A life course perspective on the effects of cumulative early adversity on health - Summary Chronic diseases of aging affect millions of Americans, with consequences for health care, economic growth, and healthy aging. A key driver of these effects is exposure to adverse environments during childhood. In the initial grant period, we tested leading models to understand and mitigate these effects in a non-human primate model. Contrary to popular “mismatch” models, we found little evidence that developmental responses to early-life adversity prepare individuals for continued adversity in adulthood. Instead, an accumulation of adverse circumstances in early life had negative effects on a wide range of health and aging outcomes in adulthood, including rates of biological aging and all-cause mortality. Individuals were partly protected from these outcomes if they had strong social support and/or high social status in adulthood. In this renewal, we turn our attention to adolescence as an additional sensitive period, beyond early life. Adolescence is a time of rapid neural, behavioral, and physiological development, and it may also represent key period to reset from harsh early life conditions. Working from leading theory, we hypothesize that individuals will be most sensitive to environmental conditions, including both adverse and protective factors, during periods of rapid developmental change. Further, we predict that adversity across multiple sensitive periods, including early life and adolescence, will be especially detrimental to adult health and aging. Our objectives are to: (i) compare sensitivity to adverse conditions in early-life and adolescence for multiple types of adversity and a wide range of health outcomes from early adulthood to old age; (ii) test how adversity in early life and adolescence interact to predict development, health, and aging; and (iii) identify the developmental periods when individuals are most sensitive to protective factors, such as social support. We will accomplish these goals by working in our innovative non-human primate model in Kenya, which has 55 years of continuous, fine-grained, prospective, longitudinal, data on exposures to adverse environments and multiple dimensions of health from early adulthood to old age—data that do not yet exist in current USbased cohorts (current studies focusing on adolescence are constrained to retrospective, and/or self-reported designs, lack data on early life conditions, or do not have outcome data beyond early adulthood). By testing when in development individuals are most sensitive to adverse and protective factors, we will help pinpoint when in life interventions to alleviate the adversity will be most effective. Further, by focusing on fundamental hypotheses for when sensitive periods occur and how evolution shapes early life effects on adult health, we will help shift the debate from understanding when these effects occur to how to best harness developmental responses to mitigate their negative consequences for chronic disease risk.
