Fathers Matter: Why It's Time to Consider the Impact of Paternal Environmental Exposures on Children's Health

Abstract

Purpose: Despite accumulating evidence from experimental animal studies showing that paternal environmental exposures induce genetic and epigenetic alterations in sperm which in turn increase the risk of adverse health outcomes in offspring, there is limited epidemiological data on the effects of human paternal preconception exposures on children's health. We summarize animal and human studies showing that paternal preconception environmental exposures influence offspring health. We discuss specific approaches and designs for human studies to investigate the health effects of paternal preconception exposures, the specific challenges these studies may face, and how we might address them.

Recent findings: In animal studies, paternal preconception diet, stress, and chemical exposures have been associated with offspring health and these effects are mediated by epigenetic modifications transmitted through sperm DNA, histones, and RNA. Most epidemiological studies have examined paternal preconception occupational exposures and their effect on the risk of birth defects and childhood cancer; few have examined the effects of low-level general population exposure to environmental toxicants. While the design and execution of epidemiological studies of paternal preconception exposures face challenges, particularly with regard to selection bias and recruitment, we believe these are tractable and that preconception studies are feasible.

Summary: New or augmented prospective cohort studies would be the optimal method to address the critical knowledge gaps on the effect of paternal preconception exposures on prevalent childhood health outcomes. Determining if this period of life represents a window of heightened vulnerability would improve our understanding of modifiable risk factors for children's health and wellbeing.

Keywords: Children’s health; chemical exposures; epidemiology; epigenetics; paternal; preconception; prenatal.

Figure 1. Example illustrating the potential for selection bias to influence studies of paternal preconception environmental exposures and child health

In this figure, E is the exposure of interest (e.g., paternal smoking), S is some selection factor of study eligibility, D is a child health outcome, and U is and unknown or unmeasured factor that causes both selection and the child health outcome.