Early life stress and later health

Early life conditions have profound long-term health consequences over the life course. However, previous studies concentrate almost exclusively on the detrimental impact of fetal and early childhood malnutrition on adult health; by contrast, little attention has been paid to late childhood nutrition, which is also highly relevant in one’s growth trajectory and health outcome. This is the case especially in developing countries. We use data recently collected from a nationally representative sample survey of the Chinese population to explore the impact of late childhood nutrition intakes on adult health. The underlying linkage between childhood nutrition, adult height and a broad range of subjective and objective health indicators will be examined.

Unlike previous migration studies which mainly focus on individual migration, this article examines the long-term mortality consequences of childhood migration and resettlement. Using a unique Chinese historical population database, we trace 30517 males from childhood onwards between 1792 and 1909, 542 of whom experienced childhood migration. We apply discrete-time event-history analysis and include a fixed effect of common grandfather to account for unobservable characteristics of the extended family. We also explore the influence of social networks on early-life migration experience by including kin network at destination. Our findings suggest that migration in childhood has substantial long-term effects on survivorship in later ages. From age 16 to 45, kin network at destination mediates the negative effects of childhood migration and lowers mortality risks. Moreover, child migrants who survive to older ages subsequently experience lower mortality. Such findings contribute to a better understanding of the implications of social behavior and social context for human health.

Early-life effects on old-age mortality and how these effects may be
mediated by intermediate events are studied. Data come from 19th century northern Sweden in the form of digitized life trajectories from the Demographic Data Base, Umeå University, more specifically the Sundsvall region. The causal pathway from an exposure to an outcome is a topic that lately has been attracting strong attention. Of special interest is how to measure and estimate the mediating effect of factors on the causal pathway. We use infant mortality (IMR) at birth as a proxy for early-life conditions, and the mediator is socio-economic status (SES) in mid-life. The research question is thus: Is there an effect of IMR at birth on life expectancy after age 60, and if so, is this effect mediated by SES in mid-life, say around the age of 50?

We find strong direct effects from early-life conditions measured by IMR, but the indirect effects under investigation are weak.

There is growing evidence that maternal psychological stress during pregnancy, negatively affects a wide variety of offspring outcomes. Animal studies suggest that negative influences of maternal stress during pregnancy persist across multiple generations, but there is little direct evidence confirming that it is present among human populations. This study draws evidence on the intergenerational influences of maternal stress from the Kwangju uprising (May 18-27), arguably the bloodiest incidence that has occurred in South Korea since the end of the Korean War in 1953. The micro files of the 2000 and 2002 Vital Statistics of South Korea are utilized for the study. The results of difference-in-difference estimations suggest that in-utero exposure to the Kwangju uprising significantly diminished the offspring birth weight and length of gestation. The impact of exposure to maternal stress differs by stage of pregnancy when the shock is received. Exposure to stress during the second trimester of pregnancy exerted the strongest negative effect on grandchildren’s birth weights. As for the length of gestation, the second and third trimesters were equally critical.