Chapter 2
Health Determinants, Measurements, and
Trends
Richard Skolnik
The Importance of Measuring Health
Status
In order to address global health issues, we
must understand:
• The factors that most influence health status
• The indicators used to measure health status
• The trends that have occurred historically
Figure 2.1: Key Determinants of Health
Data from: The Public Health Agency of Canada. What Determines Health.
Available at: http://www.phac-aspc.gc.ca/ph-sp/determinants/indexeng.php#determinants. Accessed November 19, 2010.
Key Health Status Indicators
Health status indicators are useful for:
• Finding which diseases people suffer from
• Determining the extent to which the disease
causes death or disability
• Practicing disease prevention/interventions
To perform these functions, it is important to
use a consistent set of indicators and have
accurate data
Key is a Vital Registration System
• Vital registration systems record births,
deaths, and causes of death
• An accurate system is key to having quality
data on a population
• Many low- and middle-income countries lack a
vital registration system
• Developing a system is progress towards
understanding and addressing health
problems
Key Health Status Indicators
• Neonatal mortality rate
– # deaths of infants under 28 days of age per
1000 births in a year
Figure 2.4: Neonatal Mortality Rate, by WHO Region, 2004
Trends in neonatal mortality – more recent data
Data from World Health Organization. Neonatal and Perinatal Mortality:
Country, Regional, and Global Estimates 2004. Geneva: WHO; 2007: Table 2.
Neonatal Mortality
• One quarter to one half of all deaths occur
within the first 24 hours of life
• 75% of deaths occur in the first week
• The 48 hours immediately following birth is the
most crucial period for newborn survival
• A baby's chance of survival increases
significantly with the presence of a skilled birth
attendant at the birth
WHO
Neonatal (<28 days) Mortality Data
Population
Neonatal mortality rate,
Year
deaths/1000 live births
U.S. overall
4.19
2009
Maine
4.2
2006
Black infants
8.2
2009
White infants
3.43
2009
Key Health Status Indicators
• Infant mortality rate
– # deaths of infants in the first year of life
per 1000 births in a year
Figure 2.3: Infant Mortality Rate, by World Bank Region, 2008
Data from The World Bank. World Development Indicators, Data Query.
Available at: http://databank.worldbank.org. Accessed June 29, 2010.
Infant (<1 yr) Mortality Data
Population
Infant mortality rate,
Year
deaths/1000 live births
U.S. overall
Black
6.8
5.7
6.7
6.42
12.71
2001
2004
2008
2009
2009
Key Health Status Indicators
• Under 5 mortality rate
– aka child mortality rate
– the probability that a newborn infant will
die before reaching the age of 5, # per 1000
live births
Figure 2.5: Under-five Child Mortality Rate, by World Bank Region, 2008
Data from The World Bank. World Development Indicators, Data Query.
Available at: http://databank.worldbank.org. Accessed June 29, 2010.
Under 5 Mortality - WHO
• 6.9 million children under the age of five died
in 2011.
• More than half of these early child deaths are
due to conditions that could be prevented or
treated with access to simple, affordable
interventions.
Under 5 Mortality - WHO
• Leading causes of death:
– pneumonia, preterm birth complications,
diarrhea, birth asphyxia and malaria
– ~ one third of all child deaths are linked to
malnutrition.
• Children in sub-Saharan Africa are about 16.5
times more likely to die before the age of five
than children in developed regions.
Key Health Status Indicators
• Neonatal mortality rate - # deaths of infants
under 28 days of age per 1000 births in a year
• Infant mortality rate - # deaths of infants in
the first year of life per 1000 births in a year
• Under 5 mortality rate (aka Child mortality
rate) – the probability that a newborn infant
will die before reaching the age of 5, # per
1000 live births
Key Health Status Indicators
• Maternal mortality rate
– # women who die as a result of pregnancy
or childbirth complications per 100,000 live
births in a year
Figure 2.6: Maternal Mortality Ratio, by World Bank Region, 2005
Data from The World Bank. World Development Indicators, Data Query. Available at:
http://databank.worldbank.org. Accessed June 29, 2010..
Worldwide Data – Maternal Mortality
• 87% deaths in Sub-Saharan Africa and South
Asia
• 50 percent of all deaths occurred in six
nations: India, Nigeria, Pakistan, Afghanistan,
Ethiopia, and the Democratic Republic of
Congo
Key Health Status Indicators
• Life expectancy at birth
– average # of years a newborn could expect
to live if current mortality rates were to
continue for the rest of the infant’s life
Figure 2.2: Life Expectancy at Birth, by World Bank Region, 2008
Data from the World Bank. World Development Indicators, Data Query.
Available at: http://databank.worldbank.org. Accessed June 29, 2010.
Historical Trends based on Health Status Indicators
Table 2.11: Life Expectancy and Percentage Gain in Life Expectancy, 1960-2008, by
World Bank Region
Data from the World Bank. World Development Indicators, Data Query.
Available at: http://databank.worldbank.org. Accessed July 6, 2010.
Worst country for women & children –
Afghanistan
• 14% of births are attended by a health
professional
• Lifetime risk of woman dying as a result of
pregnancy or childbirth: 1 in 11
• Life expectancy girl born today = 45
Afghanistan
• Under 5 mortality rate: 1 in 5 children die
before the age of 5
• Every woman is likely to suffer the loss of a
child in her lifetime
• 39% of children moderately or severely
underweight
• 52% Do not have access to clean water
Key Terms
• Morbidity – sickness/illness
– physiological and/or psychological
• Mortality – death
– Mortality/Death rate expressed as # deaths per
1000 in a population in a year
• Disability – “temporary or long-term
reduction in a person’s capacity to function”
Key Terms
• Prevalence - # of people suffering from a
particular health condition over a period of
time
– Generally consider at a given point in time (crosssectional) – point prevalence
– Measure of existing cases at a given time
• Incidence rate - # of people contracting a
disease per 1000 at risk in a year
– Measure of new cases per year
Classification of Diseases
• Communicable diseases – spread by an
infectious agent
– Influenza, HIV/AIDS, measles, malaria, cholera
• Non-communicable diseases – diseases not
spread by an infectious agent
– Hypertension, diabetes, lung cancer, CVD
• Injuries
– Accidents, violence, burns, cuts
Figure 2.10: The Burden of Disease by Group of Cause, Percent of Deaths, 2001
Data from Lopez AD, et al Global Burden of Disease and Risk Factors.
Washington, DC and New York: The World Bank and Oxford University Press;
2006:8.
Table 2.10: The "Demographic Divide:" The Example of Nigeria and Japan
Data from PRB. 2009 World Population Data Sheet. Available at
http://www.prb.org/Publications/Datasheets/2009/2009wpds.aspx. Accessed November 24,
2010.
The Global Burden of Disease
Causes of Death by Region
• Higher income countries tend to have a
greater burden of non-communicable disease
• Lower income countries to have a greater
burden of communicable disease
Low and Middle Income
Countries
% Deaths
Rank. Cause of death, % of deaths
54 % Non-Communicable Diseases
1. Heart disease 11.8%
2. Strokes 9.5%
5. Perinatal conditions 5.1%
6. COPD 4.9%
36 % Communicable Diseases
3.
4.
7.
8.
9.
10 % Injuries
10. road accidents 2.2%
respiratory infections 7.0%
HIV/AIDS 5.3%
Diarrheal disease 3.7%
TB 3.3%
Malaria 2.5%
High Income Countries
% Deaths
Rank. Cause of death, % of deaths
87 % Non-Communicable Diseases
1. Heart disease 17.3%
2. Strokes 9.9%
3. Trachea, lung cancers 5.8%
5. COPD 3.8%
6. Colon and rectal cancers 3.3%
7. Alzheimer’s/dementia 2.6%
8. Diabetes 2.6%
9. Breast cancer 2.0%
10. Stomach cancer 1.9%
5.7 % Communicable Diseases
4. Respiratory infections 4.4%
7.5 % Injuries
The Global Burden of Disease
Causes of Death by Age
• Children in low- and middle-income countries
often die of communicable disease
• HIV/AIDS and TB are among the leading causes
of death among adults in low and middleincome countries
Table 2.5: The 10 Leading Causes of Death in Children
Ages 0-14, by Broad Income Group, 2001
Table 2.6: The 10 Leading Causes of Death in
Adults 15-59, by Broad Income Group, 2001
The Global Burden of Disease
In most low- and middle-income countries:
• Rural people will be less healthy
• Disadvantaged ethnic minorities will be less
healthy
• Women will suffer as a result of their social
positions
• Poor people will be less healthy
• Uneducated people will be less healthy
Measuring the Burden of Disease
• Two indicators used to compare how far
countries are from a state of good health
• Health-Adjusted Life Expectancy (HALE)summarizes expected number of years to be
lived in what might be termed the equivalent
of good health
• Disability-Adjusted Life Year (DALY)- a unit
for measuring the amount of health lost
because of a particular disease or injury
Measuring the Burden of Disease
• HALE – Health-Adjusted Life Expectancy
– Calculated by a standard methodology by World
Health Organization (WHO)
– Years of ill health are weighted according to
severity and subtracted from overall lifeexpectancy
Table 2.2: Life Expectancy at Birth and Health-Adjusted Life Expectancy,, 2004
Data from WHO. Core Health Indicators. Available at: http://www3.who.int/whosis/core/core_select_process.cfm.
Accessed: September 24, 2006.
DALY – Disability Adjusted Life Year
– First measured by World Bank as a “health gap
measure”
• Used by World Bank and WHO – controversial measure
– DALYs are thought to be a better indicator of the
health of a population than mortality rates
– DALY takes into account that many conditions
associated with poor health are not fatal
– A higher DALY value indicates a greater health
burden
DALYs
• “This time-based measure combines years of
life lost due to premature mortality and years
of life lost due to time lived in states of less
than full health.
• The DALY metric was developed in the original
Global Burden of Disease 1990 study to assess
the burden of disease consistently across
diseases, risk factors and regions.”
DALYs
• A DALY is a measure of years of fully healthy life lost
due to disease, death, …….disability…..
– The higher the DALY value the more years lost due
this “condition” – or the more years living with
compromised health
DALYs
• DALYs are intended to provide a comparable
measure of the burden of disease
• Used to:
– Aid in setting health care priorities
• Treatment and prevention
– Aid in setting research priorities
– Identify high need populations and target health
interventions
– Measure success/effectiveness of interventions
DALYs…put another way
• Measures how many healthy years of life are lost
between the population being studied and the
healthiest possible populations
– Consider
•
•
•
•
•
Communicable diseases
Maternal, perinatal (1st weeks after birth)
Nutritional disorders
Non-communicable disorders
Injuries/accidents
Grouped
together
Table 2.3: The 10 Leading DALYs
Low and Middle-Income
High-Income Countries
Table 2-4 on page 30 shows DALYs in low and middle-income countries by regions
Calculating DALYs
• Disabilities/health conditions are weighted by
one of 6 values based on the limitations or
reduction in years of life associated with the
“condition”
• The more serious the “condition” the higher
the weighting
– Deaf, weighting = .33
– Dead, weighting = 1 (most serious!)
• Calculating DALYs
WEIGHTING of DISABILITIES
• Weightings quantify societal preferences for
health states in relation to the societal ideal of
good health.
• On average, society judges a year with
blindness (weight 0.43) to be preferable to a
year with paraplegia (weight 0.57), and a year
with paraplegia to be preferable to a year with
unremitting unipolar major depression
(weight 0.76).
•
Source this slide and next
http://www.who.int/quantifying_ehimpacts/publications/en/9241546204chap3.pdf
WEIGHTING of DISABILITIES
• On average, society would prefer a person to
have a year in good health followed by death,
than a year with paraplegia followed by death.
• Society would prefer a person to live three
years with paraplegia followed by death (3
years x 0.57 = 1.7 lost “healthy” years), than
have one year of good health followed by
death (2 lost years of good health).
Calculation of DALYs
(without age-weighting and discounting)
• The calculation of DALYs of a woman who has been
deaf since she was 5 and dies when she is 50:
(deafness is set at 0.33; life expectancy 80) :
• Number of healthy life years × the disability
weight of full health (0) + life years with disability
(50) × disability weight for deafness (0.33) + life
years lost (30) × the weighting of death (1)
• (5 × 0)+ (45 × 0.33) + (30 × 1) = 47.35 DALYs
Other choices behind DALY
• In addition to adjusting the value of life
years with disability weights, and choosing a
particular life expectancy, the value of a life
year is modified by
• Age weighting
– life years of children and old people are
counted less
• Discounting
– the value of a life year now is set higher than
the value of future life years
Age-weights
Calculating DALY score,
with age weighting and discounting.
• Girl, 5 years old, with below-knee
amputation who lives until she is 82.5:
• DALYs= life years lived with disease
(77.5) × disability weight (0.3) × ageweight (a1)× discounting factor
(3%/year)
• 77.5 × 0.3 × a1 × d2 = 10.5 DALYs
The Young
• The 5-year-old girl in the prior example
yielded 10.5 DALYs.
• However, the DALY score without age-weight
and discounting would be
• 77.5 × 0.3 = 23.3 DALYs
• This result is twice as high, and would give
her a higher priority.
DALYs - Justice Issues?
• The DALY approach has been
criticised for discriminating
– the young
– the elderly
– the disabled
– women
Finding Health Statistics
• WHO – WHO Health Statistics and Health Information
Systems website is a rich source of data
• Data is available by country and by region of the world
• Could spend the entire semester just mining this data!
• World Bank
• Gapminder – World Data
• MDG related data
– Gapminder MDG data
Figure 2.11: Gross Domestic Product Per Capita and Female Life Expectancy at Birth,
Selected Countries, 2004
Data from WHO. Core Health Indicators. Available at:
http://www3.who.int/whosis/core/core_select_process.cfm. Accessed:
September 24, 2006.
Hans Rosling
• Hans Rosling on Health Statistics and Child
Mortality
– http://www.gapminder.org/videos/reducing-childmortality-a-moral-and-environmental-imperative/
Figure 2.9: The Demographic Transition: (A) High Fertility/High Mortality, (B) Declining
Mortality/High Fertility, (C) Reduced Fertility/Reduced Mortality
Reprinted from U.S. Census Bureau, International Population Reports WP/02,
Global Population Profile: 2002. Washington, DC: U.S. Government Printing
Office; 2004, p. 35.
Figure 2.7: Percentage of Children 0 -5 Whose Births Have been Registered, by Income
Quintile
Data from UNICEF. Progress for Children: Achieving the MDGs with Equity. Available at:
http://www.unicef.org/media/files/Progress_for_Children-No.9_EN_081710.pdf.
Accessed September 17, 2010. .
Figure 2.8: World Population - 1950 to 2050
Adapted from: Haub, Carl and PRB. Data from United Nations Population Division. World
Population Prospects, The 2008 Revision. Available at: http://esa.un.org/UNPP/. Accessed
December 4, 2010.
Table 2.1: Key Health Status Indicators
Adapted from: Haupt A, Kane TT. Population Handbook. Washington, DC:
Population Reference Bureau; 2004; World Bank. Beyond Economic Growth
Student Book: Glossary.
http://www.worldbank.org/depweb/english/beyond/global/glossary.html.
Accessed April 15, 2007.
Table 2.3: The 10 Leading Causes of Death and DALYs 2001
Adapted with permission from Lopez AD, Mathers CD, Murray CJL. The Burden
of Disease and Mortality by Condition: Data, Methods, and Results for 2001. In:
Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL, eds. Global burden of
disease and risk factors. Washington, DC and New York: The World Bank and
Oxford University Press; 2006.
Table 2.4: The Ten Leading Causes of the Burden of Disease in Low- and Middleincome Countries, by Region, 2001
Reprinted with permission from Lopez AD, Mathers CD, Murray CJL. The Burden of Disease
and Mortality by Condition: Data, Methods, and Results for 2001. In: Lopez AD, Mathers CD,
Ezzati M, Jamison DT, Murray CJL, eds. Global Burden of Disease and Risk Factors. New York:
Oxford University Press 2006:91. Washington, DC and New York: The World Bank and
Oxford University Press
Table 2.5: The Ten Leading Causes of Death in Children Ages 0-14, by Broad Income
Group, 2001
Adapted with permission from: Lopez A, Begg S, Bos E. Demographic and
Epidemiological Characteristics of Major Regions, 1990-2001. In: Lopez A,
Mathers C, Ezzati M, Jamison D, Murray C, eds. Global Burden of Disease and
Risk Factors. Washington, DC and New York: The World Bank and Oxford
University Press; 2006:70.
Table 2.6: The Ten Leading Causes of Death in Adults 15-59, by Broad Income Group,
2001
Adapted with permission from: Lopez A, Begg S, Bos E. Demographic and
Epidemiological Characteristics of Major Regions, 1990-2001. In: Lopez A,
Mathers C, Ezzati M, Jamison D, Murray C, eds. Global Burden of Disease and
Risk Factors. Washington, DC and New York: The World Bank and Oxford
University Press; 2006:70.
Table 2.7: The Ten Leading Causes of Death by Sex, in Low- and Middle-Income
Countries, 2001
Data from Lopez A, Begg S, Bos E. Demographic and Epidemiological
Characteristics of Major Regions, 1990-2001. In: Lopez A, Mathers C, Ezzati M,
Jamison D, Murray C, eds. Global Burden of Disease and Risk Factors.
Washington, DC and New York: The World Bank and Oxford University Press;
2006:70.
Table 2.9: Percentage of the Population Projected to be Over 65 Years of Age
Based on Haub, Carl and PRB. Data from United Nations Population Division. World Population
Prospects, The 2008 Revision. Available at: http://esa.un.org/UNPP/. Accessed December 4, 2010.
Table 2.12 (cont.): Trends in the Ten Leading Causes of the Burden of Disease, by
Income Group, 2004 - 2031 continued
Data from World Health Organization. Global Burden of Disease (GBD). Available at:
http://www.who.int/healthinfo/global_burden_disease/en/. Accessed September 14, 2010.