is
duration of time between exposure and illness
frequency of illness relative to the endemic level
number of people involved
severity of illness
whether the illness was infectious
2. The best estimate of the attack rate per hundred for women is
29
14 (3/22*100)
32 (7/22*100)
25 (3/12*100)
38 (3/8*100)
67 (8/12*100)
3. What is the most likely infected food?
eggs & bacon


pan cakes

coffee

milk

cup cakes
Two food items are often eaten together (for example, bread and butter) and one item is
contaminated with an agent that causes illness and the other is not.
4. After the determination of attack rates for individuals who consumed and did not consume
each item:
the contaminated item will show a high relative risk but the uncontaminated one will
not.
the uncontaminated item will show a high relative risk but the contaminated one will
not.
both items will show high relative risks.
neither item will show a high relative risk.
5. The uncontaminated item is called:
an effect modifier
a confounder
a causal factor
a negative correlate
Attack rates were determined for the following four groups of individuals:
Group A - consumed item 1 and item 2
30
Group B - consumed item 1 but not item 2
Group C - consumed item 2 but not item 1
Group D - consumed neither item 1 nor item 2
6. If item 2 is the contaminated item, attack rates will be highest in Groups:
A and B
B and C
C and D
A and D
A and C
7. The attack rate, as determined from a sudden outbreak of disease, is:
an incidence rate
a prevalence rate
an attributable risk
a relative risk
8. An age-adjusted mortality rate for a given population will be lower than the crude mortality
rate when that population has
a good health care system.
more efficient methods for handling death certificates.
more elderly people than the standard population.
less elderly people than the standard population.
9. The case fatality rate for a disease could be high for all of the following reasons except
no efficacious treatment for the disease has been discovered.
methods for preventing the disease have not been developed.
detection of the disease is difficult during the stage when it is treatable.
the disease moves rapidly to a highly lethal stage.
10. The cause-specific mortality rate for a disease will be high when
the prevalence rate and the case fatality rate are both high
the prevalence rate is high but the case fatality rate is low
the prevalence rate is low but the case fatality rate is high
31
the prevalence rate and the case fatality rate are both low
11. Public health initiatives are concerned with disease prevention and treatment.
A public health program which is effective in reducing the probability of acquiring a certain
disease for all members of the population should
decrease both the incidence rate and the prevalence rate of the disease.
decrease the incidence rate but increase the prevalence rate of the disease.
not change the incidence rate but decrease the prevalence rate of the disease.
not change the incidence rate but increase the prevalence rate of the disease.
not change either the incidence rate or the prevalence rate of the disease.
12. A public health program which effectively provides treatment that prolongs the lives of those
in the population with a certain disease should
decrease both the incidence rate and the prevalence rate of the disease.
decrease the incidence rate but increase the prevalence rate of the disease.
not change the incidence rate but decrease the prevalence rate of the disease.
not change the incidence rate but increase the prevalence rate of the disease.
not change either the incidence rate or the prevalence rate of the disease.
The incidence of a certain disease is 6 per 100,000 per year for factory workers exposed to lead
dust and 2 per 100,000 per year for similar workers not exposed to lead dust.
13. The relative risk of this disease for those with lead dust exposure is
0.33
2
3
4
6
14. According to the attributable risk, the number of cases of the disease which could be
prevented per year for every 100, 000 workers with lead dust exposure is
0.33
2
32
3
4
6
15. In the investigation of a sudden outbreak of food born disease, potential sources can be
identified by the discovery of items with:
high relative risks
high attributable risks
either of the above
neither of the above
EXERCISE 2
Elderly men with hip fractures were followed to determine the time needed after surgery for them
to recover their pre-fracture walking ability. The recovery times had a mode of 9 months, a median
of 11.5 months, and a mean of 15.2 months.
1. The frequency distribution of recovery times
had at least three peaks.
was symmetric about its mode.
could be well described by the normal curve.
was skewed.
2. The 25th percentile of the recovery time distribution was
9 months.
11.5 months.
less than 11.5 months.
more than 11.5 months.
3. The standard deviation for the recovery time was 8.3 months. The interval given by the mean
plus or minus two standard deviations cannot be used to establish normal limits for recovery
time because
the normal curve is not a good model for this distribution.
the standard deviation is too large.
33
the standard deviation is too small.
the standard error is needed instead of the standard deviation.
Sixty percent of patients with pulmonary dysfunction are smokers and 80% of individuals with
normal pulmonary function are non-smokers. The prevalence of pulmonary dysfunction in the
population is 30%.
4. What is the probability of pulmonary dysfunction for smokers?
0.12
0.32
0.56
0.60
0.80
5. What is the proportion of the total population who are non-smokers with pulmonary
disfunction?
0.12
0.32
0.56
0.60
0.80
6. What is the prevalence of smoking in the population?
0.12
0.32
0.56
0.60
0.80
The performance measures of a screening test can always be interpreted as probabilities.
7. The predictive value of a positive test is
34
the probability of testing positive given that the disease is present.
the probability of testing negative given that the disease is absent.
the probability of the disease being present given that the test is positive.
the probability of the disease being present given that the test is positive.
8. The sensitivity of the test is
the probability of testing positive given that the disease is present.
the probability of testing negative given that the disease is absent.
the probability of the disease being present given that the test is positive.
the probability of the disease being absent given that the test is negative.
9. The predictive value of a negative test is
the probability of testing positive given that the disease is present.
the probability of testing negative given that the disease is absent.
the probability of the disease being present given that the test is positive.
the probability of the disease being absent given that the test is negative.
10. The specificity of the test is
the probability of testing positive given that the disease is present.
the probability of testing negative given that the disease is absent.
the probability of the disease being present given that the test is positive.
the probability of the disease being absent given that the test is negative.
Four screening test are being considered for early detection of Disease X. The sensitivity and
specificity of each test is shown below:
Test
Blood Test
Sensitivity Specificity
80%
70%
Physical exam 60%
90%
Ultrasound
90%
60%
Urinalysis
70%
90%
11. Of these four tests, which will fail to detect the most cases of disease X in a screened
population?
35
Blood test
Physical exam
Ultrasound
Urinalysis
One thousand people (500 who have colon cancer and 500 who do not have colon cancer) receive
a fecal occult blood test (FOBT). The results are shown in the table below:
Test
Colon cancer No colon cancer
FOBT positive 300
100
FOBT negative 200
400
Total
500
500
12. Based on these data, we can conclude that the specificity of FOBT as a screening test for the
detection of colon cancer is closest to
20%
40%
60%
80%
The mean cholesterol level for a sample of cases of women with hypertension during pregnancy
was found to be 212 mg%. The lower 95% confidence limit on the population mean was
determined as 192 mg%.
13. The standard error was
5 mg%
10 mg%
15 mg%
20 mg%
14. The upper 95% confidence limit was
212 mg%
222 mg%
36
232 mg%
242 mg%
15. If the mean cholesterol for normotensive pregnant women was 200 mg%, it would be safe to
conclude that women with prenatal hypertension have cholesterol levels that are
lower than expected.
higher than expected.
exactly as expected.
perhaps higher or lower than expected.
Volunteers who smoked ten or more cigarettes per day were randomly assigned to use either a
nicotine or a placebo inhaler. The subjects were blind to the identity of their treatment. Of the 145
subjects assigned to the nicotine group, 22 eventually quit smoking. There were 7 who quit
smoking among the 141 subjects assigned to the placebo group.
16. The relative risk for quitting, associated with the use of the nicotine inhaler, is
0.32
3.06
3.42
30.6
34.2
17. Based on a test of the null hypothesis that the quit rates are identical in the two groups,
P<0.001, the best interpretation is that
the P-value shows that the difference in quit rates is not clinically significant
a statistically significant difference in quit rates was attained.
the difference in quit rates could easily be explained by chance alone.
less than one in a thousand trials of this kind will result in a difference as large as that
found.
18. In a subsequent trial, similar subjects were randomized to either a nicotine inhaler or a
nicotine patch. A quit rate of 18.1% was attained in the former group and one of 21.6% in the
latter, P>0.10. Therefore,
the P-value shows that the difference in quit rates is not clinically significant .
37
a statistically significant difference in quit rates was attained.
the difference in quit rates could easily be explained by chance alone.
more than one in a ten trials of this kind will result in a difference as large as that found.
The postnatal weight gain (Y) in pounds over a specified period of time was related to varied
amounts of a formula supplement (X), in unit doses, taken during the same period for a sample of
70 infants. The following results were obtained:
Regression equation: Y = 1.0 + 0.8 X
Correlation coefficient: r = .64, P<0.05
19. All of the following statements are reasonable conclusions except
Infants not taking the supplement are expected to gain one pound during the period.
The extra weight gain, attributed to the supplement, is not likely to be the result of
random variation in the data.
There is a strong correlation between weight gain and the amount of supplement taken.
An infant taking 0.5 units of the supplement during the time period is expected to gain
1.4 pounds.
An infant taking 0.25 units more of the supplement than another infant during the time
period is expected to gain 0.2 punds more
20. If the weight gain was expressed in grams rather than pounds,
the slope would increase and the correlation coefficient would remain the same.
the slope would decrease and the correlation coefficient would remain the same.
the slope would remain the same and the correlation coefficient would increase.
the slope would remain the same and the correlation coefficient would decrease.
the slope would remain the same and the correlation coefficient would remain the
same.
Plasma serum levels of betacarotene (Y) in mg/dl were related to body mass index (X1) and
cigarette smoking (X2) for a sample of 200 volunteers with a multiple regression equation. The
independent variable X2 took a value of 1 if the volunteer was a current smoker and 0 otherwise.
The following results were reported:
Regression equation: Y = 3.1 - 0.10 X1 - 1.0 X2
Coefficient of determination: R2 = .30
38
21. Tests of the null hypothesis of zero slope gave P-values less than .05 for both independent
variables. Thus a smoker with a body mass index of 20 as compared to a non-smoker with a
body mass index of 30 is expected to have a beta carotene level which is
2 mg/dl lower.
1 mg/dl lower.
the same.
1 mg/dl higher.
2 mg/dl higher.
22. In using the regression analysis given in the previous problem to estimate the effect of
cigarette smoking on levels of betacarotene (i.e. mean levels) we must assume
100% of the variance in betacarotene is accounted for by body mass index and smoking.
the effect of smoking is constant over all levels of body mass index.
all individuals in the population will have the same body mass index.
about half of the population will be current cigarette smokers.
all of the above.
23. The reduction in betacarotene attributed to smoking is likely to be the result of
a low coefficient of determination.
random variation in the data.
the fact that smokers tend to have high body mass.
the fact that smokers tend to have low body mass.
none of the above.
39
SECTION – B
SurveillanceMethods, use and example
40
SURVEILLANCE
Learning Objectives
At the end of the session, participants will be able to:




List the various VPDs and their standard case definitions.
Define surveillance and list its uses.
Explain the steps in conducting VPD surveillance and outbreak investigation
Surveillance of Vaccine Preventable Diseases
Each individual case of VPD needs to be recorded and reported upwards within a comprehensive
VPD surveillance system. The following section provides an overview of the components of VPD
surveillance.
Definition of Surveillance
Surveillance is data collection for action. It is defined as the ongoing and systematic collection,
analysis, interpretation, and dissemination of data about cases of a disease and factors influencing
disease behavior, which is used as a basis for planning, implementing and evaluating disease
prevention and control activities, including immunization.
Key elements of a Surveillance system





detection and notification of VPDs
investigation and confirmation (epidemiological, clinical, laboratory) of VPDs
collection, analysis and interpretation of data
feedback and dissemination of results
prevention and control responses
Uses of Surveillance
Disease surveillance enables the following:






Predicting or detecting disease outbreaks for containment (What disease is occurring)
Identifying high-risk populations (Who gets the disease)
Identifying areas requiring special attention and where system performance is poor (Where the
disease is occurring)
Determining the frequency of occurrence of a disease in the community and magnitude of the
problem (When the disease is occurring and how many get the disease)
Identifying underlying causes (or risk factors) of the disease (Why the disease is occurring)
Guiding response activities, including immunization (How the disease can be prevented, controlled
or eliminated).
Prerequisites for effective Surveillance
Standard case definitions (to ensure uniformity in reporting)
Recording and reporting system (to ensure regularity in reporting)
List of all the reporting units (to ensure completeness in reporting)
41
The quality of surveillance data depends upon correct diagnostic criteria, timeliness and
completeness of reports.
STEPS IN CONDUCTING SURVEILLANCE
The five steps in surveillance, carried out at various levels (sub-center upwards), include:
Step1: Collect data
Collect data on the cases and deaths due to all VPDs in your area. The three different data
collection methods are:
Passive/Routine Surveillance: Data is collected and reported monthly by all the reporting units
(from the SC upwards) in the UIP format. However, Weekly reporting is required for AFP
surveillance. Detailed information regarding individual cases is essential for diseases under
eradication or elimination such as poliomyelitis and Neonatal tetanus.
Reliable sources of data for routine surveillance include outpatient and inpatient registers, and
individual patient records, including:




Cases that have visited a government health facility for treatment
Cases seen by health workers during outreach immunization sessions
Cases treated at non-government health facilities e.g. private practitioners, NGO-run hospitals etc.
Cases that were reported by ASHA/AWW/community or the media and verified by the visit of a
health worker
Active Surveillance: implies the collection of data on specific VPDs, through the review of records
during regular visits to selected health facilities, reporting sites or the
community. This method is used


During outbreaks to determine the extent of the outbreak and keep mortality rates low by initiating
early treatment.
When a disease is targeted for eradication or elimination (e.g. polio eradication) every possible case
must be found and investigated.
Active Surveillance does not replace passive surveillance, but if conducted regularly and frequently
it has the following advantages over passive surveillance, as it:





helps to improve the timeliness and accuracy of case detection and notification
enables rapid case investigation, including collection of laboratory specimens
helps to link cases epidemiologically.
enables timely action to be taken in response to the detected case
identifies areas where passive surveillance needs to be strengthened.
Sentinel Surveillance: Data is collected through reports from selected 'sentinel' sites, to
understand the disease burden, monitor trends and detect outbreaks. This system is used when
high-quality data are needed about a particular disease that cannot be obtained through a passive
42
system e.g. in AFP surveillance. The sentinel site is usually a hospital, health center, laboratory,
rehabilitation center or other facility which attends to a relatively large number of cases of the
disease.
Reporting units for VPD Surveillance
A reporting unit is a health facility/individual in private or public sector, located in rural or urban
area. Designated health workers/paramedical staff and medical officer/practitioner working in
various health facilities collect information on VPDs in the specified formats and report these in a
timely manner to the next higher level.
Follow these rules when reporting the total number of cases and deaths seen during a reporting
period (month or week):




Zero reporting: Submit nil reports even if there are no VPD cases seen.
Avoid double counting: if a child makes two visits to the health center for the same disease episode
count it as one case only.
Count only those cases which have been diagnosed by the health personnel.
Count current cases only: Include only those cases that occurred within the time frame specified
for the VPD.
Report the occurrence of any unusual clustering of VPD cases or any death immediately by
telephone, fax, email, special messenger etc. This verbal report must be followed by a written
case based report.
Step 2: Compile data
In terms of passive surveillance, you need to know how many VPD cases are occurring and where
they are occurring. The essential data you should receive from each reporting unit in the UIP report
of all sub-centers/ PHCs is the number of cases and deaths of each of the targeted diseases
counted during the reporting period.
In terms of active surveillance, additional information should include the:



Vaccination status of each case;
Name, age and sex of each case;
Date and place of onset of symptoms
43
Compile the data to describe the VPDs in terms of time, place and person. This can be done by
tabulation or drawing of graphs, bar charts or maps. Table 10.1 describes the immunization status
of measles cases (among infants older than 9 months of age) regarding a Measles outbreak in five
SCs in a PHC.
Step 3: Analyze and interpret the data
Regularly review the data from routine reports and check if it crosses the threshold level.
Threshold levels are determined based on three criteria:
1. Pre-existing National/Internationally developed thresholds: e.g. a single case of measles in a
tribal area is considered an outbreak
2. Based on Historical Data: e.g. if data for a particular disease is available, then the monthly
mean should be calculated for the previous three years (excluding months in which there was
an outbreak).
3. Increasing trends of the disease over a short duration of time (e.g. in weeks). If the number
of cases is found to be much below the threshold, you could interpret it as no cause for worry.
Alternatively, you could check for under-reporting or review the threshold value.
If the cases are approaching the threshold level or have crossed it, then suspect an outbreak.
Analyze the reports for surveillance quality as follows:
1) Completeness of reporting
The number of reports received divided by the number of reports expected, expressed as a
percentage. If the completeness of reports was only 50%, then the disease incidence would be
under-reported by 50%.
44
2) Timeliness of reporting
The number of reports received on time divided by the number of reports expected expressed as a
percentage. The definition of 'on time' must be clear to reporting units.
3) Description by time, place and person (when, where and who gets the disease?)
When the disease is occurring?
Compare the number of cases and deaths with previous weeks/ months/ years to see if there are
any seasonal or cyclic trends. Table, bar or line diagrams are tools that enable analysis across time
(temporal). These tools will help you to understand any increase or decrease in the incidence of a
disease or the number of deaths for a particular reporting unit (as compared to other reporting
units). Figure 10.1 shows yearly trend of measles cases and deaths in a tabular and graphic form.
The above data could be interpreted in the following manner. The increasing number of cases from
1999 onwards indicates a potential outbreak, improved reporting or a change in the detection and
reporting protocols. The decreasing number of cases from 2002 onwards indicates improved
control measures, under-reporting due to incomplete reports or change in the detection and
reporting protocols. The plateau in the graph from 2006 onwards indicates either a stable situation
or under reporting because of incomplete reports.
Where the disease is occurring?
Diseases tend to cluster in a particular area. Clustering indicates that a large number of similar
cases have occurred in a limited geographical area or have occurred around the index case. This
provides an idea of the causative and predisposing factors that may have played a role in the
occurrence of the VPD. See Figure 10.2.
45
A Spot map is a tool that enables analysis across space (spatial). It shows the occurrence of the
cases, high-risk areas, areas of poor immunization coverage or areas with vacancies of HWs.
A Spot map helps to identify:



Pockets from where cases are consistently reported
Pockets from where cases are expected but not reported
Disease trends in comparison to similar maps for the previous corresponding period.
Who gets the disease?
VPDs also tend to occur more in specific ages and sexes. Tables, bars or pie charts are tools that
enable analysis across specific age and sex groups. A high proportion of un-immunized VPD cases
are a reflection of low immunization coverage in the community. You could also compare
incidence and case fatality rate between different reporting units and between public and private
sources.
See Figure 10.3.
46
Step 4: Take action
After analysis and interpretation of data, take action to correct any problems identified to prevent
avoidable morbidity and mortality. If you find that there are:



More cases than you expect: Conduct an outbreak investigation and response.
Cases occurring in vaccinated children: This could be due to over-reporting, vaccination given at the
wrong age; incorrect technique of administration or dosage and breaks in the cold chain. Possible
interventions to deal with these could be improved supervision, capacity building and strengthening
the cold chain.
Fewer cases than you expect: This could be due to under-reporting of cases or actual improvement
of services. If the latter is true, there is no need for action.
Step 5: Provide Feedback
Feedback to the reporting sites refers to:




Commenting on the completeness, timeliness and accuracy of the surveillance reports;
Informing about the effectiveness of the vaccination activities in meeting the objectives of disease
reduction;
Offering information to help them in solving problems;
Congratulating the good performers and encouraging them to do a better job.
Feedback is essential to keep the staff motivated to achieve high levels of immunization coverage
and to collect accurate and complete data on the occurrence of target diseases. It may be urgent
for an outbreak or individual cases or specific e.g. the laboratory results of each AFP case. Feedback
to the community helps increase community trust and involvement. It must be shared during
monthly meetings as well as during visits to the reporting units.
47
SECTION – C
OUTBREAK INVESTIGATION
48
OUTBREAK INVESTIGATION, RESPONSE AND CONTROL
An outbreak is defined as the occurrence of an illness in a community, clearly in excess of the
expected numbers. Usually an outbreak is limited to a small focal area. When an outbreak covers a
larger geographic area and has more than one focal point, it is termed as an epidemic.
Outbreaks are defined differently for different VPDs. For diphtheria, polio, neonatal tetanus or
JE, even a single case is an outbreak, whereas for measles and pertussis, a sudden increase in the
number of cases is an outbreak. Refer to GoI guidelines for surveillance and outbreak response
for AFP and Measles.
SOURCE: Field Guide: Measles Surveillance and Outbreak Investigation, New Delhi, Government of India,
2006, (http://www.npsuindia.org/download/Measles%20Guide.pdf)
Field Guide: Surveillance of Acute Flaccid Paralysis, New Delhi, Government of India, 2005,
(http://www.npspindia.org/download/Redbook.pdf)
Warning signs of an impending outbreak are:



ƒ Clustering of cases or deaths in time and/or space
ƒ Occurrence of two or more epidemiologically linked cases of meningitis or measles
ƒ Shifting in the age distribution of cases
Investigation of an outbreak helps to:




ƒ control and limit its spread to other areas
ƒ ascertain its etiology and understand why it occurred
ƒ identify high risk areas and groups
ƒ assess how prevention strategies can be strengthened to reduce or eliminate the risk of future
outbreaks
Steps in Outbreak investigation
Prompt and timely action during an outbreak is critical to minimizing the damage and maintaining
public trust in health and immunization services. The emphasis should be on saving lives. Without
awaiting confirmation of a suspected outbreak, provide immediate logistic support to the field
teams. Once the cause of outbreak is confirmed, does not waste laboratory support for diagnosing
every case since, standard case management for epidemiologically linked cases DOES NOT require
laboratory confirmation.
Actions BEFORE an outbreak:
Form an Epidemic Response Team (ERT) which may include representatives from:





ƒ Local health officials (DIO/ any district level epidemiologist/ district officer in charge of
surveillance and the concerned BMO)
ƒ Hospital Clinician/ Public Health Nurse
ƒ Laboratory representative
ƒ NGO representative/ Community leader
ƒ Others as appropriate
The team that has been formed at district level should hold a meeting as soon as a suspected
outbreak is identified. It should decide on the area to be surveyed, plan and guide the outbreak
49
investigation, monitor progress in data collection, compile and analyze data and write a final
report.
Actions DURING an outbreak
STEP 1: CONFIRM THE OUTBREAK
Confirmation of an outbreak is done through two related steps. Firstly, you have to visit the area
concerned and confirm the diagnosis of as many reported cases as possible. Next, you should
ascertain its geographical spread through a preliminary search.
Confirm the diagnosis by:
Clinical criteria: according to the standard case definition using information obtained by history and
examination
Epidemiological association: If an outbreak has been confirmed and similar cases in the same area
in the same period of time are reported by health workers, but not investigated individually, they
may be confirmed by epidemiologically linked association with confirmed cases.
Laboratory tests: For VPDs subject to eradication or elimination, collect laboratory specimens from
every suspect case (e.g. stool sample from each AFP case). For VPDs subject to control, collect
specimens from a sufficient number of cases (e.g. five blood samples in case of a measles outbreak)
to confirm the outbreak. However, no laboratory specimens are required for neonatal tetanus.
Ascertain the geographical extent of the outbreak to the surrounding villages/ blocks. The search
for additional cases must include visits to:
The health facilities: Talk to the doctors and nurses to see if they are seeing suspected cases of the
VPD. Visit hospital wards and outpatient departments and search all patient registers for cases
that fit the standard case definition.
The community: Visit the area from where cases have been seen in the health facilities. Talk to
volunteers and other influential persons in the community. If feasible, organize a rapid house-tohouse search of the affected area(s) tosearch for similar cases. Identify key informants in each
village / ward for prompt information about any cases.
STEP 2: CONDUCT HOUSE-TO-HOUSE SEARCHES TO FIND ADDITIONAL CASES AND PROVIDE CASE
MANAGEMENT
Train and assign health workers to conduct house-to-house searches to find the cases in the
designated area. The logic is to list all the cases of VPD that have occurred in the recent past.
Investigate cases using one disease-specific 'Standard Case Investigation Form' (CIF) for each case.
Record the full details, including identification data, address, vaccination status and the travel
history. (See Appendix 10.2)
Provide standard case management/treatment to the cases. Trace contacts to establish chains of
transmission for containment measures such as Outbreak Response Immunization (ORI) in
Measles, Polio, etc. If a new case or outbreak has been detected, search for additional cases of the
VPD. For example, for a suspect measles or diphtheria case, enquire whether there are any other
contacts (in the specific age group) in the household or neighborhood. Provide need-based
prophylaxis and/or immunization to the contacts (e.g. vitamin A for measles, vaccination for
diphtheria). Health workers should notify the cases with complications to the supervisor for further
referral.
50
During the course of investigation, it may be possible that some other areas (not included in initial
planning) may report fresh cases of the VPD. Arrange to undertake case searches in these new
areas as well.
TRACE ELEMENT: A contact is a person who has been in close association with a known or
suspected case of a communicable disease during the incubation period.
STEP 3: LINE LIST AND NOTIFY THE CASES
From the Case Investigation Forms, create a line list of all cases including the name, address, age,
sex and immunization status. Include laboratory results as soon as these become available. Record
these in the suggested line list as shown in Table 10.2.
Report the cases immediately to the ERT in both the CIF and the line list consolidating data
acquired from all the CIFs.
EXERCISE: Plan a visit to a community and the nearest health centre and see different form
available there. See the line listing register.
What is the difference between line listing and case finding? See the forms given in appendix
used in IDSP.
STEP 4: DESCRIBE THE OUTBREAK
Describe the outbreak in terms of time, place and person.
Time: What are the dates of onset of cases?
Plot these to prepare an Epidemic curve i.e. a graph showing cases by date of onset or by date of
report (See Figure 10.4). It helps to demonstrate where and how an outbreak began, how quickly
the disease is spreading, the stage of the outbreak (start, middle or ending phase), and whether
control efforts are having an impact.
51
Place: Where do cases reside?
Prepare a Spot map (See Figure 10.2) of the area showing the location of all confirmed cases. It
helps to identify areas with clusters of disease. Further investigation of these areas may reveal
weaknesses in the local immunization program.
Person: Who are affected?
The Graph or table of age distribution and immunization status of cases (See Figure 10.3) are
prepared from the line list of cases. This information helps to identify the most affected age-groups
and those cases which were not preventable (e.g. those developing measles before the scheduled
age of immunization).
STEP 5: ANALYZE THE DATA TO:




Confirm the outbreak:
 Is the number of cases reported greater than the number expected for this period? (e.g.
threshold)
 What proportion of cases fulfill the case definition?
Define the extent of the outbreak (time, place and person)
Measure the severity of the outbreak. What proportion of confirmed cases were
 hospitalized,
 suffered complications or
 died (Case Fatality Rate)
Measure the effectiveness of vaccination
 How many confirmed cases occurred in vaccinated individuals and in unvaccinated
individuals?
 How effective was the vaccine at preventing infection (Vaccine Efficacy)
52
Case-Fatality Rate (CFR) is based on the case investigations and the total number of confirmed cases. If
possible, estimate it by age-group.
CFR = No. of patients who died of a specific VPD/Total No. of cases of the same VPD X 100
Vaccine efficacy (VE) is the ability of the vaccine to prevent disease effectively and is affected by the age at
immunization, potency of the vaccine (quality of cold chain) and overall immunization coverage.
VE = (Attack Rate among unvaccinated (ARU) -Attack Rate among Vaccinated (ARV)
(Attack Rate among unvaccinated (ARU)
Attack Rate is an incidence rate (usually expressed as a percent), used only when the
population is exposed to a VPD for a limited period of time, such as during an outbreak. It is
calculated as follows:
AR= Number of new cases of a VPD during a specified time interval X 100
Total population at risk during the same interval
EXERCISE:
Plan a visit to the district health office and medical record section. Interview the DHO and MRD
in charge regarding the criteria of confirming the epidemic?
STEP 6: USE THE DATA FOR ACTION
Use data on the various components of the immunization system such as coverage, status of the
cold chain, training and availability of personnel to determine the causes of the outbreak. The
reasons why susceptible accumulate in a group could be the following.
Failure to give vaccine: A high proportion of unvaccinated among the cases in an outbreak would
suggest that failure to vaccinate children was a significant factor. Spot maps will help to locate
cases, high-risk areas and clusters of cases indicating a failure of the program to reach a specific
geographic area or population subgroup.
Vaccine failure: The vaccines currently in use are relatively safe and effective. However, these
vaccines are not 100% effective. For example, the efficacy of measles vaccine is estimated to be
approximately 85% when given at 9 months.
Cold chain failure: If the efficacy of the vaccine appears to have been low across all age groups,
especially during a specific period of time, review the cold chain to ensure that it has been
functioning correctly. Identify and rectify the factors contributing to a cold chain failure.
STEP 7: WRITE THE REPORT
After conducting the outbreak investigation, prepare a short comprehensive report with the
following sections:







ƒ Introduction and background information about the area affected (population structure, health
facilities, regularity of RI sessions, health seeking behavior)
ƒ Review of status of VPDs and routine immunization (coverage data)
ƒ Short review of the VPD outbreaks in the past
ƒ VPD reporting and surveillance system
ƒ Confirmation of outbreak by serology (lab reports)
ƒ Data collection methodology (sample size, number of investigating teams, approach etc.)
ƒ Data analysis
 ƒ Time, place and person analysis of cases (charts, graphs, spot maps etc.)
 ƒ Age distribution and vaccination status analysis
 ƒ Analysis of Case Fatality Rate
53




 ƒ Probable reasons of outbreak
ƒ Population at risk
ƒ Case management
ƒ Response to outbreak
ƒ Conclusions and recommendations
Send the outbreak investigation report to concerned district and state government officers (See
Appendix 10.3).
STEP 8: GIVE FEEDBACK
Provide feedback to all levels (Community/ SC/PHC/CHC/District) on the outcomes of the VPD
outbreak investigation, in order to ensure that all stakeholders are aware of the reasons for the
outbreak, the actions initiated and the plan to prevent future outbreaks.
STEP 9: INITIATE ACTION
In all VPD outbreaks, effective case management and follow-up of cases is a priority. Thereafter,
conduct activities for strengthening and raising awareness of routine immunization.
CASE: Follow-up should be according to specific guidelines e.g. re-visit AFP cases
after 60 days of Reporting
54
55
56
57
58
Suggestions for Classroom Use
At a minimum, before beginning a case study, students will need to know the basic scientific steps
for investigating an outbreak. We recommend that teachers prepare for presenting an exercise by
reading the case study section by section and attempting to answer the questions before reviewing
the answer key. Here are some classroom approaches that have worked well:
To Present a case study





Divide the class into small work groups of five to ten students. Ask each group to assign a facilitator, a
recorder, and a reporter.
Hand out Part I and call on individual students from the class at large to read the narrative and questions out
loud.
Then have students work in their small groups to answer the questions.
Finally, have the groups report their responses to the whole class.
Move through the remaining sections in the same fashion.
Note that to avoid giving away answers, you should give students the parts of a case study
sequentially, as indicated. The slides related to the case study could be shown during the work
session or used in a wrap-up session.
To Evaluate What Students Have Learned


Use traditional testing on specific knowledge points regarding epidemiology and outbreak investigation
Use the sample problems and the national event problems found in medical quizzes, international and
national day celebration of public health importance.
To enrich your class' study






Invite local experts to speak to the class. These could include a public health official from the local health
department, a physician specializing in infectious diseases, or an infection control nurse from a local hospital.
Introduce students to the NICD, CDC's weekly publication featuring breaking news in national and
international health.
Have students access the articles found in Careers in Epidemiology and read, report on, and discuss them.
Have students read The Hot Zone, The Cobra Event, or other health-related literature.
Show the movie Outbreak.
Have students research the pioneers of public health, such as John Snow, John Graunt, and William Farr.
59
ANNEXURE- 1
FORMAT FOR OUTBREAK INVESTIGATION REPORT
General Information
State:
_____________________________________________________
District: _____________________________________________________
Town/PHC:
_________________________________________________
Ward/Village:
_______________________________________________
Population:
_________________________________________________
Background Information
Person reporting the outbreak:
Date of report:
______________________________
____________________________________________
Date investigations started:
__________________________________
Person(s) investigating the outbreak:
______________________________
Details of Investigation
Describe how the cases were found may include: (a) house-to-house search in the affected area; (b) visiting block areas adjacent to the affected
households; (c) conducting record reviews of local hospitals; (d) requesting health workers to report similar cases in their areas, etc.):
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
______________________________________
Descriptive Epidemiology
11.
12.
13.
Cases by time, place and person (attach summary tables and relevant graphs and maps).
Age-specific attack rates and mortality rates
High-risk age-groups and geographical areas.
Description of Control Measures taken
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
______________________________
Description of Measures for Follow-up Visits:
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
______________________________
Brief Description of Problems encountered
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
______________________________
Factors which, in your opinion, contributed to the outbreak
EXERCISE
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
Meerut district was reported to be affected by an “outbreak” of acute gastroenteritis (GE) in July______________________________
August,
2000. About
Conclusions
and Recommendations
2270 cases and 413 deaths occurred during this period. Most of the cases
had
only
diarrhoea
and
vomiting.
_____________________________________________________________________________________________________________________________
_____________________________________________________________________________________________________________________________
Q.NO.1. How will you decide whether or not the district was in the grip of an outbreak?
____________________________
Date
Note:
Designation)
(Table-1 Describes the reported data on GE from(Name
the and
Meerut
district during 1997-2000)
This report should be submitted by the investigating officer (State/District/PHC Nodal Officer) to the next higher authority within a
Tables and Graphs should be included wherever appropriate.
week
Table
1 of completion of investigation.
60
Cases and Deaths due to GE in district Meerut 1997-2000
Year
No. of cases
No. of deaths
1997
981
225
1998
375
112
1999
1387
173
2000
2380
426
Q.No.1.
Now, will you consider it an outbreak of GE? If yes why? If not, why?
________________________________________________________
________________________________________________________
* Analysis of the age distribution of 308 deaths revealed that about 9% of deaths occurred in
children below five years of age and about 62% of deaths occurred in adults above 20 years of age.
Q.No.2.
Does it help you in suspecting cholera as the cause of this outbreak?
________________________________________________________
________________________________________________________
Q.No.3.
What was the most disturbing features in this outbreak? Was it preventable?
* Rectal swabs from 59 cases were examined in the laboratories of NICD, Delhi. 15 Samples were
positive for V.cholerae O1 biotype E1 Tor. The isolates were sensitive to tetracycline, nalidixic acid,
ampicillin and chloramphenicol, but resistant to furazolidone and streptomycin. The other samples
were found negative for any enteropathogens.
Q.No.4.
pathogens?
What are the possible reasons for 44 of 59 samples being found negative for entero-
________________________________________________________
________________________________________________________
Q.No.5.
Assume yourself as the team leader for the investigation of this outbreak. (i) How
will you plan the investigations? (ii) How will you control the outbreak?
61
________________________________________________________
________________________________________________________
62
Student Exercises- Outbreak Investigation
Exercise 1
During the previous year, nine residents of a community died from the same type of cancer. List
some reasons that might justify an investigation.
Exercise 2
During August, a county health department received reports of 12 new cases of tuberculosis and 12
new cases of aseptic meningitis. Tuberculosis does not have a striking seasonal distribution;
however, aseptic meningitis, which is caused primarily by a viral infection, is highly seasonal, and
peaks from August–October. What additional information is needed to determine whether either
of these groups of cases is an outbreak?
Exercise 3
Review the six case report forms in the Appendix and create a line listing based on the information.
Case Report Forms
State Disease Report Form
State Disease Report Form
Name
McDowell, D.
Age
33
Phone
555-3707
Address
2020 Alabama
Sex
M
Race
W
City, State
Columbia
County
Columbia
Disease
Trichinosis
Hospital
Alerted?
Yes
Hospital Name
Columbia General
63
Date of Onset
7/27
Lab
Confirmation
Muscle
Biopsy
Admission Date
7/27
Discharge
Date
Lab Test Results
Eosinophilia = 2500
Comments (Clinical
description,
immunization theory,
etc.)
Possible
Exposure
ClevelandMcKay
Wedding
Physician Reporting
Dr. Baker
Phone
555-1900
Date of
Report
8/17
Name
Gordon, Jack
Age
26
Phone
555-1213
Address
110 Clifton St.
Sex
M
Race
W
State Disease Report Form
City, State
Columbia
County
Columbia
Date of Onset
8/14
Lab
Confirmation
Not Done
Admission Date
Discharge
Date
Lab Test Results
Eosinophilia = 37%
Comments (Clinical
description,
immunization theory,
etc.)
Possible
Exposure
ClevelandMcKay
Wedding
Physician Reporting
Dr. Gibbs
Phone
555-3841
Date of
Report
8/14
Disease
Probable Trichinosis
Hospital
Alerted?
No
Hospital Name
State Disease Report Form
64
Name
Thomas, Nancy
Age
27
Phone
555-3761
Address
2020 Alabama
Sex
F
Race
W
City, State
Columbia
County
Columbia
Disease
Trichinosis
Date of Onset
8/4
Lab
Confirmation
Not Done
Hospital
Alerted? Hospital Name
No
Admission Date
Discharge
Date
Lab Test Results
Eosinophilia = 18%
Comments (Clinical
description,
immunization
theory, etc.)
Possible
Exposure
ClevelandMcKay
Wedding
Physician Reporting
Dr. Stanley
Phone
555-0400
Date of
Report
8/14
State Disease Report Form
Name
Dickens, R.
Age
43
Phone
555-2662
Address
34 Whinfred Ave.
Sex
M
Race
W
City, State
Seattle, WA
County
King
Disease
Trichinosis
Date of Onset
7/25
65
Lab
Confirmation
Serologic
Hospital
Alerted?
No
Admission Date
Discharge
Date
Lab Test Results
Eosinophilia = 4100
Comments (Clinical
description,
immunization theory,
etc.)
Possible
Exposure
ClevelandMcKay
Wedding
Physician Reporting
Dr. Webster
Phone
555-0511
Date of
Report
8/15
Name
McKay, Alice
Age
54
Phone
555-6256
Address
406 Tugalo Ln.
Sex
F
Race
W
Hospital Name
State Disease Report Form
City, State
Brighton
County
Clayton
Date of Onset
8/14
Lab
Confirmation
Not Done
Admission Date
8/14
Discharge
Date
Lab Test Results
Eosinophilia = 3600
Comments (Clinical
description,
immunization theory,
etc.)
Possible
Exposure
ClevelandMcKay
Wedding
Physician Reporting
Dr. Mason
Phone
555-3291
Date of
Report
8/15
Disease
R/O Trichinosis
Hospital
Alerted?
Yes
Hospital Name
Columbia General
66
Exercise 4
You are called to help investigate a cluster of 17 men who developed leukemia in a community.
Some of them worked as electrical repair men, and others were ham radio operators. Which study
design would you choose to investigate a possible association between exposure to
electromagnetic fields and leukemia?
Exercise 5
The manager of a grocery store has reported a rash illness among the store’s workers. What type of
study would you use to determine the source of the outbreak? Why? What is the appropriate
measure of association? After reviewing the table in the Appendix showing the data on exposure to
celery for these workers, calculate the measure of association and interpret your results.
Rash
Exposed to Celery?
No
Total
Rash
Yes
25
31
56
No
5
65
70
Total
30
96
126
Hints for question no 1


One reason to investigate is simply to determine how many cases you would expect in the
community. In a large community, for instance, nine cases of a common cancer (e.g., lung,
breast, or colon cancer) would not be unusual. In a very small community, nine cases of
even a common cancer may seem unusual. If the particular cancer is rare, then nine cases
even in a large community may be unusual.
If the number of cases turns out to be high for that community, we might pursue the
investigation further. Our motive might be research—perhaps we will identify a new risk
factor (workers exposed to a particular chemical) or predisposition (people with a particular
genetic marker) for the cancer. Control and prevention may also be a justification. If we find
a risk factor, control and prevention measures could be developed. Alternatively, if the
cancer is generally treatable when found early and a screening test is available, then we
might try to determine not why these people developed the disease, but why they died
from it. For instance, if the problem were cancer of the cervix, detectable by Pap smear and
generally treatable if caught early, we might find (1) problems with access to health care, or
(2) physicians not following the recommendations to screen women at the appropriate
intervals, or (3) laboratory error in reading or reporting the test results. We could then
develop measures to correct the problems we found (public screening clinics, education of
physicians, or laboratory quality assurance).
67

If new staff needs to gain experience on a cluster investigation, training may be a reason to
investigate. If there is public concern, it may generate political pressure. Perhaps one of the
people affected is a member of the mayor's family. A health department must respond to
such concerns, but does not usually need to conduct a full-blown investigation. Finally, legal
concerns may prompt an investigation, especially if a particular site in the community is
implicated.
Hints for exercise 2
You need to know how many cases of each of these diseases usually occurs in this county during
August. Because tuberculosis is not seasonal, the number of cases could be compared with (a) the
numbers reported during the preceding several months and (b) the numbers reported during
August of the preceding few years. However, since aseptic meningitis is seasonal and peaks from
August–October, the number of cases during August is expected to be higher than the number
reported during the preceding several months, so you would need to compare with the numbers
reported during August of the preceding few years.
Hints for Exercise 3
The choice of information to include in a line listing is somewhat arbitrary. The following categories
are often included:
Identifying information


Identification number or case number, usually in the left-most column
Names or initials as a cross-check
Clinical information





Physician diagnosis
Was diagnosis confirmed? If so, how?
Symptoms
Laboratory results
Was the patient hospitalized? Did the patient die?
Descriptive epidemiology—time


Date of onset
Time of onset
Descriptive epidemiology—person



Age
Sex
Occupation, if relevant, or other seemingly relevant characteristics
68
Descriptive epidemiology—place


Street, city, or county
Worksite, school, day care center, etc., if relevant
Risk factors and possible causes

Specific to disease and outbreak setting
Here is one way that a line listing might be drawn up from the six case report forms on the
Cleveland-McKay wedding outbreak:
ID
Initials
#
Date of
Onset
Diagnosis
How
Confirmed
Age Sex
County
Physician
ClevelandMcKay
Wedding
1
KR
7/23
probable
trichinosis
Not done
29
M Columbia Goodman
Yes
2
DM
7/27
trichinosis
Biopsy
33
M Columbia
Baker
Yes
3
JG
8/14
probable
trichinosis
Not done
26
M Columbia
Gibbs
Yes
4
RD
7/25
trichinosis
Serologia
45
M
King
Webster
Yes
5
NT
8/4
trichinosis
Not done
27
F
Columbia
Stanley
Yes
6
AM
8/11
R/O trichinosis
Pending
54
F
Clayton
Mason
Yes
Hints for Exercise 4
Because the total population at risk is not well defined, you would use a case-control study. You
would begin by enrolling the 17 people already identified with leukemia as the case group. You
would also need to determine what group might serve as an appropriate comparison, or control,
group. Neighbors might be used for the control group, for example. In your case-control study, you
would determine whether each case-patient and each control had been exposed to
electromagnetic fields (however you defined that exposure). Finally, you would compare the
exposures of case-patients and controls.
Hints for Exercise 5
You would use a cohort study because the outbreak is small and confined. The appropriate
measure of association for a cohort study is relative risk, which is calculated in this case as the
attack rate for workers exposed to celery divided by the attack rate for those who were not
exposed.
The attack rate for exposed workers is 25 / 56, or 44.6%. The attack rate for workers who were not
exposed is 5 / 70, or 7.1%. Thus, the relative risk for exposure to celery is 44.6 / 7.1, or 6.3. This
means that workers who were exposed to celery were 6.3 times more likely to develop the rash
69
illness than those who were not exposed, and it is therefore likely that celery was the source of the
outbreak. However, before you could draw this conclusion, you would need to compare the
relative risk for celery with that for other vegetables and fruits to see if the implication is stronger
for any of them.
Then, to test the likelihood of your findings, you would need to calculate a test of statistical
significance such as chi-square for the item with the highest relative risk and look up the
corresponding p-value in a table of p-values. If the p-value was below .05, your findings would be
considered statistically significant.
Source:
1. cdc.gov. Excite, learning epidemiology
2. Immunization guide for immunization for medical officer
70
SECTION – D
Exercises on Research Methods
[for Promotion of Lung Health]
71
Practical exercise
Cause or association?
Scenario
A descriptive study in a large population of teenagers and young adults (n=25 000) has shown a statistically significant
association between the use of a new bronchodilator drug and the risk of dying from asthma. On the basis of this
finding there is a public outcry demanding the withdrawal of the drug from the market.
Would you regard this as justified?
If no, what explanation would you give?
If yes, on what grounds?
What further information would you need in order to evaluate whether or not this new drug causes fatal
asthma?
72
Practical exercise
Choosing Research Questions for Protocol Development
An essential aspect of the learning experience in this course is for small groups to work together throughout the week
on the development of a written research protocol. Based on past experience, the identification and precise
formulation of the study questions to be addressed by the protocol groups is the first major potential stumbling block
in the course. The following exercise may be helpful to assist course instructors and participants in coming to decisions
about study questions in a timely fashion, so that sufficient time is left for groups to work on the details of the
protocols.
The exercise can be done individually, or as a group ‘brainstorming’ session. The first step is best completed on the
first day of the course, and steps 2 and 3 on the second day (after the participants have had a chance to discuss topics
informally among themselves and with faculty).
1. Choosing the general domains or topic areas for focus
Relevance to health in the community:
Among conditions affecting lung health, the most frequent serious conditions in your region are (list them, be specific):
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
What criteria did you use to select these conditions?
Is the list the same for other countries (or regions)?
Interests and experience of the research team; Relevance to the political and social imperatives
Are there specific research questions or topics of particular interest to you or your colleagues, or that you know are of
particular interest to managers of health services or health spending in your region (list them):
73
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
2. Narrowing the focus
Combining aspects from the two lists above, list (? in order of priority), several topics or research questions for protocol
development.
Questions for the group to consider: What criteria will you use to decide what topics remain on the list? to decide the
order of priority? (interest of participants - ? by vote, consensus; fundability; seriousness of the disease; frequency of
the disease; prior experience of participants)
In previous courses, participants have found it useful to select 4 to 6 general topic areas that address different diseases
(or health-related states), or that reflect differing types of study populations (eg. clinical topics, health service delivery
issues, community or workplace studies, evaluation of treatments).
1.
2.
3.
4.
5.
6.
74
3.
From general ‘topics’ to study questions and specific objectives
At some point in the study question development process, participants in previous courses have found it useful to fill in
templates similar to the ones below for the study topics / questions identified (either after the initial brainstorming – to
help narrow the focus, or after 4-6 topics have been chosen).
Studies of disease in populations (natural history, determinants, etc)
Disease or
health-related
state
Target
population
Determinant(s)
of interest
Feasible?
Significance?
Intervention
possible?
Most likely
study design
Epidemiologic studies of clinical procedures, treatments, interventions, diagnostic tests
Procedure,
intervention,
etc
Patient group
Outcome to be
assessed?
Feasible?
Significance?
75
Implementation
likely?
Experimental
design
possible?
Practical exercise
Study Design
The following are a group of selected abstracts of scientific articles on lung health published in recent years (slightly
edited for purposes of this exercise). Each abstract describes a scientific study of an epidemiological nature, giving
setting, objectives, design, results and conclusions.
Read each abstract and then define what type of study design is described in the abstract, using the enclosed standard
form and taking into account the elements described in the preceding section.
In assessing the study design, first ask the question:
Was only one group (either a group of patients, or a group with a common experience/exposure) studied?
If the answer is no, ask:
Did the investigator choose which group an individual would be in or assign interventions to groups?
If the answer is no, ask:
When selecting the groups to be studied, did the investigator begin by selecting groups defined by the presence
or absence of disease, or did the investigator select according to the presence or absence of a common factor
or exposure?
If the answer is no, ask:
Was the presence of disease and of the factor or exposure thought to be associated with the disease measured
at the same point in time?
The answers to these questions should allow you to correctly determine which type of study design the investigators
have selected.
ABSTRACTS:
Study 1 - Short course chemotherapy for tuberculoma of the brain
Setting: Tuberculosis Research Centre, Madras, India
Objective: The efficacy of a short-course regimen in the treatment of brain tuberculoma and computerized tomography
scan appearance before, during and after antituberculosis treatment was studied.
Design: Patients aged over 5 years with tuberculoma of the brain diagnosed by CT scan were randomly allocated to one
of the following 2 regimens:
Regimen 1: rifampicin, isoniazid and pyrazinamide daily for an initial 3 months followed by rifampicin and isoniazid
twice-weekly for 6 months;
Regimen 2: rifampicin, isoniazid and pyrazinamide thrice-weekly for an initial 3 months followed by rifampicin and
isoniazid twice-weekly for 6 months.
The patients were followed intensively for 2 years from the start of treatment
Results: Of the 108 patients analysed (regimen 1: 56, regimen 2: 52), at the end of treatment clinical status was normal
in 91% in regimen 1 and 88% in regimen 2. Of the 91 patients with scan assessments, CT scan lesions disappeared at 24
months in 77% of 47 patients in regimen 1 and 80% of 44 in regimen 2, and in both groups 88% of the patients were
clinically normal. None had relapses requiring treatment.
Conclusions: Short-course regimens of 9 months’ duration are effective in the treatment of tuberculoma of the brain;
clinical recovery was faster than scan clearance.
76
Study 2 - Cigarette smoking as a risk factor for tuberculosis
Setting: The association between smoking and pulmonary tuberculosis has not often been studied.
Objective: To assess the influence of cigarette smoking on the development of active pulmonary tuberculosis in young
people who were close contacts of new cases of smear-positive pulmonary tuberculosis.
Design: A comparison of 46 patients with active pulmonary tuberculosis and 46 patients with positive tuberculin tests
but no active tuberculosis. Smoking habits were investigated using a questionnaire. Analysis was performed and odds
ratios adjusted for age, gender, and socio-economic status.
Results: Statistically significant differences were found in active smokers (OR 3.7, 95%CI 1.5 to 9.2). There was a doseresponse relationship between the number of cigarettes smoked daily and the risk of active pulmonary tuberculosis.
Conclusions: The data studies show that cigarette smoking is a risk factor for pulmonary tuberculosis in young people.
Tuber Lung Dis 1996;77:112-116
Study 3 - Impact on adherence of change from injectable to oral regimen
Setting: Out-patient tuberculosis clinics in Dar es Salaam, Tanzania
Objective: To measure the impact on patient adherence to directly observed ambulatory tuberculosis treatment of
substituting an all-oral regimen for one containing streptomycin.
Methods: The attendance of patients during the intensive phase of treatment was measured daily at two outpatient
clinics. During the observation period, treatment was changed from one containing stretptomycin to an all-oral
regimen and attendance proportions were compared when patients always, sometimes or never received streptomycin
during their treatment.
Results: No significant difference was observed in attendance between periods when patients received streptomycin
and when they were given an all-oral regimen.
Conclusions: Patient adherence to a completely oral regimen was indistinguishable from that when streptomycin was
used. Clear advantages in reduced cost, time and danger of nosocomial HIV infection are obvious with the all-oral
regimen.
Tuber Lung Dis 1995;76:286-289
Study 4- Resistance to antituberculosis drugs in Cameroon
Setting: Tuberculosis centre in Hopital Jamot, Yaounde, the sole referral facility for tuberculosis treatment
Objectives: To identify strains of M tuberculosis responsible for pulmonary tuberculosis and to determine the
prevalence of initial resistance to the main drugs used for treatment and to compare this prevalence between those
HIV positive and HIV negative
Design: 576 consecutive, previously untreated, adult patients with smear positive pulmonary tuberculosis, admitted
between July 1994 and December 1995 were studied. Standard species identification was carried out. Sputum was
cultured on Lowenstein-Jensen and Coletsos media. Susceptibility of isolates to major drugs was tested using the
indirect proportion method. HIV testing was performed with 2 ELISAs and confirmed with Western Blot.
Results: M. tuberculosis was isolated in 516 (90%) of the cases. Of the 516 cases, 92 (18%) were HIV positive. Of the 516
strains isolated, 164 (32%) were resistant to at least one drug. Resistance was noted as follows: 25% to one drug, 5.8%
to 2 drugs, and 1% to three or more. Initial resistance was most frequent to Streptomycin (20.5%), followed by
isoniazid (12.4%), rifampicin (0.8%) and ethambutol (0.4%). No significant difference was observed between HIVpositive and HIV-negative patients.
Conclusion: Initial drug resistance to M tuberculosis is relatively high in Yaounde.
Int J Tuberc Lung Dis 1997;1:110-114
77
Study 5 - Yield of acid-fast smears in laboratories in Tanzania
Setting: Routine laboratories in Tanzania performing sputum smears for acid-fast bacilli
Objectives: To determine the yield of smear examination under routine conditions in a low income country where
tuberculosis is common.
Design: Analysis of routine records in 34 rural smear laboratories using a common, standardized recording system,
identified 61,580 tuberculosis suspects with 141, 371 sputum smear examinations. Incremental yield of subsequent
sputum smears was determined based on the results obtained in those reported.
Results: The average proportion of cases found among suspects was 19% (range 14-24%). The incremental yield of
subsequent sputum smear examinations was estimated to be 83%, 12% and 4% on the three smears examined.
Conclusions: The incremental yield of a third examination, after two have been examined is relatively low. The
proportion of suspects found to be positive was higher than previously noted.
Trans Roy Soc Trop Med Hygiene 1996;90:258-261
Study 6 - Efficacy of BCG in Malawi
Setting: A district in Northern Malawi where BCG was introduced in 1974 using the Glaxo, freeze-dried vaccine
Objectives: To determine the protective efficacy of this vaccine against tuberculosis and leprosy
Design: The presence of a BCG scar was prospectively determined in 83,455 individuals residing in the district and
followed from 1979 to 1989 to determine whether they developed tuberculosis or leprosy.
Results: 414 new cases of leprosy and 180 new cases of tuberculosis were identified. Protection against leprosy was
estimated at 50% or greater in those with BCG scars, whereas no statistically significant protection could be
demonstrated against tuberculosis.
Conclusions: BCG affords better protection against leprosy than against tuberculosis
Lancet 1992;339:636-639
78
Evaluation of Study Designs
Study 1
Study 2
Is this study design experimental?
Is it a cross sectional study?
Is this a prospective cohort study?
Is this a retrospective cohort study?
Is this a case-control study?
Explain why you selected this study design:
Study 1
Study 2
Study 3
Study 4
Study 5
Study 6
79
Study 3
Study 4
Study 5
Study 6
Practical exercise
Case-control and Cohort Studies
A causal relationship between cigarette smoking and lung cancer was first suspected by clinicians in the 1920s on the
basis of clinical observations. To test this apparent association Richard Doll and Austin Bradford Hill carried out two
major studies. . The first was a case-control study, begun in 1947, in which the smoking habits of lung cancer patients
were compared with the smoking habits of other patients. The second was a cohort study, begun in 1951, which
related causes of death among doctors to their previously recorded smoking habits.
Part I: Case-control study
Data were obtained from patients in hospitals in and near London, over a 4-year period. Initially, 20 hospitals, and later
more, were asked to notify the investigators of all patients admitted with a diagnosis of lung cancer. These patients and
controls selected from in-patients with other disorders (primarily non-malignant) in the same hospitals at the same
time were then interviewed about their smoking habits.
A total of 1,465 cases of lung cancer, all under age 75, were included in the study. These patients were culled from a
larger number of which about 15% were not interviewed because of death, discharge, severity of illness, or inability to
speak English.
Diagnoses of lung cancer in nearly all cases were based on biopsy, autopsy, sputum cytology wih or without
bronchoscopic or radiographic evidence.
Interviews were conducted by four full-time social workers. Each worker, after interviewing a patient with lung cancer,
interviewed a control patient of the same gender and the same 5-year age group. Table 1 compares cases and controls
in terms of age and gender.
Table 1. Age and gender of cases and controls
Age group
25-34
35-44
45-54
55-65
65-84
Total
Cases
Men
17
116
493
545
186
1,357
Controls
Men
17
116
493
545
186
1,357
Women
3
15
38
34
18
108
Women
3
15
38
34
18
108
Table 2. Number and per cent of male cases and controls by amount smoked
Number of daily
cigarettes
Cases
Number
0
1-4
5-14
15-24
25-49
50+
Total
All smokers
Controls
%
Number
%
7
49
516
445
299
41
0,5
3,6
38,0
32,8
22,0
3,0
61
91
615
408
162
20
4,5
6,7
45,3
30,1
11,9
1,5
1,357
1,350
99,9
99,4
1,357
1,296
100,0
95,5
80
The study showed a clear association between smoking and lung cancer(Table 2), but differences between case and
control patients, particularly in terms of questionnaire response, might make the association spurious. Did lung cancer
patients, knowing they had lung cancer, tend to exaggerate their smoking habits? Did controls, knowing smoking is
‘bad for you’ tend to under-report their smoking? Did interviewers, through prior knowledge of the hypothesis tend to
exaggerate the smoking habits of lung cancer patients and minimize the smoking of controls? Possible answers to these
questions came from patients initially interviewed as presumed lung cancer cases but later found not to have the
disease. Table 3 compares the smoking habits of men aged 45-74 in this and other diagnostic groups.
Table 3. Percentage distribution of daily smoking habits for selected disease groups (standardized to age distribution
of population of England and Wales)
Disease group
Incorrectly presumed to have
cancer
Confirmed lung cancer
Other lung diseases
Other cancers
Other diseases
Average daily number of cigarettes
0
1-4
5-14
15-24
25+
5,3
0,3
1,9
4,6
5,6
9,9
4,6
9,9
9,4
9,0
35,5
35,9
38,3
47,2
44,8
37,8
35,0
38,7
26,0
26,9
Number of patients
11,4
24,3
11,2
12,8
13,7
202
1,224
301
473
875
Questions re Case-control Study
1.
How representative of all persons with lung cancer are cases admitted to hospital likely to be?
2.
How representative of all persons without lung cancer are other patients in hospital likely to be?
3.
What biases may have been introduced by failure to interview 15% of the cases?
4.
Why did the investigators require that control patients be of the same gender and age group as case patients?
5.
What do the data of table 2 suggest about the relationship between cigarette smoking and lung cancer?
6.
Compute the odds ratio for lung cancer occurring in all smokers compared with non-smokers. What does this
represent? What does it suggest with regard to the etiological role of cigarette smoking in lung cancer?
7.
If the ‘control’ patients were asthma patients, would this change your opinion about the etiological role of
cigarette smoking in lung cancer based on the results of this study?
8.
What does table 3 tell us? Why was age standardization of the data required?
Part II. Cohort study
In 1951, a prospective cohort study was undertaken to quantify the relation between smoking and lung cancer. The
study population comprised all physicians listed in the Medical Register and resident in England and Wales in October
1951. Information about present and past smoking habits was obtained by questionnaire. Deaths from lung cancer
were identified from death certificates and other mortality data recorded during ensuing years.
In October 1951 questionnaires were mailed to 59,600 physicians, seeking self-classification under any of 3 smoking
groups: [1] current smokers, [2] ex-smokers and [3] non-smokers. Smokers and ex-smokers were asked the amount
they smoked, their method of smoking, the age they started to smoke, and, if they had stopped smoking, how long it
81
had been since they last smoked. Usable responses to the questionnaires were received from 34,445 (85%) of the male
physicians.
The occurrence of lung cancer in physicians who responded to the questionnaire was documented over the next 10
years (November 1951 to October 1961) from death certificates filed with the Registrar General and from lists of
physician deaths provided by the British Medical Association. All certificates indicating that the deceased was a
physician were abstracted. For each lung cancer case, medical records were obtained to confirm the diagnosis. The
same clinical and pathologic criteria were used as in the earlier case-control study. Of 4,597 deaths in the cohort over
the 10 year period, 216 were reported to have had lung cancer, a diagnosis that could be documented in 4, leaving a
net total of 212 cases of lung cancer.
Table 4 shows lung cancer deaths by age and amount smoked. Rates are both age-specific and age standardized (ëall
agesí category) and are expressed as deaths per 1,000 person-years at risk.
Table 4. Age-specific lung cancer death rates per 1 000 person-years at risk, by age group and amount smoked
Age group
35-44
45-54
55-64
65-74
75+
Total all ages
(Standardized)
0
Number
1
0
0
0
2
3
Rate
0,05
1,11
Average number of cigarettes smoked daily
1-14
15-24
Number rate
Number rate
1 0,07
0
3 0,31
9 0,62
3 0,48
20 2,31
9 2,69
17 5,16
6 2,68
8 7,27
0,07
22
0,57
54
25+
Number rate
1
0,11
8
0,75
26
3,88
14
6,48
8 16,33
1,39
57
2,27
The relation between lung cancer mortality and cessation of smoking is shown in Table 5.
Table 5. Lung cancer deaths, rates in smokers, ex-smokers and non-smokers
Smoking habit
Number of lung cancer deaths
Current smoker
Ex-smoker for:
<5 years
5-9 years
10-19 years
20+ years
Non-smoker
Rates per 1 000 person-years
124
1,28
5
7
3
2
3
0,67
0,49
0,18
0.19
0,07
Questions re Cohort study
1.
What proportion of male physicians answered the questionnaire? How might this affect comparability of smokers
and non-smokers in the study?
2.
From table 4, compute and interpret values of relative and attributable risk for the “total” group.
3.
What do the data in table 5 imply for health education services?
82
Practical exercise
Clinical trials
The following are various scenarios illustrating clinical trials. Read the scenarios and answer the questions.
Scenario 1
A new anti-tuberculosis medication has been developed which has shown good in vitro activity and low toxicity in
phase 2 (safety) trials. A randomised control clinical trial is now being planned.
Which of the following groups would you consider to be the most appropriate controls and why? What are the
disadvantages of the groups you do not select?
No
Yes
1. Patients who receive the current standard 2-drug therapy in your clinic
If no: disadvantages
2. Patients who receive a placebo drug
If no: disadvantages
3. Patients who receive only one of the two drugs in current use
If no: disadvantages
4. Two groups, one on the current two drugs and one on placebo
If no: disadvantages
Scenario 2
In a trial of Haemophilus influenzae type b conjugate vaccine involving 60 000 infants, children born on odd dates
during a twelve month period received the vaccine in a four dose schedule plus the routine infant immunisation
schedule vaccines. Those born on even dates served as controls and received only the routine vaccine schedule.
What factors would have entered into the calculation of numbers of infants in the trial?
Was the method of allocation to vaccine and control groups satisfactory?
What alternative method might have been adopted?
How would you go about identifying cases of invasive Haemophilus disease?
What sources of bias might enter into case ascertainment?
83
Practical exercise
Advantages and Disadvantages of Different Study Designs
Complete this table by placing one or more “+” or “ –“ marks or short comments in the boxes to provide a quick
comparison of the advantages and disadvantages of these different study designs.
Experimental
study
Prospectiv
e cohort
study
Retrospective
cohort
study
Can measure disease
incidence
Can evaluate more than
one outcome from the
same risk factor
Can evaluate several
different risk factors for
the same disease
Follows the natural time
sequence of exposure and
disease
Useful for rare exposures
or risk factors
Useful for rare diseases
Useful for diseases with
long latency periods
Logistics? (eg. keeping
track of study groups?
Quality control in
method?)
Number of subjects
needed
Cost
Results available quickly
Uses existing data
84
Casecontrol
study
Crosssectional
study
Descriptiv
e (nonanalytic)
study
Practical Exercise
Sampling a population
We propose to do a study of knowledge of tuberculosis in a group who are members of a scientific society. We have
obtained a list of the members (see next page) from the register of members of the association and we will obtain a
sample of the members to administer a questionnaire.





List the frequencies of the variables gender, language, region, TB and BACT.
Select the first 8 members in the list.
List the frequencies of the same variables in the table.
Select every 5th member in the list.
List the frequencies of the same variables in the table.
Variable
All members
First 8
Every 5th
Gender
Men
Women
Don’t know
Language
French
English
Spanish
Don’t know
TB
Yes
No
Don’t know
Bact
Yes
No
Don’t know
1.
Are the three groups the same?
2.
Which of the samples is closest to the whole group?
3.
Why?
4.
What conclusion would you draw about the geographic focus of the society from the first eight cases?
5.
Why is this conclusion misleading?
6.
What will be the effect of those cases where the value is not known?
85
List of members of a scientific society
NUMBER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
GENDER
LANGUAGE
REGION
TB
BACT
MAN
MAN
MAN
MAN
MAN
SPANISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
FRENCH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
FRENCH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
SPANISH
SPANISH
ENGLISH
SPANISH
SPANISH
AML
AMN
MIE
MIE
NO
YES
NO
NO
NO
YES
YES
NO
NO
NO
NO
YES
NO
NO
NO
NO
YES
NO
YES
NO
NO
NO
NO
NO
YES
YES
YES
NO
NO
NO
YES
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
YES
NO
NO
MAN
MAN
MAN
MAN
MAN
MAN
MAN
MAN
WOMAN
WOMAN
MAN
MAN
MAN
MAN
WOMAN
MAN
MAN
MAN
MAN
MAN
WOMAN
MAN
WOMAN
MAN
MAN
MAN
MAN
MAN
MAN
MAN
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
FRENCH
ENGLISH
FRENCH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
ENGLISH
FRENCH
FRENCH
AFR
ASI
ASI
AFR
AFR
AMN
AFR
AFR
MIE
AFR
AFR
AML
MIE
AML
AML
AFR
AMN
AMN
AFR
AFR
AFR
AMN
ASI
ASI
AFR
AMN
AFR
AFR
EUR
AMN
EUR
AFR
ASI
AFR
AFR
EUR
86
NO
YES
YES
YES
NO
NO
NO
YES
NO
YES
NO
YES
NO
NO
NO
YES
NO
NO
NO
YES
NO
YES
NO
NO
NO
YES
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
NO
YES
Practical exercise
Random error and sample size
When a coin is flipped, the result, ie. heads or tails, is a random event (provided it is a fair coin, and the person flipping
it is not a trickster).
Question: If you were to conduct an experiment to test if a coin is fair, what proportion of the time would you expect
the coin to land with ‘heads up’? (ie. what is the hypothesized result of the experiment?)
Exercise: Let each person in the group conduct his or her own experiment to test a coin.
Each person flips a coin 5 times and records the number of times the coin lands heads up, then compute the
percentage ‘heads’. If there are 25 people in the group, this exercise is similar to doing the same study (with n=5
‘tosses’), 25 separate times.
Put the results in the following table:
Percent ‘heads’
0%
20%
40%
60%
80%
100%
Indicate with a mark for each person
Repeat this series of experiments, this time with each person flipping their coin 25 times. Again each persons
calculates the percentage ‘heads’ from his or her own ‘study’.
Percent ‘heads’
0-10%
11-20%
21-30%
31-40%
41-50%
51-60%
61-70%
71-80%
81-90%
91-100%
Indicate with a mark for each person
87
Record the results from the two series of experiments as frequency histograms on the following graphs.
number
Results from first series of ‘studies’ with n=5
20
18
16
14
12
10
8
6
4
2
0
0-10
11-20
21-30
31-40
41-50
51-60
61-70
71-80
81-90
91-100
61-70
71-80
81-90
91-100
Percentage 'Heads"
number
Results from second series of ‘studies’ with n=25
20
18
16
14
12
10
8
6
4
2
0
0-10
11-20
21-30
31-40
41-50
51-60
Percentage 'Heads"
Questions:
1.
What can you conclude about the most likely percentage of ‘heads’ one would obtain from a single study? Does
this ‘most likely’ value change when the sample size of the study is larger or smaller?
2.
What can you conclude about the expected ‘variation’ in results due to chance when the sample size is smaller v.
larger.
3.
If a colleague were to tell you that she tested a coins by flipping it several times and she found it came up ‘heads’
20% of the time, could she conclude that the coin is rigged?
4.
Two colleagues came to you with results of their studies on 2 different coins. They each tested different coins by
flipping them several times and they found one came up ‘heads’ 20% of the time (ie. a ‘head rate’ of 20%) and the
other came up ‘heads’ 65% of the time (a ‘head rate’ of 65%).
What is the difference in ‘head rates’ between the two studies? What is the rate ratio?
Are you confident that these differences are real? What additional information would you need to know in order
to decide in the coins are similar?
88
Practical exercise
Using sample size / power calculations in protocol development
Case studies and some recent epidemiologic studies have suggested a possible link between some occupational and
environmental exposures and idiopathic pulmonary fibrosis (IPF).
1. To address the question, “Is there an association between ‘idiopathic’ pulmonary fibrosis (IPF) and occupational
exposure to solvents or metals?” describe several possible study designs that could be considered.
2. One of your colleagues is the medical director for a large metal trades employer and you have access to health
records for all employees in the company for the past 35 years. Therefore, you have decided on a retrospective cohort
study. All employees with 1 or more years of employment since January 1, 1965 will be enrolled in the cohort. They
will be divided into exposure subgroups according to job records and company exposure information. You will
compare rates of IPF among the exposure sub-groups.
What additional information do you need in order to calculate the whether or not the available workforce is large
enough to do this kind of study?
3. Using Epi-Info, calculate the sample size needed for a cohort study given the following assumptions and decisions:
Null hypothesis: There is no difference in IPF rates between workers exposed to solvents and metals combined
compared to workers not exposed to either.
alpha=0.05 ; power = 0.80
Effect size, based on:
expected ‘baseline’ IPF rate = 6 / 1,000,000 person years
expected risk ratio = 2 (ie. risk of IPF expected to be double in the exposed group)
Sample size required: _______________
89
4. Do the same calculation several more times, varying one or more of: alpha, power, and ‘expected risk ratio’, to
complete this table:
Sample size / power estimates for a cohort study of occupational exposure to solvents and metals and IPF
assuming a baseline IPF rate (among non-exposed) of 6/1,000,000 persons per year.
Risk ratio = 2
Risk ratio=2.5
Risk ratio=3
Risk ratio=4
Power = 80%
Alpha=0.01
Alpha=0.05
Power=90%
Alpha=0.01
Alpha=0.05
5. If the baseline rate of IPF is actually lower than 6 / 1,000,000 per year, would you expect the required sample size to
be lower or higher? Check your answer by doing another Epi-Info calculation.
6. After investigating the company records, it is evident that there are only 1000 employees who have been exposed to
solvents and metals. Therefore, based on the sample size calculations, the research team decides that a cohort study is
not feasible and decides to explore the case-control design instead. All pulmonologists and pathologists in the region
are polled and they agree to submit all their IPF cases over the 2 years to the study. Based on estimates of the number
of IPF cases seen in the previous 2 years, you anticipate about 200 cases for the study.
Using Epi-Info, calculate what odds ratio a study of this size should be able to detect (with alpha=0.05 and power of
80%). What additional information about the expected study population is needed to do this calculation?
7. Compare the minimum detectable odds ratios for this kind of study, for expected baseline exposure prevalences of
2%, 20%, 50%, and 90%. What do you conclude about study power in relation to the prevalence of exposure in the
population?
90
Practical exercise
Measurement - Defining variables
Characteristics of the variables to be used in a study are key in determining what instruments will be used, the size of
the population to be studied and how the results will be analyzed.
Specifying the type of variable
The following are outcome variables frequently used in studies of lung health. Please indicate the type of each variable:
Variable
Type
Tuberculosis
FEV1 level
Tuberculin reaction
Pneumonia
Asthma severity
Smear positive TB
Lung cancer
Emphysema
ARI
The following are a number of factors or determinants often studied for their association with lung diseases. Indicate
the type of each variable:
Variable
Type
Poverty
Bacterial exposure
Tobacco smoking
Dust exposure
Gender
Age
Ethnic group
Height
Immune competence
Which of the variables listed above could be expressed in different forms (eg. as either categorical or continuous?)
Give an example of a categorical measure of ‘poverty’ and a continuous measure of ‘poverty’.
91
Definition of variables
Consider the following list of definitions of tuberculosis used in articles published in the International Journal of
Tuberculosis and Lung Disease, from the first quarter of 1999
1.
Reported patients with sputum smears positive for acid-fast bacilli in Botswana
2.
A patient with a definitive diagnosis of pulmonary (positive culture and / or clinical and
radiological diagnosis) and / or extra-pulmonary tuberculosis (positive culture) in London
3. Tuberculosis diagnosed on the basis of clinical, radiological, or microbiological results in Italy
4.
Tuberculosis confirmed by acid-fast bacilli positivity on smear or culture, and / or granulomatous
inflammation with caseous necrosis in the pulmonary biopsy specimen in Turkey
5. Isolates of Mycobacterium tuberculosis in the Netherlands
6.
Every newly-diagnosed tuberculosis patient in New Caledonia confirmed on culture in the Institut
Pasteur
7. All patients commencing treatment for tuberculosis in two districts of Uganda
Is it possible to conclude something about “tuberculosis” by simply summarizing the conclusions of all these studies?
Is it the same disease being referred to in each of these studies?
What “elements” are common to each of these definitions?
If you were going to list results or attributes from each of the studies that are comparable across all studies, how would
you do it?
92
Practical exercise
Defining disease
The following are a group of children who have come to a health centre in the rural area of a low income country:






A 4 year old child brought by his mother who has tuberculosis. The child has a cough and weight loss, a
positive tuberculin skin test and has a shadow on the chest radiograph.
A 2 year old child who has been ill for 5 months with failure to thrive and fever.
A 6-month old child with fever and a positive skin test.
An 8-month old child who lives with his uncle who has tuberculosis.
A 3 year old child who has fever and weight loss for 6 weeks and has a shadow on the chest radiograph.
A 2 year old child who, on enrolling in a child care centre, has a shadow on the chest radiograph.
1.
Which of these children has tuberculosis?
2.
Do the others definitely not have tuberculosis?
3.
How do you know? (What are the criteria you use to decide?)
4.
Which criteria have the greatest weight in considering the diagnosis?
5.
Which have the least?
6.
Why?
7.
If this was a sample from a larger group of children being studied, what difference would varying the criteria for
diagnosis make on the results of the study?
93
Practical exercise
Measuring disease
The purpose of this practical is to introduce you to the use and limitations of mortality statistics and disease rates. You
should understand how these statistics are obtained and know the most common causes of death at different ages.
You should aim to be conversant with the following terms introduced here.
Medical certificate of cause of death; Parts I and II of the certificate; Death certificate; Underlying cause of
death; International Classification of Disease (ICD) Code; The difference between numbers and rates; Crude
mortality rate; Age and cause specific mortality rates; Age standardization and Standardized Mortality Ratios
(SMRs); Incidence rates and prevalence rates.
Please complete the following questions:
1.
Study the case history which follows and the specimen medical certificate of cause of death. Complete it and
place the International Classification of Disease Code beside the one underlying cause of death.
Death certificate
International Statistical Classification of Diseases and Related Health Problems, (ICD-10)
World Health Organization 1991
Approximate
interval between
onset and death
Cause of death
I
Disease or condition directly
leading to death*
(a)………………………………………….
………………..
Due to (or as a consequence of)
(b)………………………………………….
Antecedent causes
Morbid conditions, if any,
Giving rise to the above cause,
stating the underlying
condition last
………………..
Due to (or as a consequence of)
(c)………………………………………….
………………..
Due to (or as a consequence of)
II
Other significant conditions
contributing to the death, but not
related to the disease or condition
causing it
(d)………………………………………….
………………..
……………………………………………..
………………..
……………………………………………..
……………….
This does not mean the mode of dying, e.g. heart failure, respiratory failure.
It means the disease, injury, or complication that caused death.
94
Case history
History: Four years before his final hospital admission, this 64-year old man had an admission to hospital for acute
shortness of breath. Lung function showed reduced FEV 1 with response to bronchodilator. He was
treated with inhaled beta agonists and beclomethasone. One year later, he was again admitted to
hospital and required a period of artificial ventilation for respiratory failure. Subsequently, he regular
ambulatory oxygen at home. He returned to hospital on this occasion because of breathlessness. He
started smoking cigarettes at age 16, averaged 30 per day and stopped smoking after his last
admission.
Examination: CVS – pulse 78 / min; regular. RR 50 / min; prolonged expiration with expiratory wheeze; increased
anteroposterior diameter to the chest with hyper resonance; cyanosis noted.
Other examination normal.
Investigations: Hb 11,8 g / dl; Urine – no protein or sugar; Spirometry showed reduced FEV
with reduced FEV / FVC (40%).
1
(18% of predicted)
Arterial blood gases – paO 1 markedly reduced and paCO 2 elevated.
Clinical course: Admitted to the Intensive Care Unit and intubated; following day developed fever and left shift to WBC;
tracheal secretions yielded Pseudomonas aerugenosa resistant to all common antibiotics; developed
progressive infiltration on chest radiographs; oxygenation progessively deteriorated; developed acute
chest pain, ventricular fibrillation and expired.
Post mortem: not performed.
3.
The Incidence rate of a disease is the rate per unit time at which the previously unaffected develop the
disease. The prevalence ratio of a disease at any time is the proportion of the population affected.
What will tend to raise or lower the prevalence ratio of a disease apart from its incidence rate?
How might you measure incidence and prevalence, for example, of asthma?
INTERNATIONAL CLASSIFICATION OF DISEASE 10th REVISION
Ischemic heart disease
(I20-I25)
I20
Angina pectoris
I20.0
I20.1
I20.8
I20.9
Unstable angina
Angina pectoris with documented spasm
Other forms of angina pectoris
Angina pectoris, unspecified
I21
Acute myocardial infarction
95
I21.0
I21.1
I21.2
I21.3
I21.4
I21.9
Acute transmural myocardial infarction: of anterior wall
Acute transmural myocardial infarction: of inferior wall
Acute transmural myocardial infarction of other sites
Acute transmural myocardial infarction of unspecified site
Acute subendocardial myocardial infarction
Acute myocardial infarction, unspecified
I24
Other acute ischemic heart disease
I24.0
I24.1
I24.8
I24.9
Coronary thrombosis not resulting in myocardial infarction
Dressler’s syndrome
Other forms of acute ischemic heart disease
Acute ischemic heart disease, unspecified
I49
Cardiac arrhythmias
I49.0
I49.1
I49.9
Atrial arrhythmia
Ventricular arrhythmia
Cardiac arrhythmia, unspecified
J13
Pneumonia due to Streptococcus pneumoniae
J14
Pneumonia due to Hemophilus influenzae
J15
Bacterial pneumonia, not elsewhere classified
J15.0
J15.1
J15.2
J15.8
J15.9
Pneumonia due to Klebsiella pneumoniae
Pneumonia due to Pseudomonas
Pneumonia due to staphylococcus
Other bacterial pneumonia
Bacterial pneumonia, unspecified
J41
Simple and mucopurulent chronic bronchitis
J42
Unspecified chronic bronchitis
J43
Emphysema
J43.1
J43.2
J43.8
J43.9
Panlobular emhysema
Centrilobular emphysema
Other emphysema
Emphysema, unspecified
J44
Other chronic obstructive pulmonary disease
J44.0
J44.1
J44.8
J44.9
Chronic obstructive pulmonary disease with acute lower respiratory infection
Chronic obstructive pulmonary disease with acute exacerbation, unspecified
Other specified chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease, unspecified
J45
Asthma
J45.0
Predominantly allergic asthma
96
J45.1
J45.8
J45.9
Nonallergic asthma
Mixed asthma
Asthma, unspecified
J46
Status asthmaticus
J47
Bronchiectasis
Practical exercise
Measuring disease
An international collaborative study was made of the results of treatment of new cases of pulmonary cases that were
smear positive. Of 492 cases in British Columbia, Canada, 5.1% died during the course of their treatment as compared
with 3.0% of 3,163 cases in Sudan. The same definitions for outcome of treatment were used, following the
recommendations of the IUATLD.
1.
Can we conclude that treatment in Canada is worse than in Sudan?
2.
What other information would be necessary to compare the deaths in the two countries?
3.
How would this information be used to improve the validity of the comparison?
97
Practical exercise
Measurement: using standardized instruments
The following exercises are meant to illustrate the issues associated with measurement in epidemiological studies. The
two exercises presented are simple exercises which illustrate the problems frequently encountered with
measurements and their interpretation.
The first exercise is the interpretation of chest radiographs. Four radiographs will be presented and these should be
interpreted by the participants according to a standard format, following the directions on the Radiography report
form which is appended to this exercise. Anyone can participate, regardless of qualification or previous experience.
The exercise will illustrate variation in interpretation of a commonly used test which is often considered an essential
item for diagnosis of chest diseases. The exercise is based on standard reading of chest films which has been developed
for the reading of chest radiographs for the presence of pneumoconiosis, developed by the International Labor Office.
The second exercise illustrates the use of a standard Respiratory symptoms questionnaire, in this case, an expanded
version of the bronchial symptoms questionnaire developed by the IUATLD for the study of asthma.
98
Radiography Report Form
Film number [ ]
To answer the questions, please choose the appropriate box and mark an x in the box; if you are unsure of the
answer, please choose ‘no’.
Quality of the film
no yes
1.
Adequate exposure?
2.
Proper position?
[ ] [ ]
[ ] [ ]
Parenchymal shadows
no yes
3.
Round shadows?
If yes:
Smaller than 2 millimeters?
Larger than 2 millimeters?
[ ] [ ]
[ ] [ ]
[ ] [ ]
Location:
R upper?
L upper?
R lower?
L lower?
4.
[ ] [ ]
[ ] [ ]
[ ] [ ]
[ ] [ ]
Irregular shadows?
If yes:
Smaller than 2 millimeters?
Larger than 2 millimeters?
[ ] [ ]
[ ] [ ]
Location:
R upper?
L upper?
R lower?
L lower?
[ ] [ ]
[ ] [ ]
[ ] [ ]
[ ] [ ]
[ ] [ ]
5.
Calcification?
[ ] [ ]
6.
Cavity?
[ ] [ ]
7.
Presence of thickening?
[ ] [ ]
8.
Presence of calcification?
Pleura
[ ] [ ]
99
ASTHMA QUESTIONNAIRE – Selected questions
Interviewer (initials)
Today’s date
day
STUDY NUMBER
mo
Year
SUBJECT ID NUMBER
Date of Birth
Gender:
day
mo
Male
Female
year
GENERAL RESPIRATORY HEALTH QUESTIONS
The following questions are about your lung health IN THE PAST 12 MONTHS.
Please answer yes or no. If in doubt about the answer, please answer no.
At any time in the past 12 months:
A. Have you had wheezing or whistling in your chest, when you did not have a cold?
1.Yes __
2. No __
B. Have you woken up with a feeling of tightness in your chest?
1.Yes __
2. No __
C. Have you been woken by an attack of coughing?
1.Yes __
2. No __
D. Have you been woken by an attack of shortness of breath?
1.Yes __
2. No __
E. Have you had an attack of shortness of breath that came on during the day when
you were not doing anything strenuous?
1.Yes __
2. No __
F. Have you had an attack of shortness of breath that came on after you stopped
exercising?
1.Yes __
2. No __
A. Which of the following statements best describes your breathing?
Check one:
1.
2.
3.
I rarely get trouble with my breathing
I do get regular trouble with my breathing but it always gets completely better
My breathing is never quite right
HISTORY OF ASTHMA
1. Have you ever had asthma?
1.Yes __
2.No __
IF YES TO '1', ask:
A. Do you still have it?
B. Was it confirmed by a doctor?
C. At what age did it start?
D. if you no longer have it, at what age did it stop?
100
1.Yes __
2.No __
1.Yes __
2.No __
___________years
___________years
SUBJECT ID NUMBER
OTHER ILLNESSES
A. Did you have any lung trouble before the
age of 16?
B. Have you ever had pneumonia?
if yes to B ask:
1.Yes __
2.No __
1.Yes __
2.No __
How many times have you had pneumonia?
___________times
Age at first episode:
___________years
Age at last episode:
___________years
The following questions are about some parts of your background which may be important to us in evaluating your health.
Please answer to the best of your memory.
TOBACCO SMOKING
SMOKING BY PEOPLE LIVING AROUND YOU:
When you lived at home:
A. Did your father smoke?
B. Did your mother smoke?
1.Yes ___
1.Yes ___
2.No ___
2.No ___
In your current household
C. Do any members of your current household smoke? (other than you)?
1.Yes ___
2.No ___
1.Yes ___
2.No ___
1.Yes ___
2. No ___
YOUR CIGARETTE SMOKING
D. Have you ever smoked cigarettes? (No means less than 20 packs of cigarettes or
less than one cigarette a day for one year)
IF YES TO 'D', ask:
1. Do you now smoke cigarettes? (as of 1 month ago)
2. How old were you when you first started regular cigarette smoking?
______________years
3. If you have sopped smoking cigarettes completely, how old were you
when you stopped?
4. How many cigarettes do you smoke per day now?
5. On average, for the entire time that you smoked, how many cigarettes
did you smoke per day?
101
______________years
__________________
cigarettes per day
__________________
cigarettes per day
SUBJECT ID NUMBER
FAMILY HISTORY
As some illnesses are associated with childhood and family history we would like to ask you about your family members,
and about your childhood.
Check one:
1.Yes 2. No 3.Don’t know
Was your natural father ever told by a doctor that he had:
1. Emphysema
2. Lung cancer
3. Asthma
Was your natural mother ever told by a doctor that she had:
1. Emphysema
2. Lung cancer
3. Asthma
What was your country of birth
____________________________
In what country did you spend the majority of the first 10 years of your life?
____________________________
Were these first 10 years spent in the (check one only):
Countryside or small village
Town smaller than 10,000 people
City 10,000 to 100,000 people
City larger than 100,000 people
What was your father's usual occupation?
1.
2.
3.
4.
_____________________________
What was your mother’s usual occupation? _____________________________
YOUR CURRENT JOB (or last job, if you are not currently working)
1. Who is your current employer (name of company):
_____________________________
2. What type of industry or sector is this:
_____________________________
3. What is your job?
_____________________________
4. In this job, are you exposed regularly to dust, gases, or fumes?
1. Yes
2. No __
5. In any previous job, were you exposed regularly to dust, gases, or fumes? 1. Yes
102
2. No
Practical Exercise
Interpreting Results: validity and generalizability of results
A study was undertaken to determine whether the results of treatment of smear positive cases of pulmonary
tuberculosis had changed over time. It was expected that, with the improvements in modern treatment, the results
would have improved. A similar number of cases was selected from the records of a tuberculosis ward for three
calendar periods, 1968-1969, 1973-1975 and 1982-1983. The results of treatment were as follows:
Period
Total (%)
Successful (%)
Positive (%)
Died (%)
Abandoned (%)
1968-1969
1973-1975
1982-1983
89 (100)
89 (100)
90 (100)
61 (69)
61 (69)
52 (58)
8 (9)
15 (17)
12 (13)
5 (6)
7 (8)
7 (8)
15 (17)
6 (7)
19 (21)
Statistical analysis, using the chi-square test, was performed and the p=0.12, leading the investigators to conclude that
there was no change in the response to treatment over the period studied.
1. Is this conclusion valid? (check one)
yes [ ] no [ ]
2. If no, what might lead the investigators to draw a wrong conclusion?
Factor
Category
Studied (%)
Not studied (%)
268 (100)
580 (100)
15-34
35-54
55 +
66 (25)
95 (35)
107 (40)
148 (26)
201 (35)
231 (40)
Limited
Advanced
152 (57)
116 (43)
391 (67)
189 (33)
Male
Female
190 (71)
78 (29)
410 (71)
170 (29)
TOTAL
Age group
Extent of disease
Gender
The patients chosen for study were part of the whole group of smear positive cases who had been diagnosed and
recorded in the years under study. They comprised 37% of such cases in 1968-1969, 24% of cases in 1973-1975 and
38% of cases in 1982-1983. The studied cases were not different from the whole group of patients in age (p=0.96),
gender (p=0.95) or ethnic origin (p=0.35). There was, however, a significant difference in the extent of pulmonary
tuberculosis among those studied compared with the whole population (extensive tuberculosis was present in 43% of
those studied and 33% of those not studied, p=0.003).
3.
Is the sample a valid reflection of the condition of all the patients in this locality?
Check one [ ]yes [ ] no
103
4.
Is it justifiable to conclude that the results obtained in the sample apply to the whole group of patients diagnosed
and recorded in this community?
Among the group studied, the results of treatment were not different in the two gender groups (p=0.24), nor in the
various ethnic groups (p=0.10) but were different in different age groups (p<0.001) and between those with extensive
and those with less extensive disease (p=0.001).
5.
Which factor(s) would be most likely to contribute to a wrong conclusion concerning the trend in results of
treatment?
6.
How would you control for confounding in this situation?
7.
Will this ensure that the results are valid?
Practical exercise
Interpreting results: Confounding
Please refer to the following text and tables to carry out this exercise.
In a study of the epidemiology of tuberculosis in Denmark, Horwitz (Am Rev Respir Dis 1974;104:22-31) showed that
tuberculosis was more common in men than in women and that it was much more common in those who were
unmarried than in those who had been married. The results of a study determining the relation of marital status to
tuberculosis notification in Canada from 1970-1972 is shown in table 1.
Table 1. Active tuberculosis (number of cases and average annual rate per 100 000) by gender and marital status,
Canada 1970-1972
Age
group
All
Single
No
Rate
1 122
19,5
Women
Married /
Widowed /
Separated
Divorced
3 140
21,4
703
26,3
TOTAL
4 965
21,5
Single
2 113
29,7
Married /
Separated
Men
Widowed /
Divorced
4 641
31,7
TOTAL
640
80,0
Grzybowski S. Evaluation of the Tuberculosis Problem and Control Measures in Canada. National Sanatorium
Association, 1977
104
7 394
32,8
In table 2, the same data are displayed, in this case showing the distribution by age in addition to gender and marital
status.
Table 2. Active tuberculosis by age, gender and marital status, Canada 1970-1972
Age
group
Single
Women
Married /
Widowed /
Separated
Divorced
ALL
Single
Men
Married /
Widowed /
Separated
Divorced
ALL
15-24
No
Rate
549
13,3
281
15,5
4
13,8
834
14,0
638
12,6
129
13,5
25-34
No
Rate
229
42,6
732
20,1
44
21,3
983
22,9
372
42.3
565
16,4
13
23,1
950
21,7
35-44
No
Rate
104
39,3
720
21,8
47
29,7
871
23,4
300
79,0
818
24,1
35
44,1
1 153
29,9
45-54
No
Rate
74
29,0
607
20,8
77
25,5
758
21,8
300
99.0
1 038
34,7
85
83,3
1 423
41,9
55-64
No
Rate
71
28,3
432
23,2
116
22,3
619
23,5
247
102,2
1 049
47,9
110
84,1
1 406
54.9
65+
No
Rate
95
30,8
368
32,5
415
28.7
878
30,4
256
102,9
1 042
61,9
397
96,3
1 695
72,3
1.
2.
3.
In table 1, is there a difference in notification rate according to marital status?
Which group has the highest rate (specify one group by the 3 variables)?
4.
_____________(age)__________(gender)__________(marital)
Why do you think this is so?
5.
6.
In table 2, are the conclusions you drew from table 1 valid?
Which group in the table contributes the largest number of cases?
Yes [ ] No [ ]
_____________(age)__________(gender)__________(marital)
7.
8.
Which group has the highest risk for tuberculosis?
_____________(age)__________(gender)__________(marital)
Why is there a difference?
9.
How would you modify the results displayed in table 1 to reflect reality?
105
767
12,7
One decade later, we further examined this association in the city of Vancouver. The results are presented in table 3.
10.
In table 3, are the conclusions you drew from table 2 valid?
Yes [ ] No [ ]
11.
What is the cause of the difference in rates between ever married and never married men?
Table 3. Active tuberculosis(per 100 000 per year) in Vancouver 1980-1982 in adult Canadian-born men according to
socioeconomic status and marital status.
Socioeconomic level
Ever married
Number Rate
Never married
Number Rate
TOTAL
43
22
42
37
High
Middle
Low
3
21
19
3
22
299
5
13
24
12
20
326
Enarson DA, et al. Am J Epidemiol 1989;129:1268
106
Practical exercise
Interpreting results: Standardization of rates
The following table gives the situation concerning prevalence of significant skin reactions to tuberculin in residents of
Honduras and of Canada, along with their populations:
Prevalence of significant tuberculin reactions in Honduras and Canada
population
Age
Canada
cases rate
(%)
population
Honduras
cases
Rate
(%)
TOTAL
27,000,000
8,100,000
30
3,510,000
1,072,275
31
0-14
1,890,000
0
0
1,120,000
43,971
4
15-24
5,130,000
0
0
910,000
115,379
13
25-34
6,210,000
0
0
700,000
295,400
42
35-44
4,320,000
540,000
13
390,000
262,681
67
45-54
3,780,000
1,890,000
50
210,000
183,204
87
55-64
3,510,000
3,510,000
94
110,000
101,640
92
65+
2,160,000
2,160,000
100
70,000
70,000
100
Calculate the rate of tuberculin skin reactivity in the two populations, standardized for age and enter into the
table.
What is the explanation of the difference between the crude rate and the standardized rate?
What are the advantages of the standardized rates over the crude rates?
What are the disadvantages of presenting only the standardized rates?
107
Practical exercise
Role of statistical testing in research
from The Epidemiology of tuberculosis in gold miners with silicosis. Cowie RL. Am J Respir Crit Care Med 1994;
150:1460-1462.
These investigators carried out a 7 year prospective study of 1153 South African gold miners. At the start of the study,
818 of the miners had silicosis and 335 did not. Each miner was tested for active tuberculosis each year for the 7 years
of follow-up. The investigators were interested in knowing if miners with silicosis were more likely to develop
tuberculosis than those without silicosis.
Results (at the end of 7 years)
Silicosis
p-value
No
Yes
number studied
335
818
pulmonary TB (n)
extra-pulmonary TB (n)
total TB (n)
20
3
23
128
27
155
pulmonary TB (%)
extra-pulmonary TB (%)
total TB (%)
6.0%
0.9%
6.9%
15.6%
3.3%
18.9%
extra-pulmonary TB /
total TB (%)
13.0%
17.4%
total TB (% per year)
1.0%
2.7%
1.
What do you conclude from these results with respect to the rates of pulmonary and extra-pulmonary
tuberculosis among these two groups of miners?
2.
Do you think the groups differ with respect to the proportion of total tuberculosis that is extra-pulmonary?
3.
Recalculate the proportions of extra-pulmonary to total TB for the miners without silicosis, if there were 1 fewer
case (and 1 more case) of extra-pulmonary TB in that group (ie. 2 or 4 cases instead of 3). Does this change your
answer to question 2?
4.
In what way would statistical testing help you answer these questions?
108
Practical exercise
Describing results
Microbial inciters of acute asthma in urban Nigerian children
Gbadero DA, Johnson ABR, Aderele WI, Olaleye OD. Thorax 1995; 50:739-745.
Objective: to determine how often acute exacerbations of asthma in children are associated with acute respiratory
infection, to identify the associated pathogens, and to proffer appropriate therapeutic suggestions.
Study population:
 subjects were recruited from asthmatic children attending the Pediatric Asthma Clinic of the University College
Hospital over a 16 month period
 children were included in the study if they were previously diagnosed as having asthma, and visited the clinic with
an acute exacerbation with duration of symptoms prior to visit of less than 48 hours; only 1 episode was recorded
per child
Methods:

clinical features recorded included: antecedent or concomitant symptoms; household / socioeconomic factors;
frequency of previous asthma exacerbations; anthropometric measurements
 laboratory measures included: chest radiograph; hematology, serology and cultures (venous blood); virological
studies (nasopharyngeal aspirate)
What is the name of this study design?
Sample data table
subject age
id
(yrs)
sex race
date weight height virus
of
(kg)
(cm)
identified
visit
(yes/no),
if yes:
type
bacteria xray
rhinoridentified inflamm? rhoea?
(yes/no), yes/no
yes/no
if yes:
type
fever?
yes/no
sore
crowding ..
throat? at home?
yes/no yes/no
..
1
2
3
4
5
6
7
.
.
86
Discuss how to summarize the information collected (don’t focus on statistical analyses, rather
think about how to summarize the information). Prepare 1 or 2 tables (without numbers, just
headings for the rows and columns) to describe the information collected for the study.
109
Hints:
1. Consider the study objectives. What is the main question being asked?
2. Are there two groups (or subgroups) being compared (this may not be explicit).
3. What is the health outcome being investigated? What risk factors were measured?
4. What is/are the main comparisons needed to answer the study questions?
5. How can you display the results in order to show the comparisons clearly?
110
Practical exercise - 2
Describing results
Risk Factors for Rifampin Mono-resistant Tuberculosis
R. Ridzon, C. G. Whitney, M.T. McKenna, J. P. Taylor, S.H. Ashkar, A.T. Nitta, S.M. Harvey, S. Valway, C. Woodley, R.
Cooksey, I. M. Onorato; Am J Respir Crit Care Med, 157, 1998, 1881-1884
Objective: to investigate the relationship between rifampin mono-resistant tuberculosis and use of rifabutin and to
identify other risk factors for rifampin mono-resistant tuberculosis among patients with and without HIV infection
Study population: multi-centre study (9 US cities)
 cases (age 20+) selected from cases of tuberculosis reported to CDC's national surveillance database from 1993 to
1995 with a first M. tuberculosis isolate resistant to rifampin and without resistance to isoniazid, ethambutol, or
streptomycin.
 2 matched controls 20 yr of age or older were chosen per case from tuberculosis cases with isolates demonstrating
susceptibility to isoniazid, rifampin, ethambutol, and, if tested, streptomycin. Controls were the two next reported
patients who matched the case by city of residence (or county, if from a rural area), HIV status, age within 5 yr and
start of tuberculosis treatment within 3 mo.
What is the name of this study design?
Methods: Medical records were reviewed, including tuberculosis clinic records, hospital records, private provider
records, and HIV clinic records (when applicable). Information collected included demographics (age, sex, race, birth
place), history of homelessness, incarceration, HIV status, prior tuberculosis, diarrhea, and medications taken at the
time of and prior to the current diagnosis of tuberculosis.
Sample of selected results (fabricated!)
subject id
rifampin
resistant
yes
no
no
no
yes
yes
no
no
no
no
1
2
3
4
5
6
7
8
9
10
.
.
190 no
age
33
56
46
40
68
21
63
30
39
35
sex
race
m
m
m
f
m
f
m
m
m
m
70 f
b
a
w
w
h
a
h
h
w
a
home
less
y
y
n
n
n
y
n
y
y
n
birth
place
US
US
US
US
US
China
US
US
S.Afr.
US
HIV status prior tb prior
O.I.
p
n
y
p
n
y
n
n
n
n
n
n
n
y
n
n
n
n
n
n
n
p
n
n
p
n
y
n
n
n
b
y
US
n
n
111
n
prior
jail
diarrhea
.
rifabutin
use
.
.
.
.
.
Practical exercise
Critical review of a publication
Please read the paper provided and then think about the answers to the questions.
1.
What was the main aim of the study?
2.
What type of study was undertaken?
3.
Was this appropriate to the objective and could any other design have equally well been
used?
4.
Were there any important flaws or weaknesses in the study design or its execution?
5.
How might these (if any) have affected the results and how might they have been avoided?
6.
What was the main statistical finding?
7.
Were the data appropriately analyzed and adequately displayed?
8.
If not, what further or alternative analysis could you have done?
9.
What were the study’s main conclusions?
10.
Do you think the conclusions were justified on the evidence presented?
112
ANNEXURES
OUTBREAK INVESTIGATION
(Trigger & Response Mechanisms)
In
IDSP
113
Level 1 (ANM/ MPW)
Serial
no
1.
Syndrome
Trigger event
Action taken
Acute watery stools
More than 5 cases in
1000 population
2.
A ) Fever < 7 days
duration
1. Treat with appropriate antibiotics.
2. Treat with ORS
3. Refer to PHC if dehydration is
severe.
4. Inform MO PHC
5. Collect water samples and send to
PHC for analysis.
6. OT testing
7. Check TCL stock (bleeching
powder)
8. Train the local person about
chlorination of water.
9. IEC for Community awareness about
safe water and personal hygiene.
5 cases in 1000
population.
1.Slides for MP with presumptive /RT
for malaria
2. Inform MOPHC.
3. IEC for community awareness.
b) With rash
Even single in the
village
1. Collect slide for MP.
2. Refer the case to PHC
3. Inform MOPHC
4. Give vitamin A
5. Give paracetamol.
6. Check immunisation
7. Surveillance for Aedes Egypti
Larvae in the house.
a. Containers
b. Coolers, etc
c) Altered
consciousness
Even single case in
the Village
1. Collect slide for MP.
2. Refer the case to CHC/DH
3. Antipyretics
4. Inform to PHC
5. Vector surveillance
6. IEC
a) Only fever
114
d) Fever with
bleeding
Even single case in
the Village
e) Fever with
convulsions
Even single case in 1. Refer the case to CHC/DH
the village above 5 2. Inform to PHC
years of age group
3. Vector surveillance
4. IEC
B) Fever more than
7 days
More than 2 cases in 1. Give paracetamol.
1000 population
2. Collect slide for MP.
3. Give anti malarial treatment.
4. Inform to PHC.
5. OT testing of drinking water.
6. Collect water sample and send it to
PHC for analysis.
7. Check TCL stock.
8. Train local person about water
Chlorination.
9. Community awareness about safe
water and Personal hygiene.
3.
Jaundice
4.
Unusual event
More than 2 cases in 1. Refer to PHC
1000 population.
2. Inform MOPHC
3. Search for antenatal cases with
jaundice in 2nd/3rd trimester.
4. Collect water samples for analysis
and send it to PHC 5. OT testing.
More than 2 deaths 1. Inform MOPHC
or
2. Community awareness
hospitalization
115
1. Refer the case to CHC/DH
2. Inform to PHC
3. Vector surveillance
4. IEC
Level 2 Medical Officer Level (PHC/CHC)
Serial
no
1.
Syndrome
Trigger event
Action taken
Acute watery stools
>5 cases in 1000
population for
some geographical
area










2.
Typhoid
More than 2 cases
for
some geographical
area







3.
Viral hepatitis
2 cases or more of
jaundice from one
geographical area.












116
Verify the information from ANM.
Confirmation of the outbreak.
Active search of cases with standard
case definition.
Standard case management.
Stool sample collection for Cholera.
Ensure safe water supply.
Inform district authority and ask for
help SOS.
IEC.
Documentation.
Ensure buffer stock.
Verify the information
from ANM
Confirmation of the
outbreak
Active search of cases with standard
core definition
Stool sample collection
Standard case management
Ensure safe water supply
Inform district authority and ask for
help SOS
IEC
Documentation
Ensure buffer stock
Blood culture for S typhi.
Clinical verification.
Standard case management.
Active search of cases.
Ensure Safe Water supply.
Stool samples for virus isolation.
Serological investigation.
Active search for 2nd/3rd trimester
cases with jaundice and keep them
under observation with referral to
district hospital SOS.
Investigation of water Treatment
4.
5.
Measles
Japanese
Encephelitis

Even a single
suspected case










Even a single
suspected case.







7.
DF/DHF
Even a single case
of suspected
DF/DHF from a
community of 1000
population.










8.
Malaria
Even single case
is found malaria
+ ve in an area
117



Plant/pipeline Leakages.
Verify the case through clinical
manifestation.
Send samples for laboratory testing.
Standard case management.
Active search of cases.
Ring vaccination.
IEC
Vitamin A.
Verify the information.
Clinical confirmation.
Standard case management.
Active search of cases with standard
case definition.
Vector surveillance and control.
IEC
Vaccination as a preventive
measure.
Subsequently inform to higher
authority.
Isolation of virus.
Sero-diagnosis
Referral of serious cases to district
hospital.
Verify the information.
Suspect if clustering of fever cases
with M.P. negative slides are found.
Confirmation of outbreak.
Standard case management.
Active search of cases with standard
case definition.
House-to-house vector surveillance
for A.. Egypti Larvae.
Fogging/spraying if necessary.
Inform the DHO.
IEC
Empty the coolers, vessels and keep
them dry for 24 hours at least once in
a week.
Remove garbage. (containers etc.)
Mass survey for fever cases.
Microscopic examination within 24
hours
where malaria
was not present
for minimum
three months.
SPR rise more
than double over
last three months.
Single death from
malaria (clinical
/microscopically).
Single PF case of
indigenous origin.







9.
Unusual
syndromes
causing death or
hospital admission
Hospitalization or
death of minimum
two cases of similar
illness from same
geographical area.









118
Start CRT to all fever cases/all
contacts of +ve cases and all
migratory population. (in case of
single PF case of indigenous origin is
found)
Focal spraying with synthetic
pyrethyroid
Fogging daily X 3 days followed by
biweekly for 3 weeks.
Larvicidal application
Elimination of mosquitogenic places
by tempting of water tables, land
filling, channelizing the drains.
Activate DDC/FTD
Involve local bodies and community
by IEC.
Daily surveillance for 3 to 4 weeks.
Verification of the rumor.
Clinical verification of cases.
Basic Life Support and emergency
medical care.
Refer to appropriate hospital if
necessary.
Active search of cases.
Autopsy and preservation of body
fluid and tissues of vital organs for
laboratory diagnosis.
IEC to avoid panic.
Reporting to the higher authority.
Level 3 District Level/Medical College
Serial
Syndrome
Trigger event
no
1.
Acute watery
>5 cases in 1000
diarrhea/cholera.
population from
same geographical
area.
2.
Typhoid
More than 2 cases
for some
geographical area
3.
Viral hepatitis
2 cases or more of
jaundice from one
119
Action taken
1 District Nodal Officer Verifies the
information from Medical Officer PHC/CHC
2 Confirmation of the outbreak with the help
of data analysis
3 Analysis of laboratory sample if any.
4 Rapid Response team
Visit to the site
 Confirm the outbreak

Std. Case management

Active search of cases with
standard case definition
 Stool sample collection
 Ensure availability of
essential drugs and establish
Depot center.

Ensure safe water supply.

Inform State authority and ask
for help SOS.

IEC.
 Documentation.

Feedback
1 District Nodal Officer Verifies the
information from Medical Officer PHC/CHC
2 Confirmation of the outbreak by data
analysis
3 Analysis of laboratory sample if any.
4 Rapid Response team Visit to the site.
 Confirm the outbreak

Std. Case management

Active search of cases with
standard case definition

Ensure safe water supply

Inform State authority and ask
for help SOS

IEC

Documentation

Feedback

District Nodal Officer Verifies the
information from Medical Officer
geographical area.











4.
Measles






Even a single
suspected case






6.
Japanese
Encephelitis




Even a single
suspected case.
120
PHC/CHC
Confirmation of the outbreak
by data analysis
Analysis of laboratory sample if any.
RRT investigation to confirm
epidemic.
Standard Case Management.
Find out source of infection .
Active search of cases.
Ensure safe water supply.
Stool samples for virus isolation.
Serological investigation.
Active search for 2nd/3rd trimester
cases with jaundice and keep them
under observation with referral to
Medical college hospital SOS.
Investigation of water Treatment
Plant/ pipeline Leakages.
Inform State authority and ask
for help SOS
IEC
Documentation
Feedback
District Nodal Officer Verifies the
information from Medical Officer
PHC/CHC
Confirmation of the outbreak by data
analysis
Analysis of laboratory sample if any.
RRT investigation to confirm
epidemic.
Ring immunization and
effective containment.
Send samples to reference
laboratory.
Standard management of complicated
cases.
IEC
Vitamin A prophylaxis
Feedback
District Nodal Officer Verifies the
information from Medical Officer
PHC/CHC











7.
DF/DHF
Even a single case
of suspected
DF/DHF from a
community of 1000
population.
















121
Confirmation of the outbreak by
data analysis
Analysis of laboratory sample if any.
RRT investigation to confirm
epidemic.
Clinical confirmation.
Standard case management.
Active search of cases with standard
case definition.
Vector surveillance and control.
IEC
Vaccination as a preventive
measure.
Subsequently inform to higher
authority and ask for help sos.
Laboratory specimen to reference
laboratory for Virus Isolation.
Sero-diagnosis
IEC
Documentation
Feedback
District Nodal Officer Verifies the
information from Medical Officer
PHC/CHC
Confirmation of the outbreak by
data
analysis
Analysis of laboratory sample if any.
RRT investigation to confirm
epidemic.
Standard management of complicated
cases.
Active search of cases with standard
case definition.
Intensified Vector surveillance housetohouse
Foggy/spraying if needed.
IEC
Empty the coolers, vessels and keep
them dry for 24 hours at least once in
a week.
Sero-diagnosis
IEC
8.
Malaria
Even single case
is found malaria
+ ve in an area
where malaria
was not present
for minimum
three months.
SPR rise more
than double over
last three
months.
Single death
from malaria
(clinical/microsc
opically).
Single PF case
of indigenous
origin.

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9.
Unusual
syndromes
causing death or
hospital admission
Hospitalization or
death of minimum
two cases of similar
illness from same
geographical area.
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122
Documentation
Feedback.
District Nodal Officer Verifies the
information from Medical Officer
PHC/CHC
Confirmation of the outbreak by
data
analysis
Analysis of laboratory sample if any.
RRT investigation to confirm epidemic
Mass survey for fever cases.
Microscopic examination within 24
hours
Start CRT to all fever cases/all
contacts of + ve cases and all
migratory population. (in case of
single PF case of indigenous origin is
found)
Focal spraying with synthetic
pyrethyroid
Fogging daily X 3 days followed by
Biweekly for 3 weeks.
Larvicidal application
Elimination of mosquitogenic places
by tempting of water tables, land
filling, chanalizing the drains.
Activate DDC/FTD
Involve local bodies and community
by IEC.
Daily surveillance for 3 to 4 weeks.
District Nodal Officer Verifies the
information from Medical Officer
PHC/CHC
Confirmation of the outbreak by
data
analysis
Analysis of laboratory sample if any.
RRT investigation to confirm
epidemic
Basic Life Support and emergency
medical care.
Refer to appropriate hospital.
Active search of case.
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123
Autopsy and preservation of body
fluid and tissues of vital organs for
laboratory diagnosis.
IEC to avoid panic.
Reporting to the higher authority.
Documentation
Feedback.
ANNEXURES
For
Outbreak Investigation
And Response
1.
2.
3.
4.
RUMOUR REGISTER
SAMPLE INITIAL REPORT
LINE LISTING OF CASES
INTERIM OUTBREAK REPORT
124
HANDOUT -1
RUMOUR REGISTER
Record verbal or written information from lay reporters (community representatives,
Anganwadi workers, teachers) about suspected outbreaks, rumours, or reports of
unexplained events.
Date of
notification
Suspected Disease
(signs and symptoms if diagnosis
is not available)
Location
No. of
cases
125
Date of 1st
case
No: of deaths
Treatment
centers
Comments
HANDOUT -2
SAMPLE INITIAL REPORT
(For outbreaks caused by water borne diseases)
(to be submitted within a day of the first team reaching the outbreak site)
1. Name of the affected village/town/city
2. Name of the reporting center
Sub-centre / PHC / RH / CH / GH / Corpn. Hosp.
3. Block / Districts
4. Population of the affected town / area
5. Date of onset of outbreak
6. Date of reporting
7. Name of the Informant
8. Total attacks reported till date
9. Total deaths reported till date
10. Main symptoms of the patients
11. Presumptive / Final Diagnosis
12. Probable cause of the outbreak
13. Spot map
14. Water supply information


Water supply scheme / wells / bore-wells / others
General / Private
126
15.
Sr. No.
Name of the medicine
stool
1
Furazolidine
2
Tetracycline
3
O.R.S. packets
4
Ringer’s lactate
5
I.V. Normal saline
6
IV sets
7
Bleaching Powder
8
Halogen tablets
Approximate Stock
samples collection (during the outbreak)
16. Stock position
127
Date of
9
Tab. Co-trimoxazole
17. Details of any control measures instituted:
Sr. No.
Control Measures
1
Place of the treatment
2
No. of the attending staff (MO, Nurses)
3
Camp hospital opened, if yes details
4
Date of starting active surveillance
5
Chlorination of water sources started, if yes,
details thereof
Water samples collected? If yes, details
thereof.
6
Action taken
Date:
Signing Authority
Similar ones for Vaccine preventable diseases and Vector borne disease may be made. In the former,
details of immunization status need to be included, while in the
latter, details of vector control measures need to be included.
128
HANDOUT -3
LINE LISTING OF CASES
no.
name
age
sex
fathers
name
address
date
of
onset
of
illness
symptoms
&
signs
treatment
received
lab
reports
outcome
exposure
to
risk factor
comments
Key to the form
No: serial number
Name: of all the suspected cases
Age: if there are small children involved, then better to record the age in months for ALL
Father’s name: if identification is a problem through name only
Address: as detailed as possible so that later there is no problem while mapping
Date of onset of symptoms: as accurate as possible as this gives an idea of the incubation period.
Symptoms and signs: list the common symptoms and signs in each column. It should be filled as yes
and no
Treatment received: the details as well as the place at which it was received. Details include the
medicines received
Lab reports: the details as and when they are available. Till then, the samples taken should be filled into
this column
Outcome: whether the person is alive and well or whether the person is dead or whether the person is
still sick
Exposure to risk factors: Initially this may not be clear, but as risk factors are identified, exposure to
them needs to be checked.
This may necessitate going back to the initial cases and checking.
Comments: any comments related to the outbreak
129
HANDOUT -4
INTERIM OUTBREAK REPORT
(FOR OUTBREAKS DUE TO WATER BORNE DISEASES)
(Report to be submitted by RRT within 7 days of reaching the spot)
1. RRT members
2. Name of the affected towns / villages / Blocks / Districts
3. Name of the sub-center(s) / PHC(s) affected
4. Is it a high-risk area?
5. Details of staffing in the affected institutions, including vacancy positions
Prior to the outbreak, existing situation now.
6. Details of the geographic location of the area, preferably supported with
a map, giving details of
the population – both affected and not affected
the institutions and distances involved
the water sources etc
any other risk factors
7. Date of onset of first case
8. Date of reporting of first case
9. Date of onset of last case reported
10. Date of detection of last case reported.
11. How was the outbreak detected?
130
11.Main symptoms and signs
12. Epidemic curve
13. Details of possible transmission – preferably graphically.
131
15. Probable diagnosis
16. Lab diagnosis
17. Information of Laboratory Examination
132
133
23. Cause of the outbreak (Detail information of the reasons of water contamination)
24. Details of containment measures taken
25. Details of the mortality audit –
1. Name of the diseased :
2. Age : Sex :
3. Complete address :
4. Symptom :
5. Date of onset illness :
6. Treatment received from whom and where :
7. If admitted, and date and time of admission :
8. Date and time of onset of treatment :
9. Condition of the patient at the time of the
admission:
10. Details of the treatment :
11. Date and time of death :
12. Place of death (Home / Hosp, etc.) :
13. Whether stool sample was taken ?
(If yes, result)
:
14. Medical Officer’s opinion :
Similar reports can be developed for the VPD and VBD.
Similar format can be used for the Final report.
134
HANDOUT -5
REPORT WRITING
STEPS OF REPORT WRITING
A standard report may contain up to 7 parts:
 Introduction
What is the problem you are investigating and why is it important?
 Background
What is already known about this and similar problems? What existing information
and theories are you going to use to solve the problem?
 Procedure
What experimental steps have you taken to solve the problem?
 Experimental data
What raw data have you obtained?
 Calculations and results
How did you transform the raw data into the data necessary to solve the problem?
Show the calculations you performed on the data you collected.
 Conclusions
What conclusions can you draw from your results? Discuss any new questions that
were generated by your experiments.
 References
Bibliographical citations of all published work from technical journals or books that
you used in your study. If a theory or method is not your own, but was borrowed
from another researcher’s work, you must acknowledge this by referring the reader
to the paper or book in which you found the information.
Source: www.chemcollective.org/oldlab/report.doc
Introduction
A report is a presentation of facts and findings, usually as a basis for
recommendations; written for a specific readership, and probably intended to be kept as a record.
When some people write a report, that's all they do: write. But the really successful writers only
spend part of their time doing this, and then only towards the end. Before that, they are planning
their report - thinking about its purpose, and who is going to read it; deciding what to put in it, and
fitting it into shape. And even when they're finally writing it, they'll probably spend just as much
time thinking about how best to present their ideas, as actually putting them onto paper.
135
This guide draws on the experience of such writers, and describes their step-by-step approach, the
six stages being:
Purpose and reader
Materials and structure
Style and presentation
The guide has been devised for you to use as a memory aid once you are back at your desk, and
working on your next report. We hope that you'll find it helpful, and that you -and your readers will benefit.
Purpose and Reader
Experienced writers always allow plenty of time for these - the first two stages in report writing,
even when they are working against the clock. They know that once these are clear in their minds,
they'll save themselves hours of work and worry later on.
1 Defining the purpose
First, the purpose - the major aim - the reason why you are writing the report at all. This will
determine what kind of report you write.
a) Factual report
For example, it may be to inform - when, say, there's been an accident, or a new programme of
work. What's needed here is a factual report - a straightforward statement of the facts - to give
people an accurate record.
b) Instructional report
Or, it may be to explain - for example, when some change is introduced, like a revised appraisal
system, or a new job evaluation scheme. Here you write an instructional report - a step-by-step
description - to tell people about the new procedures.
c) Leading report
Lastly, it may be to persuade - when you are trying to sell your ideas. This kind is usually called a
'leading' report, because you are leading the reader towards making a decision - the one you want
him or her to make.
Once the major aim has been defined in this way, subsidiary aims will fall into place -thus, we
inform in order to explain, and inform and explain in order to persuade. And usually the result will
be a leading report - which is often the most difficult to write, because it has to motivate the reader
to do something at the end.
2. Identifying the reader
136
But who is the reader? What do we really know about them? Often, they are just a dim and
shadowy figure in the mind, but we can usually get a clearer picture by asking three questions:
a) What does the reader know?
Two common mistakes in report writing are to overestimate a reader's knowledge-and blind them
with science, or to underestimate it - and bore them to tears. We must always try to discover how
much the reader knows already, so that we can communicate at their level of knowledge.
b) What are the reader's attitudes?
However good our ideas, they may get thrown out if we don't take account of these, the reader’s
special interests, likes, and dislikes. The truth has many faces, and it is only sensible to feature the
one most likely to appeal to them.
c) What does the reader really want?
The reader is rarely a passive recipient of our report, to be swayed this way and that by our
arguments. We'll need to find out just what their hopes and expectations are. Then we shall know
what we're up against, and can prepare our case accordingly.
Sometimes, it is difficult to answer these questions, especially when writing for a varied readership.
In such cases, aim for the important reader - that is, the most important to you - but without
offending others. Some are probably only on the distribution list anyway for reasons of prestige or
courtesy, or because no-one remembered to cross them off. They will probably be quite happy just
to read the opening summary (see p.7).
3 Setting the objective
Matching the purpose to the reader, we are now ready to set our objective. In other words, what
do we want the reader to think and do after reading our report? Here is an example:
To persuade the managing director to authorize a proposed system of flexible working hours.
Notice the words 'to persuade' and 'to authorize'. They show that we must produce a logical and
consistent case: one that will spur our reader to positive action. Also, once we have set the
objective, we can usually anticipate the likely problems in meeting it e.g.:
a) Knowledge
The managing director is a busy man, and has never heard of flexible working hours. We’ll need to
give him ample background information, and define any technical terms as we go along.
b) Attitudes
He is a stickler for discipline and good timekeeping. We'll have to convince him that the scheme
won't be a licence for lateness, but that, on the contrary, timekeeping might actually improve.
c) Wants
137
According to the grapevine, he is worried just now about rising costs. So we'll need to stress how
flexible working hours would actually save him money, even if this means playing down other
benefits.
Arriving at an objective like this is the most important step in writing any report. Sometimes the
process will even show that a report is not necessary at all, and that the objective can best be met
in some other way - in which case, you will have saved yourself a great deal of time and trouble.
Materials and structure
Most writers imagine that their report will be the major event in the reader's day, when, in reality,
the poor fellow is awash with reading matter, drowning in facts, figures, and opinions. What he
wants is easily-digested information, and then only enough to help him reach a decision. So the
content of our report, and its structure, must be very carefully planned.
1 Selecting our material
The two golden rules to follow when deciding what to put into a report are:
a) Simplify, and be ruthless about it. Reject the irrelevant, agonize over the doubtful, and make
sure you've got the essential.
b) Justify your conclusions with facts, and state their sources. Build the facts into a logical and
consistent case, so as to lead the reader to the same conclusions as your own.
2 Planning the structure
The facts themselves should therefore be a set of directions, which will lead and guide your reader
along a route. This route has to be planned before you write your report, perhaps as follows:
Turn a large sheet of paper sideways, and work across it. Work horizontally, so that you can see the
whole plan of your report at one time (see p.6).
First, divide it into major sections. Every subject can be broken down in this way, and the headings
will probably become the headings in your report.
Make a list under each heading of all the points you would like to mention. Note the information
that you'll need to support them.
Now mark the most important points, the essential steps in your reasoning.
Next, mark the least important ones, points your reader would find irrelevant. These you will
probably reject.
138
The points that remain-the unmarked ones, are the 'doubtful'. Some you may want to use as
examples, or to include in the appendices. But some of these also you'll reject.
Lastly, arrange the points in a final, logical sequence, so as to meet your objective. Some people
write them out on scraps of paper at this stage, and shift them around until they get the order
right.
A plan like this will show you what information you'll need for the body of the report, and what
should go in the appendices. Once written, you draw out your conclusions and add your
recommendations. And last of all, you add your title page, summary, contents list, and introduction.
These eight items make up the conventional structure of a report, dealt with in more detail below.
3 Rules and guidelines
The following rules and guidelines relate to the conventional structure of a report. Some
organizations lay down their own ('House style').
a) Title page
This normally carries the title, sub-title if any, date, author's name and position, and distribution
list. It may also carry a reference number or other classification (eg, confidential). But don't
overcrowd the page: a clear, simple layout is always the best.
b) Summary
A necessity if the report is a long one. It gives busy people the gist of the report without their
having to read it all; but if attractively written, it may whet their appetite, and stimulate them to
read the whole thing.
c) Contents list
The contents of short reports may be shown on the title page - or not at all. More extensive ones
should always have a separate page, listing the major sections or chapters, sub-sections if any, and
appendices, and giving their page numbers. It should be laid out clearly so as to show the
relationship between them.
d) Introduction
This gives the background to the report, and shows why it was necessary. It usually states the
objective of the report (in formal terms), who called for it, and the scope and treatment. The
shorter it is, the better.
e) Body of the report
This contains your detailed facts and findings, shows how they were arrived at, and indicates the
inferences to be drawn from them, all in accordance with your horizontal plan (p.5).
f) Conclusions
Here you draw out the main points of your report and present a considered judgment on them.
139
g) Recommendations
Finally, set down any recommendations, relating them clearly to what has gone before. In a good
report, the reader is carried along by the argument, so that by the time here aches the end, he'll
need no further convincing.
h) Appendices
Some reports need detailed supporting information, or perhaps information that only some readers
need. All this goes in the appendices.
In some cases you may also need to include:
j) Bibliography and/or References
This lists both the books and articles consulted as a basis for the report, or those you want to
suggest as further reading - or both. Make clear which they are.
k) Glossary or Nomenclature
This can be a help if your readers include non-experts as well as experts. When writing on a
specialist subject for non-experts alone, define any technical terms as you go along.
Style and presentation
Having dealt with the four essential stages in planning our report, we can now look at the two
essential aspects of writing it.
1 Style
This is how you write - how any individual writes, so as to convey your thoughts to other people.
But problems may arise, especially if you try to evaluate each word or sentence as you write it.
'That's silly,' you say, or, 'That won't work,' and you end up by blocking the natural expression of
your ideas.
To overcome these problems:
a) Write the first draft to yourself. Just as it comes. Don't evaluate what you are writing: simply
break the spell of that blank, white sheet of paper.
b) Then edit your draft, reading it through the eyes of your reader. In particular:
Clear up any clichés and obvious ambiguities, e.g., '. . . the flooding was caused by the liquidation of
the contractors working on the sewage system.'
Substitute short, simple words where appropriate, e.g., 'start' for commencement', and ‘end' for
'termination'.
140
Choose words familiar to your reader. Technical terms are a useful shorthand to use with fellow
specialists, but simply cloud the issue for anyone else.
Use active, rather than passive verbs, eg, 'The Board has approved this project,' rather than
'Approval has been given by the Board for this project.' This is a contentious issue– most scientific
reports tend to be written using the passive form. Ask about the
'House Style' if in doubt.
Follow these rules, and your problems will diminish. In fact, choose the right words, and you’ll find
that they have a happy knack of arranging themselves.
2 Presentations
You may need to use tables, graphs, bar charts, or other diagrams. This is a subject in itself, so ask
your local librarian for some helpful books. (The standard work, but expensive, is Diagrams, by A.
Lockwood, published by Studio Vista.)
Also, remember the old journalistic principle: solid blocks of type weary the eye. Set your report
out generously. Use wide margins; space out paragraphs; and indent subheadings. It will make all
the difference.
Helpful books
General reference material
Get to know your local reference library and the librarians in charge. They are used to handling
every type of enquiry, and will help you to draw on a wealth of immediately available reference
material, in the shape of encyclopaedias, dictionaries, directories, handbooks, year-books,
statistical returns, abstracts, etc. They are also able to draw on the help of other, specialist, libraries
and information services, many of which are not known to the general public.
Books on report writing
For anyone wanting to know more about the actual job of report writing, we recommend the
following:
1. How to write reports John Mitchell. (Fontana/Collins)
2. Report writing A. E. Derbyshire. (Edward Arnold)
3. Writing technical reports Bruce M. Cooper. (Pelican)
4. The technique of clear writing Robert Gunning. (McGraw-Hill)
141
A writer's friends
There are also a number of books which should be by your side whenever you write a report. We
have limited the list below to those in paperback or inexpensive hardback editions:
1.Chambers Twentieth Century Dictionary or
2.The Concise Oxford Dictionary (or ideally both)
3.Roget's Thesaurus of English Words and Phrases (Longmans)
4.Authors' and Printers' Dictionary F. Howard Collins. (OUP)
5.The Complete Plain Words Sir Ernest Gowers. (Penguin)
6.Fowler's Modern English Usage (OUP)
7.Usage and Abusage - a guide to good English Eric Partridge. (Penguin)
142
HANDOUT -6
How to Review an Article
Guidelines for Reviewing
Here are nine things you should consider as you examine the manuscript and write your review:
Look for the "intellectual plot-line" of the article. You can do this from first skimming through
the manuscript and then giving it a once-over read. As you do this, ask the five major questions
that are central to the research review process:
1. What do the researchers want to find out?
2. Why is that important to investigate or understand?
3. How are the researchers investigating this? Are their research methods appropriate and
adequate to the task?
4. What do they claim to have found out? Are the findings clearly stated?
5. How does this advance knowledge in the field? How well do the researchers place their
findings within the context of ongoing scholarly inquiry about this topic?
Look at the organization of the article. Can you find answers to the above questions quickly
and easily? Can you trace the logic of investigation consistently from the opening paragraphs to
the conclusion?
Then go back to the opening paragraphs of the article. Are the research questions specifically
stated? Is it clear what the authors want to find out? Do they make the case that this is an
important area for research inquiry?
The next section is usually a review of the existing research literature on this topic. Do the
authors present a convincing line of argument here--or does it appear that they are just namedropping (citing sources that may be important, without a clear underlying logic for how they
may be important)? Do the authors focus on ideas, or merely on discrete facts or findings?
Have they given sufficient attention to theory--the cumulative attempts at prior explanations
for the questions they are investigating? Are the research questions or hypotheses clearly
derivative of the theory and the literature review? In short: How well do the authors set the
stage for the research problem they are reporting?
The methods and procedures section is usually next; and this is where neophyte reviewers
often start (unwisely) to sharpen their knives. The selection of methods by which the
researchers collect data always involve compromises, and there are few studies that cannot be
criticized for errors of commission or omission in terms of textbook criteria for research design
and data collection procedures. You could focus on three questions here:
1. Do the authors clearly describe their research strategies? Do they present sufficient
detail about the sample from which they have collected data; the operationalization of
measures they have attempted to employ; and the adequacy of these measures in
terms of external and internal validity? In addition, there should be no surprises here:
The measures should be clearly matched to the research questions or the hypotheses.
2. Are their choices of methods adequate to find out what they want to find out in this
143
study? Would other methods provide a substantial improvement; if so, would
employing these methods be feasible or practical?
3. Do they provide some justification for the methods they have chosen? Does this appear
to be adequate?
The section presenting research results is surely the heart of the article--though not its soul
(which the reader should find in the opening paragraphs and in the discussion section).
Reviewers might consider four questions here:
1. Does the results section tell a story--taking the reader from the research questions
posed earlier to their answers in the data? Is the logic clear?
2. Are the tables and figures clear and succinct? Can they be "read" easily for major
findings by themselves, or should there be additional information provided? Are the
authors' tables consistent with the format of currently accepted norms regarding data
presentation?
3. Do the authors present too many tables or figures in the form of undigested findings?
Are all of them necessary in order to tell the story of this research inquiry; or can some
be combined? Remember that tables and figures are very expensive (from the
standpoint of the journal) and that undigested data obscure rather than advance the
cumulative development of knowledge in a field.
4. Are the results presented both statistically and substantively meaningful? Have the
authors stayed within the bounds of the results their data will support?
The discussion section is where the authors can give flight to their findings, so that they soar
into the heights of cumulative knowledge development about this topic--or crash into the
depths of their CV's, with few other scholars ever citing their findings. Of course few research
reports will ever be cited as cornerstones to the development of knowledge about any topic;
but your review should encourage authors to aspire to these heights. Consider the following as
you evaluate their discussion section:
1. Do the authors present here a concise and accurate summary of their major findings?
Does their interpretation fairly represent the data as presented earlier in the article?
2. Do they attempt to integrate these findings in the context of a broader scholarly debate
about these issues? Specifically: Do they integrate their findings with the research
literature they presented earlier in their article--do they bring the findings back to the
previous literature reviewed?
3. Have they gone beyond presenting facts--data--and made an effort to present
explanations--understanding? Have they responded to the conceptual or theoretical
problems that were raised in the introduction? This is how theory is developed.
4. Do the authors thoughtfully address the limitations of their study?
The writing style is important. Consider the three guidelines for successful communication--to
be clear, concise, and correct---and whether the authors have achieved it:
1. Is the writing clear? Do the authors communicate their ideas using direct,
straightforward, and unambiguous words and phrases? Have they avoided jargon
(statistical or conceptual) that would interfere with the communication of their
144
procedures or ideas?
2. Is the writing concise? Are too many words or paragraphs or sections used to present
what could be communicated more simply?
3. Is the writing correct? Too may promising scientists have only a rudimentary grasp of
grammar and punctuation that result in meandering commas, clauses in complex
sentences that are struggling to find their verbs, and adjectives or even nouns that
remain quite ambiguous about their antecedents in the sentence. These are not merely
technical issues of grammar to be somehow dealt with by a copy-editor down the line.
Rather they involve the successful communication of a set of ideas to an audience; and
this is the basis of scholarship today.
Your evaluation to the editor: Should this paper be (a) rejected for this journal? (b) or does it
show sufficient promise for revision, in ways that you have clearly demonstrated in your
review, to encourage the authors to invest weeks and months in revision for this journal?
Your bottom-line advice to the editor is crucial. Make a decision; state it clearly (in your
confidential remarks to the editor on the page provided).
Remember that only a few of the articles submitted to a journal will result in publication. Rates
vary from 5% to 25% of initial submissions.
Some reasons to reject a manuscript:
(a) The research questions have already been addressed in prior studies;
(b) The data have been collected in such a way as to preclude useful investigation;
(c) The manuscript is not ready for publication--incomplete, improper format, or error-ridden.
Most rejected articles do find a home in other journals. Don't tease authors with hopes for
publication in this Journal if you feel it is not likely.
Good Reviews and Bad Reviews
A good review is supportive, constructive, thoughtful, and fair. It identifies both strengths and
weaknesses, and offers concrete suggestions for improvements. It acknowledges the reviewer's
biases where appropriate, and justifies the reviewer's conclusions.
A bad review is superficial, nasty, petty, self-serving, or arrogant. It indulges the reviewer's
biases with no justification. It focuses exclusively on weaknesses and offers no specific
suggestions for improvement.
Source: How to Review a Journal Article:
Suggestions for First-Time Reviewers and Reminders for Seasoned Experts
By Vern L. Bengtson, University of Southern California,
and Shelley M. MacDermid, Purdue
Universityhttp://www.ncfr.org/journals/marriage_family/guidelines.asp
145
Criteria for manuscript review
TABLE
1
1. Scientific
quality
of the work
_ Are the methods appropriate and presented in sufficient detail to allow the results to be repeated?
_ Are the data adequate to support the conclusions?
2. Presentations
_ Writing: Is it clear, concise, and in good English?
_ Title: Is it specific and does it reflect the content of the manuscript?
_ Abstract: Is it brief and does it indicate the purpose of the work, what was done, what was found, and the significance?
_ Figures: Are they justified? Are they sharp, with lettering proportionate to the size of the figure? Are there legends to explain the figures?
_ Tables: Can they be simplified or condensed? Should any be omitted?
_ Trade names, abbreviations, symbols: Are these misused?
3. Research violations
_ Are there violations of the Guiding Principles in the Care and Use of Laboratory Animals?
_ If the research involved human subjects, were the studies performed in accordance with the Declaration of Helsinki?
If you have concerns about the welfare of animal or human subjects used by the authors, include written comments to the editor.
4. Rating
_ Assign a rating on the reviewer form; rank the manuscript relative to other work in the same field.
5. Confidential comments
_ Provide comments regarding the novelty and significance of the manuscript.
_ Provide a recommendation about the manuscript’s suitability for publication in the journal; these comments will not be returned to
the author(s).
6. Comments for authors
_ On the reviewer form, provide specific comments, preferably numbered, on the design, presentation of data, results, and discussion.
DO NOT include recommendations for publication on the second page.
_ Please be certain that your comments to the author(s) are consistent with your rating recommendation.
7. Privileged document
_ This manuscript is a privileged communication; the data and findings are the exclusive property of the author(s) and should not be
disclosed to others who might use this information in their research.
_ The manuscript, illustrations, and tables should be destroyed upon completing the review or, if anticipating a revision, kept
confidential until the review process is complete.
_ If you have shared responsibility for the review of this manuscript with a colleague, please provide that person’s name and
institutional affiliation.
WRITE A BASIC ARTICLE REVIEW
PREPARATION
Look at the questions below. You'll answer these in the Impressions Table in Step 4. Keep them in mind as
you read articles and you will increase the number of reviews your write:
1.
2.
3.
4.
5.
6.
7.
8.
Was the article clearly written?
Was the argument/message easily understood?
Was it an interesting read?
How did the spelling and grammar mistakes affect the read?
What was their readability speed or flow characteristic?
Did the author successfully introduce some sharp, witty or clever bits?
How accurate was the content?
How useful was this content to you?
Of course, these questions pre-suppose some expertise, but the standard is not so tall that well meaning
readers should avoid doing reviews. Many of us are innately equipped to spot poor grammar, spelling and
punctuation; to detect jerky flow and difficult-to-understand expressions; to recognize wit or the author's
skill with metaphors and similes, both of which add interest and insight to the writing. We may be less
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skilled to detect inaccuracies, yet the last question, usefulness, often overcomes this insofar as a fair review
is concerned.
STEP-BY-STEP INSTRUCTIONS
These instructions begin with the creation of a document that will house your review as you build it. Any
capable word processor is suitable (there's a free word processor at Google Docs with the further benefit of
on line storage and access). The instructions presuppose that you have an interest in the article's topic, your
motivation for reviewing it.
1. Step One - Open a Review Document
Open a new document and position its window to capture your keystrokes. Save the empty document with
an appropriate name, like Review-PricingTips.
Scan the chosen article and author's profile to identify and enter the following in your review window;



The title (i.e. Pricing Tips)
The author's stated role (i.e. Small Business Coach) if available
The author's published or username for this article (i.e. Peter Baskerville)
2. Step Two - 1st Read "Absorbed"
You may have already done Step Two and now wish to review the article because it's worth it. On the other
hand, you've not yet read the article. However, you suspect the article is going to be good and you read it
for the first time as the interested and absorbed reader that you are. The impressions you gain on the 1st
read will help you complete the table we offer in Step 4. Read now to enjoy and to learn because you are
interested in the topic and want to benefit from this author's work on the subject.
3. Step Three - 2nd Read "Detached"
The 2nd read will be approached in a different manner. You'll remain "detached," continually asking questions of the author as an
arms-length observer. The eight primary questions are listed above, under Preparation. Reading "detached" is not always easy
because a skillful writer continually draws you in. Resist! If you do it often enough, you'll soon figure out how to switch from
"absorbed" reader for enjoyment purposes to "detached" reader for review purposes. In fact, with time you may become capable of
simultaneous absorbed and detached reading, which is the standard for newspaper and movie critics who only get one pass.
4. Step Four - Theme and Impressions
Based on your 1st and 2nd readings, write in your document a single sentence that describes the author's
central theme, argument or message. Then look at the Impressions Table below. For each row determine
the word/phrase that you feel best answers the question. Take note of the Question Number (A to H) with
the corresponding answer grade (1 to 4).
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IMPRESSIONS TABLE
Excellent
Great
Good
Average
1
2
3
4
(A) Was it clearly
written and easily
understood?
Crystal Clear
Easily Understood
Orderly
Sufficient
(B) Was it an
interesting read?
Invigorating
Absorbing
Interesting
Satisfying
Undetectable
Only one
Evident but OK
Should be
corrected
Graceful
Polished
Smooth
Acceptable
(E) Was it sharp,
witty or clever?
Effervescent
Delightful
Pleasant
Adequate
(F) How accurate
was the content?
Without fault
General
Agreement
No issue
Some Questions
(C) How did the spelling
and grammar mistakes
affect the read?
(D) What was its
readability speed or
flow?
(G) How useful was the
content to you?
(H) OVERALL
Totally Relevant
Highly
Recommend
Useful for many Some useful points
Meritorious
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Worthwhile
One thing of
value
Acceptable
5. Step Five - Copy & Paste
Copy & paste the complete standard phrases (those between the red cut marks) list below into your
document. Using your question and answer notes, delete the question headers as well as the three answers
responses that you did not select.
--------------------------- --------------------------------
(A) UNDERSTOOD
1 - EXCELLENT – The author’s line of reasoning was crystal clear
2 - GREAT – The author’s position and argument was easily understood
3 - GOOD – The author presented an orderly explanation of the concepts
4 - AVERAGE – The author presented sufficient information to understand the concepts
(B) INTERESTING
1 - EXCELLENT – and it was an invigorating read.
2 - GREAT – and it was an absorbing read.
3 - GOOD – and it was a interesting read.
4 - AVERAGE – and it was a satisfying read.
(C) SPELLING AND GRAMMAR
1 - EXCELLENT – Moreover, if there were any spelling or grammar mistakes they were undetectable to me.
2 - GREAT – Moreover, it was well constructed and presented apart from one [spelling/grammar] mistake.
3 - GOOD – Moreover, while there were some [spelling/grammar] mistakes they did not detract significantly
from the reading experience.
4 - AVERAGE –. However, I believe that the spelling and grammar should be corrected.
(D) SPEED
1 - EXCELLENT – [Author's surname]’s engaged a graceful writing style
2 - GREAT – [Author's surname]’s engaged a polished writing style
3 - GOOD – [Author's surname] engaged a smooth writing style
4 - AVERAGE – [Author's surname]'s writing style was acceptable
(E) CLEVER
1 - EXCELLENT – with the [sharp/clever/witty/graphical] inclusions bringing a real effervescence to the
reading experience.
2 - GREAT - with the [sharp/clever/witty/graphical] inclusions making for a delightful reading experience.
3 - GOOD – with the [sharp/clever/witty/graphical] inclusions adding significantly to the reader interest.
4 - AVERAGE - with the [sharp/clever/witty/graphical] inclusions being satisfactorily handled.
(F) ACCURATE
1 - EXCELLENT – I am [very, reasonably, quite] knowledgeable about this subject and believe that the
content was without fault.
2 - GREAT – I am [very, reasonably, quite] knowledgeable about this subject and I am in general agreement
with all the Author’s stated positions.
3 - GOOD – I am [very, reasonably, quite] knowledgeable about this subject and find no issue with the
content.
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4 - AVERAGE – I am [very, reasonably, quite] knowledgeable about this subject and some question remain
concerning some of the Author’s statements.
(G) USEFUL
1 - EXCELLENT – [and/but] it was totally relevant and applicable to me.
2 - GREAT – [and/but] I believe that it would be very useful for many that are interested in this topic.
3 - GOOD – [and/but] the author made some good points that others might find useful.
4 - AVERAGE – [and/but] the author makes a good point about [.............].
(H) OVERALL
1 - EXCELLENT – Overall, I rate this article as a brilliant read that I would highly recommend to my friends.
2 - GREAT - Overall, I would rate this article as a great read of high merit.
3 - GOOD – Overall, I would rate this article as a good and worthwhile read.
4 - AVERAGE – Overall, I would rate this article as an acceptable read.
---------------------- ---------------------------
6. Step Five - Compile: Complete/Remove/Make/Link/Adjust
Now turn the individual components of an article review into a complete paragraph by doing the following:





Complete the opening sentence "This article titled '[Article Title], written by the [Author's stated role]
[Author's published name or username], sets out to show [Central theme, argument or message]
Remove the NUMBER and GRADE from the front of the 'standard phrase'
Make the applicable choice in the [square brackets] when asked
Link the 'standard phrases together to form sentences and then complete the paragraph
Adjust the grammar and phrasing to suit your style of expression (if required)
7. Final Step - Place and Publish
Source: http://knol.google.com/k/peter-baskerville/how-to-quickly-write-a-basic-article/14j3i4hyjvi88/27#
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HANDOUT -7
COMMUNITY


A community can be thought of in relation to common interests, in which groups share certain goals,
objectives, roles, priorities or views in common.
This might be based on common geographic location, or social, cultural or religious affiliations.
Types of Communities
Communities can be classified as:
 ƒ Geographic (an urban mass; scattered rural dwellings; temporary homes built alongside railroad
tracks.)
 ƒ Religious/ethnic/political
 ƒ Socio-economic (caste/class)
ACTIVITY – 1
Understanding the community
To do this you must:
 Identify opinion leaders and have informal discussions with them and with street children.
 Get to know the profile of the community to identify any special features which will influence their
involvement.
 Find out how they feel about the activities you want to introduce.
 Find out if they agree with the proposals.
 Determine any conflicting interests.
Objective of the activity:
By the end of this session, participants will be able to Understanding the community.
Exercise is taken from a WHO module in which the investigator wants to Work With Street Children
regarding substance Use, Sexual and Reproductive Health including HIV/AIDS and STDs.
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Learning Activity
Understanding the community.
The lemon game.
With the help of a facilitator or trainer:
 Obtain lemons or any available fruits and put them in a basket.
 Each participant must pick a lemon from the basket and look at it very briefly (first picking).
 Each participant must then put the lemon back into the basket.
 Each participant must try to pick their lemon from the basket and look at it a little longer than the
first time (second picking).
 Each participant should put the lemon back into the basket.
 Each participant must pick his/her lemon from the basket (third picking).
 By the ‘third picking’ each participant must be able to identify his/her lemon.
The facilitator will then ask those who were not able to identify their lemons to explain why they
failed to do so. Afterwards, the facilitator will ask those who identified their lemons to explain
why it was easier for them to pick out their lemon.
The facilitator or trainer will conclude with an explanation which is offered in the trainer tips
regarding the learning points of this game.
To understand the community you must exercise patience and get to know the
community well by making several contacts.
Field visit.
Conduct an informal visit to a potential community that you might work with such as shop
Owners, government officials and street children. Ask them the following questions:




Have children lived or worked on the streets during other times in the history of your
community?
At what age does the community believe that children should begin earning? At what age
are they expected to live away from their parents? Is the age different for girls and boys?
What are the major religions in the community? What are their beliefs about children,
poverty, suffering, and helping others?
What religious beliefs do street children in your community hold? Do they participate in
religious ceremonies, rituals or festivals?
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







What does the community think about substance use? How many adults use substances of
some kind?
What does the community think about sexual and reproductive health and HIV/AIDS/STDs
among street children? Do they think street children should be helped?
What activities do members of the community think are appropriate for boys and girls? Do
people in the community feel differently towards street girls and street boys?
What are the major ethnic groups in the community? What are their views on working
children, on families, on substances, and reproductive health?
How does the community view people who work with street children?
How does the local government view street children and those who work with them? Do
government officials feel any responsibility to become involved with street children?
Are there laws that prevent children from living or working on the streets? Are there laws
that prevent or restrict street educators from working with street children?
Are there international development agencies in your area? How does the community view
these agencies?
Use this information as a basis to approach and work with the community in order to avoid a
conflict of interest.
Source:
Page 4-5 department of mental health and substance dependence Geneva, Switzerland working with street children module
9involving the community a training package on substance use, sexual and reproductive health including HIV/aids and stds
world health organization mental health determinants and populations department of mental health and substance
dependence Geneva, Switzerland
153