Purpose: We sought to examine the association between birthweight in offspring and mortality in their parents. Distinguishing between risks of outcomes in mothers from fathers potentially provides clues as to the relative roles of genetic versus nongenetic mechanisms underlying these associations.
Methods: We studied total and cause-specific mortality in a population-based cohort of 37,718 mothers and 38,002 fathers whose offspring were delivered in West Jerusalem during 1964-1976, after an average follow-up of 34.12 years.
Results: Hazard models controlling for sociodemographic and lifestyle characteristics indicated a U-shaped relationship between offspring's birthweight and overall mortality, deaths from coronary heart disease, circulatory and other non-neoplastic causes in their mothers. Greater rates of mortality from coronary heart disease were observed among mothers who gave birth to babies with low (hazard ratio [HR], 2.13; 95% confidence interval [CI], 1.40-3.25) and high birthweight (HR, 1.98; 95% CI, 1.36-2.88), as compared with mothers whose offspring weighed 2500-3999 g at birth. Adjustment for maternal pre-eclampsia slightly attenuated these results. Multivariate models indicated a negative linear relationship (HR, 0.95; 95% CI, 0.91-0.99) between offspring's birthweight and overall mortality in their fathers. Unlike the association in mothers, the relation was noted primarily with deaths from "other causes."
Conclusions: Birthweight of offspring is associated with parental mortality although the relation differs for fathers and mothers. These findings broaden previous observations that intra-uterine events have long-term consequences for adult health and support the need to explore genetic and/or environmental mechanisms underlying these associations.