The effect of early-life and mid-life factors on old age mortality

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.