Pathways from fertility history to later life health: Results from analyses of the English Longitudinal Study of Ageing

Background: Previous research shows associations between fertility histories and later life health. The childless, those with large families, and those with a young age at entry to parenthood generally have higher mortality and worse health than parents of two or three children. These associations are hypothesised to reflect a range of biosocial influences, but underlying mechanisms are poorly understood.

Objective: To identify pathways from fertility histories to later life health by examining mediation through health-related behaviours, social support and strain, and wealth. Additionally to examine mediation through allostatic load - an indicator of multisystem physical dysregulation, hypothesised to be an outcome of chronic stress.

Methods: Associations between fertility histories, mediators, and outcomes were analysed using path models. Data were drawn from the English Longitudinal Study of Ageing. Outcomes studied were a measure of allostatic load based on 9 biomarkers and self-reported long-term illness which limited activities.

Results: Early parenthood (<20 for women, <23 for men) was positively associated with higher (worse) allostatic load and long-term illness. These associations were partly mediated through wealth, smoking, and physical activity. Wealth, smoking, physical activity, and social strain also mediated associations between larger family size, itself associated with early parenthood, and health outcomes. We found no significant associations between childlessness and allostatic load or long-term illness, except for an association between childlessness and long-term illness among women in models adjusted only for age.

Conclusions: In England early parenthood and larger family size are associated with less wealth and poorer health behaviours and this accounts for much of the association with health. At least part of this operates through stress-related physiological dysfunction (allostatic load).