1
Think about…
25.1 Non-infectious diseases
25.2 Prevention of diseases
Recall ‘Think about…’
Summary concept map
2
Cancer is the leading cause of death.
malignant tumour in air sac
3
There has been an increase of over 25%
in the number of deaths from cancer
during the past 10 years.
4
25.1 Non-infectious diseases
• cannot be transmitted from person
to person
• account for about 60% of deaths
and disabilities
• many develop slowly
 chronic diseases (慢性病)
• associate with risk factors (高危因素)
5
Risk factors
A risk factor (高危因素) is
anything that may increase the
risk of developing a disease.
There are four types of risk
factors:
6
25.1 Non-infectious diseases
1 Biological risk factors
e.g. age, sex, race
• nasopharyngeal cancer (鼻咽癌) is
more common in Chinese
7
25.1 Non-infectious diseases
2 Genetic risk factors
e.g. family history
• people with family history of diabetes
mellitus have a higher risk of the disease
8
25.1 Non-infectious diseases
3 Environmental risk factors
e.g. sunlight, air pollution, radiation
• long exposure to sunlight increases
the risk of skin cancer
9
25.1 Non-infectious diseases
4 Behavioural risk factors
e.g. smoking, insufficient exercise
• smokers have a higher risk of
lung cancer
10
25.1 Non-infectious diseases
Allergies
• an overreaction of the immune
system to foreign substances
allergens (過敏原)
e.g.
dust mites (塵蟎)
pollen
11
25.1 Non-infectious diseases
Allergies
• an overreaction of the immune
system to foreign substances
allergens (過敏原)
e.g.
animal hair
insect stings
12
25.1 Non-infectious diseases
Allergies
• an overreaction of the immune
system to foreign substances
allergens (過敏原)
e.g.
eggs & peanuts
medicines
13
25.1 Non-infectious diseases
Allergies
• mild symptoms: running
nose, sneezing, ithciness
or a skin rash (疹)
14
25.1 Non-infectious diseases
Allergies
• severe symptoms: swelling of lips,
tongue or throat, shortness of breath
or loss of consciousness
• often inherited (遺傳)
15
25.1 Non-infectious diseases
Allergies
Prevention
• avoid the allergen
1 People with food allergy should read
carefully any label and warning on prepacked food
16
25.1 Non-infectious diseases
Allergies
Prevention
• avoid the allergen
2 People with asthma
(哮喘) should avoid
contact with dust mites
17
Cancer
18
Cancers of the human body
19
Major causes of cancer deaths
Males
Females
1 Lung cancer
1 Lung cancer
2 Liver cancer
2 Colon cancer &
rectal cancer
20
Major causes of cancer deaths
Males
Females
3 Colon cancer &
3 Breast cancer
rectal cancer
4 Stomach cancer
4 Liver cancer
21
Major causes of cancer deaths
Males
Females
5 Prostate cancer 5 Stomach cancer
(前列線癌)
22
1
What is cancer
23
2
Why are there differences in cancer
occurrence in males and females
24
3
Can cancer be prevented
How
25
25.1 Non-infectious diseases
Cancer
changes in DNA
uncontrolled
cell division
tumour
(benign or malignant)
26
Cancer as loss of growth control
27
Benign vs Malignant tumour
Benign tumour
cells growth and
spread unrestrained
Malignant tumour
--cancer
28
25.1 Non-infectious diseases
Cancer
• benign tumour (良性腫瘤):
- tumour cells
surrounded by
a fibrous capsule
- tumour cells do not
spread to other
tissues
a benign tumour
of fatty tissue
29
25.1 Non-infectious diseases
Cancer
• malignant tumour (惡性腫瘤):
- also called cancer
- tumour cells can spread through the
bloodstream and lymphatic system
- at new sites, tumour cells continue
to divide uncontrollably
 damage the tissues
30
Invasion and metatasis
Malignant
tumors are
tumors that
are capable of
spreading by
invasion
and
metastasis
31
Metatasis
a melanoma (a cancer of
pigmented cells) arising in
the skin can have cells that
enter the bloodstream and
spread to distant organs such
as the liver or brain.
Cancer cells in
the liver would
be called
metastatic
melanoma, not
liver cancer.
32
25.1 Non-infectious diseases
Cancer
1 A cell begins to divide more often
than normal.
cell with changes
in DNA
33
25.1 Non-infectious diseases
Cancer
2 One of the tumour cells has further
tendency to divide.
tumour (腫瘤)
cell with
further
changes
in DNA
34
25.1 Non-infectious diseases
Cancer
3 The malignant tumour develops its
own blood vessels.
cancer cells
blood
vessel
35
25.1 Non-infectious diseases
Cancer
3 The tumour cells (cancer cells) travel
through the blood to invade other tissues.
cancer cells
blood
vessel
36
Characteristic of cancer cells I
Suggest how cancer cells appear under
microscope?
37
Characteristic of cancer cells II
a large number of
dividing cells,
variation in nuclear
size and shape,
loss of specialized cell
features,
loss of normal tissue
organization,
a poorly defined tumor
boundary.
38
Diagnosis- Pap smear and biopsy
39
Colorectal Cancer Staging
Staging is the process of determining how far a tumor has spread beyond its
original location. Staging may not be related to the size of the tumor. Treatment
decisions also depend upon the stage of a tumor. Staging for colorectal cancer is as
follows:
Stage 0 – The cancer is found only in the
innermost lining of the rectum or colon.
Stage I – The cancer has not spread
beyond the inner wall of the rectum or
colon.
Stage II – The cancer has spread into the
muscle layer of the rectum or colon.
Stage III – The cancer has spread to at
least one lymph node in the area.
Stage IV – The cancer has spread to distant
sites in the body, such as the bones, liver,
or lungs. This stage is NOT dependent on
how far the tumor has penetrated or if the
cancer has spread to lymph nodes near the
tumor.
40
Screening for Colorectal Cancer
It is recommended that most people have a screening colonoscopy
every year starting at age 50. A colonoscopy allows examination of
the entire colon and rectum using a tiny camera. This test can find
cancers in the early, most treatable stage and actually prevent
cancers from developing by removing polyps, as shown here.
41
Factors that can lead to cancer
42
Clues from geographic distribution
of cancer incidents
43
Risk factors: UV, X-ray, tobacco
44
Risk factor: some viral infections
45
Risk factor_age
Because cancer
usually requires a
number of
mutations, the
chances of
developing cancer
increase as a
person gets older
because more time
has been available
for mutations to
accumulate.
46
Cancer
abnormal function
of the genes
47
25.1 Non-infectious diseases
Cancer
• agents that can induce changes in DNA
and make cells cancerous
 carcinogens (致癌物)
symbol of carcinogens
48
25.1 Non-infectious diseases
Cancer
Chemical
Carcinogen
Tar in cigarette smoke
Linked to
Lung cancer
Nitrosamine (亞硝胺)
in salted fish
Nasopharyngeal
cancer
Asbestos (石棉) in
construction materials
Throat cancer,
lung cancer
49
25.1 Non-infectious diseases
Cancer
Radiation
Carcinogen
Linked to
Ultraviolet light (紫外光) Skin cancer
in sunlight
X-ray in medical
examination
Blood cancer,
thyroid cancer
(甲狀腺癌)
50
25.1 Non-infectious diseases
Cancer
Virus
Carcinogen
Linked to
Human Papillomavirus Cervical cancer
(HPV) (人類乳頭瘤病毒) (子宮頸癌)
Hepatitis B virus
Liver cancer
51
Carcinogens _UV light causes
Thymine-dimer formation
52
Carcinogens _nitrous acid
Chemical mutagens
such as nitrous acid
(HNO2) may cause
nucleotide deamination:
conversion of an amino
group to a keto group.
Thus a transition
mutation occurs: e.g.
adenine are converted
to hypoxanthine (which
base pairs with
cytosine).
53
Chemical mutagens such as nitrous acid (HNO2) may cause nucleotide deamination:
conversion of an amino group to a keto group.
adenine are converted to hypoxanthine (which base pairs with cytosine), respectively.
54
Carcinogens _base analogues
5-Bromo-uracil can substitute for T, and then wind up binding with G (rather than A), thus
inducing a TRANSITION (G->A) mutation.
55
High energy radiation induces mutation:
High energy radiations cause
damages to DNA
Ionizing radiation causes the formation of
ions and free radicals that react with DNA;
base substitutions or breakage of the
sugar-phosphate backbone result.
Ultraviolet radiation is non-ionizing; it
causes bonding between adjacent
thymines.
DNA repair
Damage to DNA caused by ultraviolet
radiation can be repaired by enzymes
that cut out and replace the damaged
portion of DNA.
56
DNA damage vs DNA repair
57
25.1 Non-infectious diseases
Cancer
• caused by an accumulation of changes
in DNA that controls cell division
 more common in people who are
repeatedly exposed to carcinogens
or in older people
• changes in DNA can
be inherited
58
Cancer prevention
59
25.1 Non-infectious diseases
Cancer
Prevention
• reduce the exposure to carcinogens
1 Wear masks and gloves
when handling
construction materials
with asbestos
60
25.1 Non-infectious diseases
Cancer
Prevention
• reduce the exposure to carcinogens
2 Wear sun protection
to reduce exposure
to ultraviolet light
61
25.1 Non-infectious diseases
Cancer
Prevention
• reduce the exposure to carcinogens
3 Avoid early sex and
multiple sex partners to
reduce the risk of HPV
infection
HPV
62
25.1 Non-infectious diseases
Cancer
Prevention
• adopt a healthy lifestyle
1 Do not smoke
 the risk of developing
lung cancer is much lower
63
25.1 Non-infectious diseases
Cancer
annual mortality rate per
1000 men
Prevention
64
years after giving up smoking
65
25.1 Non-infectious diseases
Cancer
Prevention
• adopt a healthy lifestyle
2 Include more vegetables in the diet
- dietary fibre increases
the bulk of faeces
 speeds up the passage of
carcinogens through the
intestine
66
25.1 Non-infectious diseases
Cancer
Prevention
• adopt a healthy lifestyle
2 Include more vegetables in the diet
 the risk of developing
colon cancer is lower
67
Well-done red meat linked to aggressive
prostate cancer
68
2. What do you consider as processed
meat? (WHO)
Processed meat refers to meat that has been transformed
through salting, curing, fermentation, smoking, or other
processes to enhance flavour or improve preservation.
Examples of processed meat include hot dogs (frankfurters),
ham, sausages, corned beef, and biltong or beef jerky as well as
canned meat and meat-based preparations and sauces.
69
1. What do you consider as red meat?
Red meat refers to all mammalian muscle meat, including,
beef, veal, pork, lamb, mutton, horse, and goat. (WHO)
70
25.1 Non-infectious diseases
Cancer
mortality from colon cancer
(per 100 000 persons)
Prevention
71
daily intake of dietary fibre (g)
10. What types of cancers are linked
or associated with eating red meat?
The strongest, but still limited,
evidence for an association with
eating red meat is for colorectal
cancer. There is also evidence of
links with pancreatic cancer and
prostate cancer.
11. What types of cancers are linked
or associated with eating processed
meat?
The WHO Working Group concluded
that eating processed meat causes
colorectal cancer. An association
with stomach cancer was also seen,
but the evidence is not conclusive.
72
Avoiding carcinogens can reduce the
risk of cancer
• Lifestyle
choices can
help reduce
cancer risk
73
Carcinogens in the workplace
74
Diagnosis of
cancer_ colon
cancer by DNA
analysis
75
Diagnosis of cancer_mammogram
low dose X-ray of
the breast, which
can pick up very
small breast cancer.
76
25.1 Non-infectious diseases
Cardiovascular diseases
• involve the heart and/or the
blood vessels
e.g. coronary heart disease (冠心病),
stroke (中風), high blood pressure
77
25.1 Non-infectious diseases
Cardiovascular diseases
Coronary heart disease
• coronary arteries supply food and
oxygen to cardiac muscles continuously
3D animation
coronary
artery
78
25.1 Non-infectious diseases
Cardiovascular diseases
Coronary heart disease
smooth lining
blood flow unrestricted
79
25.1 Non-infectious diseases
Cardiovascular diseases
Coronary heart disease
blood flow slowed down
cholesterol plaque
80
25.1 Non-infectious diseases
Cardiovascular diseases
Coronary heart disease
artery blocked by a blood clot
(a heart attack results)
81
25.1 Non-infectious diseases
Cardiovascular diseases
Heart attack
• great pain in the chest
• the heart may even stop beating
 death
82
25.1 Non-infectious diseases
Cardiovascular diseases
Stroke
• blockage occurs in arteries carrying
blood to the brain
• brain cells die within minutes without
oxygen supply
 paralysis (癱瘓)
 death
83
25.1 Non-infectious diseases
Cardiovascular diseases
High blood pressure
• causes:
1 the heart pumps blood with
excessive forces
2 the arterioles are narrowed, so that
blood exerts greater forces on the walls
84
25.1 Non-infectious diseases
Cardiovascular diseases
High blood pressure
• damages the inner walls of arteries
• increases the risk of coronary heart
disease, heart attack and stroke
85
25.1 Non-infectious diseases
Cardiovascular diseases
High blood pressure
Risk factors:
• high blood cholesterol
• smoking
• aging
• family history
86
25.1 Non-infectious diseases
Cardiovascular diseases
High blood pressure
Risk factors:
• obesity
• diabetes mellitus
• stress
• insufficient exercise
• alcohol use
87
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
1 Avoid eating too much cholesterol
and lipids
egg yolk
internal
organs
seafood
88
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
1 Avoid eating too much cholesterol
and lipids
- trans fat (反式脂肪)
and certain vegetable
oils increase blood
cholesterol level
foods high in
trans fat
89
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
2 Stop smoking
- nicotine causes constriction of
blood vessels
 blood pressure rises
 the heart has to work harder
90
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
2 Stop smoking
- nicotine increases stickiness of blood
platelets and formation of blood clots
- carbon monoxide causes damage to
the inner walls of arteries
91
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
3 Have balanced diets
92
25.1 Non-infectious diseases
Cardiovascular diseases
Prevention
4 Do exercise regularly
93
25.1 Non-infectious diseases
Diabetes mellitus
• the pancreas does not produce enough
insulin or the body cells cannot
respond to the insulin produced
 highly variable blood glucose level
 severe damage to blood vessels of
the heart, kidneys, eyes and nerves
94
25.1 Non-infectious diseases
Diabetes mellitus
• two forms:
Type 1 diabetes
Type 2 diabetes
95
25.1 Non-infectious diseases
Diabetes mellitus
• Prevalence rate (流行率)
Type 1 diabetes
5–10%
Type 2 diabetes
90–95%
96
25.1 Non-infectious diseases
Diabetes mellitus
• Cause
Type 1 diabetes
Type 2 diabetes
Little or no insulin is Body cells are
produced because insensitive to
the secreting cells
insulin
are destroyed
97
25.1 Non-infectious diseases
Diabetes mellitus
• Risk factor
Type 1 diabetes
Family history
Type 2 diabetes
Family history
Aging
Obesity
Insufficient
exercise
98
25.1 Non-infectious diseases
Diabetes mellitus
• Risk group
Type 1 diabetes
Children and
young adults
Type 2 diabetes
Adults and
obese children
99
25.1 Non-infectious diseases
Diabetes mellitus
• Symptoms
Type 1 diabetes
Type 2 diabetes
Excessive urine production, constant
thirst and hunger, weight loss, fatigue
and blurred vision
100
25.1 Non-infectious diseases
Diabetes mellitus
• Management and control
Type 1 diabetes
Blood glucose
monitoring
Regular injections
of insulin
Healthy eating
Exercise
Type 2 diabetes
Blood glucose
monitoring
Healthy eating
Exercise
101
25.1 Non-infectious diseases
Diabetes mellitus
Type 1 diabetes
Type 2 diabetes
Insulin-dependent Non-insulindependent diabetes
diabetes
102
25.1 Non-infectious diseases
Diabetes mellitus
insulin injection
103
25.1 Non-infectious diseases
Diabetes mellitus
• Prevention
Type 1 diabetes
No prevention
Type 2 diabetes
Eat a healthy
and high fibre
diet
Exercise regularly
Control the body
weight
104
25.1 Non-infectious diseases
1a A
risk factor is anything
that may increase the risk of
developing a disease.
105
25.1 Non-infectious diseases
1b There are four types of risk
factors: biological , genetic
environmental and behavioural
risk factors.
106
25.1 Non-infectious diseases
2a Allergy (overreaction of the
immune system to allergens)
Risk factors: family history and
exposure to allergens
107
25.1 Non-infectious diseases
2a Allergy (overreaction of the
immune system to allergens)
Prevention: avoid exposure to
allergens
- read food label carefully
- avoid contact with dust mites
108
25.1 Non-infectious diseases
2b Cancer (malignant cell growth)
Risk factors: aging , race,
family history, exposure to
carcinogens and smoking
109
25.1 Non-infectious diseases
2b Cancer (malignant cell growth)
Prevention: reduce exposure to
carcinogens and adopt healthy
lifestyles
- wear masks and gloves
when handling construction
materials with asbestos
110
25.1 Non-infectious diseases
2b Cancer (malignant cell growth)
Prevention: reduce exposure to
carcinogens and adopt healthy
lifestyles
- wear sun protection
- avoid early sex and multiple
sex partners
111
25.1 Non-infectious diseases
2b Cancer (malignant cell growth)
Prevention: reduce exposure to
carcinogens and adopt healthy
lifestyles
- do not smoke and avoid
passive smoking
112
25.1 Non-infectious diseases
2b Cancer (malignant cell growth)
Prevention: reduce exposure to
carcinogens and adopt healthy
lifestyles
- include more vegetables in
the diets
113
25.1 Non-infectious diseases
2c Cardiovascular diseases
Risk factors: aging, family history,
high blood cholesterol , obesity,
diabetes mellitus, stress,
insufficient exercise , smoking
and alcohol use
114
25.1 Non-infectious diseases
2c Cardiovascular diseases
Prevention:
- have balanced diets
- exercise regularly
- control the body weight
- do not smoke nor drink wine
115
25.1 Non-infectious diseases
2d Diabetes mellitus
Risk factors (type 1 diabetes):
family history
Risk factors (type 2 diabetes):
family history, aging, obesity ,
insufficient exercise
116
25.1 Non-infectious diseases
2d Diabetes mellitus
Prevention (type 2 diabetes):
- have balanced diets
- exercise regularly
- control the body weight
117
25.2 Prevention of diseases
• increasing use of air travel helps
spread infectious diseases rapidly
118
25.2 Prevention of diseases
• unhealthy lifestyles are related to
the growing incidence of
non-infectious diseases
119
25.2 Prevention of diseases
• different goals:
1 To stop diseases from occurring
2 To detect and treat diseases at
an early stage, before any symptom
or functional loss occurs
120
25.2 Prevention of diseases
• achieve the goals by:
1 offering immunization programmes
2 promoting healthy lifestyles
3 promoting community health
121
25.2 Prevention of diseases
Immunization programmes
• the process of inducing immunity
(免疫性) to a disease in the body
e.g. via a vaccine (疫苗)
contains a weakened or dead
pathogen or a part of pathogen
122
25.2 Prevention of diseases
Immunization programmes
oral form
injection
123
25.2 Prevention of diseases
Immunization programmes
• based on local disease prevalence,
children in HK are offered free vaccines
124
25.2 Prevention of diseases
Immunization programmes
• if the majority of people are immunized,
infectious diseases will not be spread
easily
 health and lives of individuals and
the community are protected
125
25.2 Prevention of diseases
Healthy lifestyles
• adopting healthy lifestyles can help:
- remove sources of infection
- break the transmission link
- prevent risk factors
126
25.2 Prevention of diseases
Healthy lifestyles
• examples:
- have balanced diets
- exercise regularly
- get enough rest
- maintain good personal hygiene
- do not smoke and do not abuse
alcohol or drugs
127
25.2 Prevention of diseases
Community health
• focuses on the protection and
improvement of health of the whole
community rather than individuals
• involves prevention and early detection
of diseases through:
screening for
infections or diseases
disease
surveillance
promotion of health education
128
25.2 Prevention of diseases
Community health
1 Screening for infections or diseases
• testing the whole population
for the presence or absence
of an infection or a disease
e.g. Cervical Screening
Programme
(子宮頸普查計劃)
129
25.2 Prevention of diseases
Community health
1 Screening for infections or diseases
• early diagnosis
 improves cure rate
 helps save health resources by
treating diseases before they progress
130
25.2 Prevention of diseases
Community health
2 Disease surveillance (疾病監察)
• involves the identification of current
incidence and trends of diseases
• helps the health authority to:
- carry out timely investigation
- develop effective strategies for
controlling the diseases
131
25.2 Prevention of diseases
Community health
3 Promotion of health education
• educates the public about:
- the benefits of
adopting healthy
lifestyles and
preventive measures
- receiving early
treatment when required
132
25.2 Prevention of diseases
Community health
• protection and maintenance of
health is both an individual and
public responsibility
133
25.2 Prevention of diseases
1 Immunization is the process of
inducing immunity to a disease
in the body. Immunization can be
done by vaccination .
134
25.2 Prevention of diseases
2 If the majority of people are
immunized, infectious diseases
will not be spread easily in the
community. The health and lives
of individuals and the community
are protected.
135
25.2 Prevention of diseases
3 Examples of healthy lifestyles:
a Have balanced diets
b Exercise regularly
c Get enough rest
136
25.2 Prevention of diseases
3 Examples of healthy lifestyles:
d Maintain good personal hygiene
e Do not smoke and do not
abuse alcohol or drugs
137
25.2 Prevention of diseases
4 Community health is the protection
and improvement of health of
the whole community .
138
25.2 Prevention of diseases
5 Major activities involved in
community health:
a Screening for infections or
diseases
b Disease surveillance
c Promotion of health education
139
1
What is cancer?
Cancer is a malignant tumour resulted
from uncontrolled cell division. The
tumour cells can spread through the
bloodstream and the lymphatic system
to invade other tissues.
140
2
Why are there differences in cancer
occurrence in males and females?
The differences in cancer occurrence
may be related to the differences in
genetic material and behaviour in males
and females.
141
3
Can cancer be prevented?
Cancer can be prevented.
Some preventive measures are:
• For throat and lung cancer: wear
masks and gloves when handling
construction materials with asbestos.
142
3
Can cancer be prevented?
Cancer can be prevented.
Some preventive measures are:
• For skin cancer: wear sun protection.
143
3
Can cancer be prevented?
Cancer can be prevented.
Some preventive measures are:
• For cervical cancer: avoid early sex
and multiple sex partners; have
screening tests for early cellular
changes in cervix;
144
3
Can cancer be prevented?
Cancer can be prevented.
Some preventive measures are:
• For cervical cancer: injection of
Human Papillomavirus vaccines.
145
3
Can cancer be prevented?
Cancer can be prevented.
Some preventive measures are:
• For colon cancer: include more
vegetables in the diets.
146
Diseases
can be
infectious
non-infectious
prevented by
immunization
programmes
community
health
healthy lifestyle
147
non-infectious
examples include
allergies
cancer
diabetes
mellitus
cardiovascular
diseases
148
diabetes mellitus
two types
type 1
diabetes
type 2
diabetes
149