Physical Activity: A Moderator or Mediator in the Association Between Fertility History and Later Life Health?

Large family size and early parenthood have been associated with adverse health outcomes in old age whereas there is increasing evidence of the beneficial effects of physical activity. We examined the extent to which physical activity might mediate and/or moderate later life health disadvantages related to a high number of children and early parenthood. We used data from five waves of the English Longitudinal Study of Ageing collected in 2002–2010 (n = 11,233 in wave 1). Latent change score modelling was used to assess the direction of the association between physical activity and functioning. An interaction term of physical activity and fertility history was added in latent growth curves for functional limitation. The models were adjusted for age, gender, smoking, educational attainment, occupational status and wealth in wave 1, with whether married and depressive symptoms included as time-varying covariates. The models suggested that physical activity serves as a mediator in the association between fertility history and the level of later life functioning. However, there was no effect of fertility history on changes in physical activity or functional limitation. Among those who were physically active, functional limitations remained at a considerably lower level and high number of children and early parenthood were not associated with poorer levels of health. Physical activity thus moderates the level of health disadvantages related to high number of children and parenthood.