PURE (Prospective Urban and Rural Epidemiological Study)

Participating PURE SITES (To view participating countries move mouse over the yellow stars.)

 

PURE (Prospective Urban and Rural Epidemiological Study) 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, & increases in chronic diseases. These changes are attributed to economic development, & societal & lifestyle changes associated with urbanization. Low & middle income countries (LIC & MIC) are undergoing several transitions (economic, nutrition, urbanization), which collectively affect health, giving rise to marked increases in obesity, diabetes, & 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. In Phase 1 (last 4 years) we developed and implemented the protocol in 5 states in India, (where 20,000 subjects have been recruited), & 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, & psychosocial factors. Anthropometric, BP & 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. 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). 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 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, & CVD rates, the relative contribution of individual (lifestyle) & 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.