Early Indicators, Intergenerational Processes, and Aging

Project Outcomes Statement

Since its inception in 1997, the Early Indicators (EI) project has made many discoveries about the longitudinal determinants of retirement and of chronic disease and death at older ages by studying aging processes among Union Army veterans of the US Civil War, a group that mostly reached age 65 between 1885 and 1912. These discoveries were possible because of the creation of longitudinal data sets that follow more than 76,000 Union Army recruits from military service back to childhood and forward to death and contain about 15,000 observations per person. The final installment of this long-running project examined the intergenerational determinants of later longevity and socioeconomic status.

The project has documented how a health shock cascades from father to child, and from father to grandchild and provided indirect evidence on the mechanisms. We found indirect evidence of both epigenetic and socioeconomic transmission with transmission depending on the initial stressor.
When the ancestral stressor was the father’s ex-POW status in the US Civil War (1861-5), it was associated with the longevity after age 45 of sons born after the war and of the male-line grandsons of these sons.

It was uncorrelated with the longevity of daughters, granddaughters, or female-line grandsons.

We ruled out transmission through socioeconomic channels and direct cultural transmission. An epigenetic explanation is most consistent with the observed male-line transmission at epigenetically sensitive ancestral ages and mediation by own late gestational conditions.

Consistent with epigenetic reprogramming depending on the in-utero environment, the association between veteran’s ex-POW status and that of his male-line descendants declines across generations. When the stressor was whether the father was wounded in the war, we found socioeconomic effects among fathers and mortality patterns of children by paternal wound status and by paternal age when wounded consistent with a socioeconomic explanation.

The project also documented the intergenerational and life course reach of early life and paternal health and socioeconomic status and differences in transmission by ethnicity and race.

All of the Union Army data sets developed over the life of this project, along with their detailed documentation, are available online at:
https://www.nber.org/programs-projects/projects-and-centers/union-army-data?page=1&perPage=50

https://www.nber.org/programs-projects/projects-and-centers/union-army-data/union-army-data-veterans-children-census

The datasets have also been submitted and will be available at ICPSR: https://www.icpsr.umich.edu/web/pages/.