Data from: Socioeconomic status effects on health vary between rural and urban Turkana

Background and objectives: Understanding the social determinants of health
is a major goal in evolutionary biology and human health research. Low
socioeconomic status (often operationalized as absolute material wealth)
is consistently associated with chronic stress, poor health, and premature
death in high income countries. However, the degree to which wealth
gradients in health are universal—or are instead made even steeper under
contemporary, post-industrial conditions—remains poorly understood.
Methodology: We quantified absolute material wealth and several health
outcomes among a population of traditional pastoralists, the Turkana of
northwest Kenya, who are currently transitioning toward a more urban,
market-integrated lifestyle. We assessed whether wealth associations with
health differed in subsistence-level versus urban contexts. We also
explored the causes and consequences of wealth-health associations by
measuring serum cortisol, potential sociobehavioral mediators in early
life and adulthood, and adult reproductive success (number of surviving
offspring). Results: Higher socioeconomic status and greater material
wealth predicts better self-reported health and more offspring in
traditional pastoralist Turkana, but worse cardiometabolic health and
fewer offspring in urban Turkana. We do not find robust evidence for
either direct biological mediators (i.e., cortisol) or indirect
sociobehavioral mediators (e.g., adult diet or health behaviors, early
life experiences) of wealth-health relationships in either context.
Conclusions and implications: While social gradients in health are
well-established across a variety of primate species, and in humans,
across a variety of socioecological contexts, we show that the
relationship between wealth and health can vary within a single
population. Our findings emphasize that changes in economic and societal
circumstances may directly alter how, why, and under what conditions
socioeconomic status is predictive of health.