Health and Aging in Africa: Longitudinal Studies in three INDEPTH Communities

Over the last decades, countries in Sub-Saharan Africa (SSA) have experienced a demographic and epidemiological transition with declines in mortality from infectious diseases and increases in the prevalence of non-communicable disease. Many adults in SSA are now surviving with chronic diseases whether they are communicable or non-communicable. While we have data resources to understand the challenges of aging in the context of high income countries, little is understood of the nature of aging in the SSA context. Our project aims to establish longitudinal surveys of health, aging, and wellbeing allowing estimation of the prevalence and incidence of major chronic conditions in 3 population-based health and demographic surveillance sites (HDSS) at different stages of health transitions (in South Africa, Ghana and Tanzania) in adults age 50 and over (n=12,000). Participants are surveyed in each year 2014 to 2017 with continuous mortality monitoring.

Baseline surveys are introduced in one country per year, with South Africa in year 2, Ghana in year 3 and Tanzania in year 4. A 3 year follow up occurs in South Africa in year 5. Through intensive monitoring and follow up, migrants will be maintained in the cohort at very high levels. Our survey is comparable to that of the Health and Retirement Study (HRS) and sister surveys, yet is adapted to capture characteristics specific to SSA. With 4 subprojects on 1.physical and cognitive function, 2.cardiometabolic disorders, 3.HIV, and 4.economic well being, our goal is to understand the determinants of health in the elderly and in turn find the consequences of health for productivity and wellbeing. Our specific aims are: 

1. To establish three cohorts of 4,000 men and women aged 50 and over based on random stratified samples of the HDSS populations in the INDEPTH sites of Agincourt in South Africa, Navrongo in Ghana and Ifakara in Tanzania (n=12,000). A clinical substudy is conducted in a 10% subsample to look intensively at HIV and CVD.
2. To identify social, economic and biologic predictors of mortality, the incidence of disease (particularly cardiovascular disease and HIV) and changes in physical and cognitive function over three years.
3. To identify the effects of ill health on the economic wellbeing and productivity of the three cohorts. 

We aim to identify the ways in which behavioral and biologic risks are embedded in the social and policy context and are driven by social and economic conditions. Health policies, in the broadest sense, will need to rest on a strong evidence base and our study will provide valid and reliable assessments of phenotypic disorders and risk factors.