The specific aims include:
Specific Aim 1: Analyze similarities and differences in age trajectories of cognition among these three adult populations and compare these patterns with high- and middle-income populations. Hypothesis: Overall and domain-specific levels of cognitive function are lower in lower-income countries and accelerated cognitive decline begins at younger ages compared to patterns observed in middle- and high-income countries.
Specific Aim 2: Utilize the unique longitudinal information for the three populations to estimate patterns and changes in the age trajectories of cognition as a function of socioeconomic status, access to resources and exposure to environmental and health shocks during the life course. Hypothesis: Exposure to more adverse environments and frequent shocks throughout the life-course is associated with increased risk of cognitive impairment among aging individuals. We also hypothesize that these low-income populations exhibit a different life-course trajectory of cognitive decline, with significantly earlier onset, different gender patterns, and stronger mortality selection at earlier ages.
This projects Overall Aim is to lay foundations for a program application to examine for the first time individual variation and age-related changes in cognitive health in mature adults across non-WEIRD (Western, Educated, Industrialized, Rich, Democratic), low-incomce populations with the ultimate goal to understand if cognitive aging follows universal trajectories and/or is determined by environmentally dependent mechanisms. The project focuses on comparative analysis of longitudinal data on cognition among mature adults using data sets covering substantial segments (at least two decades) of the life-cycle in three very distinct relatively low-income populations in Bolivia, Guatemala, and Malawi.