Transcript Health transition and emerging cardiovascular diseases in

Health Transition And
Emerging Cardiovascular
Diseases In Developing
Countries
Dr Sunita Dodani
Department of Epidemiology
University of Pittsburgh
Presentation overview
By the end of this lecture we will learn about
• Epidemiologic & demographic transition in
developing countries
• Examples of demographic transition
• Double burden of diseases
• Causes of Epidemiologic transition
• Available CVD data in Pakistan
• What can be done to reduce the burden
Epidemiologic Transition
A characteristic shift in the disease
pattern of a population as mortality
falls during the demographic transition:
acute, infectious diseases are reduced,
while chronic, degenerative diseases
increase in prominence, causing a
gradual shift in the age pattern of
mortality from younger to older ages
(Omran 1970s)
Rising Life Expectancy
80
(Age in years)
70
60
World
50
Less
Developed
More
Developed
40
30
20
10
0
1950 1960 1970 1980 1990
WHO report, 1997
Epidemiologic Transition
Past, Present & Future
Historical ETs
• rise of infectious disease (~8000 B.C)
• decline of infectious disease & rise of CVD
(19th-20th C)
• decline of cardiovascular disease (late 20th C)
Reverse ETs
• rise of violence (late 20th C)
• resurgent infectious disease (late 20th C)
Possible future ETs
• decline of cancer, dementia, etc. (21st C ?)
(WHO,2000)
Epidemiologic Transition
Birth & Death Rate (per 1000)
Demographic transitions: Indicators over time
(UK as an indicator for the ‘western’ Model)
50
population(Millions)
40
Population
Death Rate
Birth Rate
30
20
Mortality Rate
Fertility Rate
Birth Rate
Size Population
Age Population
10
0
1800
1840
1880
1920
1960
Omran, Millbank Mem Fund Quart, 1971;49,215
Epidemiologic Transition
Models of Demographic transitions
Western
50
45
40
35
30
25
20
15
10
5
0
UK
1800 1840 1880
1880 1920 1960
1960
1800
1840
1920
Accelerated
50
45
40
35
30
25
20
15
10
5
0
Japan
1800 1840 1880
1880 1920 1960
1960
1800
1840
1920
Delayed (Most LDC)
50
45
40
35
30
25
20
15
10
5
0
Sri Lanka
1800
1880
1960
1800 1840 1880 1920 1960
1840
1920
Omran, Millbank Mem Fund Quart, 1971;49,215
Epidemiologic Transition
Recent declines in Fertility rates in developing countries
(United Nations 1993)
1965-70
1985-90
2.3
Prop. Diff
Thailand
6.1
62%
China
6.0
2.3
62%
Bangladesh
6.9
3.6
48%
Turkey
5.6
3.0
46%
Mexico
6.7
3.8
43%
Indonesia
5.6
3.3
41%
Brazil
5.3
3.5
34%
Egypt
6.6
4.4
33%
India
5.7
4.2
26%
Philippines
6.0
4.7
21%
Pakistan
7.0
7.0
0%
Nigeria
6.9
6.9
0%
Epidemiologic Transition
• Epidemics of NCDs are presently emerging,
or accelerating, in most developing countries
• CVDs, cancers, diabetes, neuropsychiatric
ailments and other chronic diseases are major
contributors to the burden of disease
• Infections and nutritional deficiencies are
receding as leading contributors to death and
disability….. Still prevalent
Double Burden of Diseases
(Murray & Lopez, 1996)
Cardiovascular disease transition
•
•
•
•
•
What is current burden of diseases in Asia?
Asia has 50% percent of the total world's
burden of disease.
countries vary on where they are on the
economic development and epidemiologic
transition spectrum.
Leaving China aside, India and the rest of
Asia--a heterogeneous group of 49 countries- about 50% of this burden is from
communicable diseases (such as diarrhea)
Another 40%from noncommunicable diseases
10 percent is from other causes, such as
injuries
(Murray & Lopez, 1990)
Epidemiologic transition
Current & Projected Burden of Diseases
Percent of total burden
China
India
Rest of Asia
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Injuries
Non Communicable disease
Communicable disease
1990
2020
1990
2020
1990
2020
(Murray & Lopez, 1990)
Epidemiologic transition
• Asia is evenly burdened by both the
unfinished agenda of communicable
diseases and the growing burden of
noncommunicable diseases.
• This is different from what we see in the
established market economies, driven by
noncommunicable diseases, and in subSaharan Africa, driven by communicable
diseases.
Epidemiologic Transition
Global burden of disease(1998): Contribution of
low and middle income countries
Low income
high income
World
countries
plus middle income
countries
Total death
Thousands
53,929
Percentage
8,033
45,897
14.9
85.1
7,024
24,693
22.1
77.9
Non communicable disease (NCDs)
Thousands
31,717
Percentage
Total disability-adjusted life years (DALYs) lost
Thousands
1,382,564
Percentage
108,305
1,274, 259
7.8
92.2
DALY loss due to NCDs
Thousands
Percentage
595,363
87,732
507,631
14.7
85.3
Epidemiologic transition
Determinants and dynamics of the CVD
Epidemic in the developing Countries
Health transitions: demographic transitions and epidemiologic transitions
Mortality
Public
Nutrition
Industrialization
Economic
Infant
sanitation technology
and Urbanization
Social &
Mortality
for health
Environmental Housing
care
health
Changes
Life
care
expectancy
Per capita Income
fertility
Wealth
Level of RF: fat,
calories, tobacco,
sedentary habits
NCD
Infectious diseases
Persons at
risk of
developing
NCDs
Increasing
and aging
Population
Determinants and dynamics of the CVD
Epidemic in the developing Countries
Data from South Asian Immigrant studies
• Excess, early, and extensive CHD in persons of
South Asian origin
• The excess mortality has not been fully explained
by the major conventional risk factors.
• Diabetes mellitus and impaired glucose tolerance
highly prevalent.
(Reddy KS, circ 1998).
• Central obesity, ↑triglycerides, ↓HDL with or
without glucose intolerance, characterize a
phenotype.
• genetic factors predispose to ↑lipoprotein(a)
levels, the central obesity/glucose
intolerance/dyslipidemia complex collectively
labeled as the “metabolic syndrome”
Determinants and dynamics of the CVD
epidemic in the developing countries
Other Possible factors
• Relationship between early life characteristics and
susceptibility to NCD in adult hood ( Barker’s
hypothesis)
(Baker DJP,BMJ,1993)
– Low birth weight associated with increased CVD
– Poor infant growth and CVD relation
• Genetic–environment interactions
(Enas EA, Clin. Cardiol. 1995; 18: 131–5)
- Amplification of expression of risk to some
environmental changes esp. South Asian population)
- Thrifty gene (e.g. in South Asians)
CVD epidemic in developing &
developed countries. Are they same?
The determinants of health transition in the
developing countries are similar to those that
charted the course of the epidemics in the developed
countries but dynamics are different.
• The compressed time frame of transition in the
developing countries imposes a large, double burden
of communicable and non-communicable diseases.
• Urbanization in developing countries occurs in settings
of high poverty levels and international debt,
restricting resources for public health responses.
• Prevention began in developed countries when the
epidemic had peaked, and often accelerated a secular
downswing, while the efforts in the developing
countries are commencing when the epidemic is on the
upswing.
CVD epidemic in developing &
developed countries. Are they same?
• Urban populations have higher levels of CVD risk
factors related to diet and physical activity
(overweight, hypertension, dyslipidaemia and diabetes)
• Tobacco consumption is more widely prevalent in rural
population
• The social gradient will reverse as the epidemics
mature.
• The poor will become progressively vulnerable to the
ravages of these diseases and will have little access
to the expensive and technology-curative care.
• The scarce societal resources to the treatment of
these disorders dangerously depletes the resources
available for the ‘unfinished agenda’ of infectious and
nutritional disorders that almost exclusively afflict
the poor
Burden of CVD in Pakistan
Coronary heart disease
Mortality statistics
• Specific mortality data ideal for making
comparisons with other countries are not
available
• Inadequate and inappropriate death
certification, and multiple concurrent causes
of death
Burden of CVD in Pakistan
Population surveys
• Pitfalls in sampling design, sample size standardization
and measurement errors, but still remain the most
important source of information today
National health Survey of Pakistan (NHSP)
• Ischemic Heart Disease (IHD) was reported as 12%
of the adult mortality in Pakistan.
• Tobacco use: 29% and 3.4 % in adult males and
females’ respectively
• Hypertension
- estimated 12 million hypertensives in the country of
the total 120 million population
- Prevalence is 17.9 % of the overall adult
population with 16.4% and 21.5% being the rural and
urban prevalence.
- > 45 years, one in three Pakistanis (33%) are
hypertensive
- 3% adequately controlled
Burden of CVD in Pakistan
• Diabetes
- Pakistan is among the top 10 world nations
for high numbers of people with diabetes
- Prevalence… 10.6%
• Obesity (WHO criteria)
- 1 in 7urban males adults (>15 years) is
obese or overweight with 22% prevalence in
males of 25- 44 years.
- In females, 37% in 24-44 years and 40% in
45-64 years in urban female population
Burden of CVD in Pakistan
Temporal Trends
• Most of our knowledge about prevention and
treatment derives from studies conducted in
developed countries and predominantly among
white populations
• Validated nationally representative estimates
of cause specific mortality and morbidity are
not available for any country in South Asia
• CHD mortality rate of South Asian immigrants
compared with other populations remains high.
• CVDs are major and growing contributors to
mortality and disability in South Asia
Prevention of CVD
• There is an urgent need to establish
appropriate research studies, increase
awareness of the CVD burden, and develop
preventive strategies.
• Prevention and treatment strategies that have
been proven to be effective in developed
countries should be adapted for developing
countries.
• Prevention is the best option as an approach
to reduce CVD burden.
• Do we know enough to prevent this CVD
Epidemic in the first place.