Background:
For most populations, the last century has witnessed dramatic improvements in health.
Life expectancy has increased from a global average of 46 years in 1950 to 66 years
in 1998. During the 1st half of the century, developed countries experienced rapid
declines in deaths from infections, childhood diseases, and increases in chronic
diseases. These changes are attributed to economic development, and societal and
lifestyle changes associated with urbanization. Low and middle income countries
(LIC and MIC) are undergoing several transitions (economic, nutrition, urbanization),
which collectively affect health, giving rise to marked increases in obesity, diabetes,
and CVD. It is expected that by 2020, >85% of global CVD will be in developing
countries. Therefore there is an urgent need to understand how societal changes
in LIC, MIC, and high IC (HIC) increase chronic diseases, e.g. CVD, in order to
develop strategies that mitigate these processes. To do so a global research program
that includes investigation of macro-environmental changes (urbanization and other
societal factors) and individual level factors (lifestyle, metabolic and genetic)
is required.
Hypothesis:
We hypothesize that maladaptation to urbanization (with increased energy intake and decreased energy expenditure)
is the proximate cause of obesity, which leads to elevated traditional risk factors
(dyslipidemia, dysglycemia, hypertension).The risk factors interact with genetic
and psycho-social factors resulting in increased CVD.
The delineation of societal and biologic pathways, from proximate environmental
causes (maladaptation to urbanization) to primordial risk factors (obesity), and
primary risk factors (dysglycemia, dyslipidemia, hypertension) and clinical disease
will facilitate development of interventions to mitigate the global rise of obesity,
DM and CVD.
Project Overview:
We will establish urban and rural cohorts to
track changing environments, societal influences on lifestyle, risk factors and
CVD, utilizing periodic standardized data collection in multiple communities from
15 countries (Argentina, Brazil, Canada, Chile, China, Colombia, India, Iran, Poland,
S. Africa, Sweden, Tanzania, Thailand, UAE, Zimbabwe) representing every major region
of the world involving a total of about 120,000 individuals.
Phase 1
In Phase 1 (last 4 years) we developed and implemented the protocol
in 5 states in India, (where 20,000 subjects have been recruited), and adapted
the protocol to 5 other countries where pilot studies in 50 to > 1200 subjects
have been done. Information was collected on medical conditions, demography, diet,
physical activity, stress, and psychosocial factors. Anthropometric, BP and
ECG measurements were made. Blood was collected and stored at -70 0 C. Country specific
food frequency questionnaires have been developed and are being validated.
Phase 2
In Phase 2, a vanguard phase with the recruitment of about 1000
individuals from each country leading to further refinement of our protocol, will
be undertaken (total numbers, including Phase 1 subjects of 35,000 people).
Phase 3
In Phase 3 an additional 90,000 individuals (half urban and half
rural) will undergo detailed health assessment. This information will allow cross-sectional analyses.
Phase 4
Phase 4 consists of follow-up of all subjects with periodic assessment
for risk factors for 9 to 12 years to evaluate:
- whether societal changes influences lifestyles
and risk factors,
- whether this leads to levels of obesity, diabetes, the INTERHEART
score, and CVD rates,
-
the relative contribution of individual (lifestyle)
and community level factors (built environment, increasing mechanization, access
to health care) to variations in risk factors and CVD rates.
Our study can affect health strategies for prevention in
Canada as well as globally by influencing policies and legislation related to urban
development, nutrition and the environment, which affect health.