Health and human development: understandings from life-course research.

It is now well understood that life-course factors affect a diverse range of outcomes, from general well-being to physical functioning and chronic diseases. Exposure to both beneficial and adverse circumstances over the life course will vary for each individual and will constitute a unique life exposure trajectory, which will manifest as different expressions of health and well-being. Here, we present a 3-fold model of life-course influences on health: latency, cumulative, and pathway. By latency we mean relationships between an exposure at one point in the life course and the probability of health expressions years or decades later, irrespective of intervening experience. Cumulative refers to multiple exposures over the life course whose effects on health combine. Finally, pathways represent dependent sequences of exposures in which exposure at 1 stage of the life course influences the probability of other exposures later in the life course, as well as associated expressions. Evidence demonstrating these relationships suggests that, without a consideration of early life as well as adult life experience, policies designed to improve health status tend to overlook root causes.