A paternal grandfather's access to food during their pre-pubertal slow growth period (ages 9 to 12 years) is associated with mortality risk in their male, but not female, grandchildren. The findings are published in Nature Communications this week. This study in a large, three-generational cohort expands on previous work and supports the hypothesis that environmental exposures in one generation may influence health outcomes in subsequent generations. However, the study does not determine a potential mechanism for this relationship.
Denny Vagero and colleagues collected information on the yields of harvests for the regions in Sweden included in the Uppsala Birth Cohort Multigeneration Study from 1874-1910. These data were used to estimate how difficult it was for the grandparents (9,039) to access food during their slow growth period. Using data on mortality from 1961-2015 for their grandchildren (11,561), the authors found that paternal grandfathers entering their slow growth period during years when harvests had unusually high yields were correlated with a higher all-cause mortality risk and a higher risk of dying from cancer in their grandsons. However, the association was not seen in their granddaughters.
Although these results support the idea of transgenerational epigenetic inheritance (when the effects of an environmental exposure are inherited via epigenetic modifications in the germline), they only provide indirect evidence for this hypothesis. Further studies showing a direct effect on epigenetic markers in the germline and transmission of such markers over three generations would be required to establish a direct causal link between grandfathers' access to food and their grandsons' mortality risk.