Fertility history and cognition in later life

INTRODUCTION: The accumulation of adverse physiological, socioeconomic and psychosocial factors over the lifecourse may have adverse effects on cognitive function in later life. Such challenges might include stresses resulting from particular fertility pathways, but very little is known about this, especially for men. We investigated the association between fertility history and cognitive functioning in older men and women.

METHODS: The sample included 6132 women and men aged 50+ who participated in the English Longitudinal Study of Ageing. Associations between number of children and timing of births with the level and rate of change of a latent cognitive functioning factor was assessed at five repeated measurement occasions over an 8-year time. Models were controlled for age, socioeconomic position, health, social isolation and control.

RESULTS: Poorer cognitive level was associated with a higher number of children in both men and women. Decline in cognitive functioning was also faster in women with higher number of children. Nulliparity in women and having 1 child in men compared to 2 children were associated with a poorer level of cognitive functioning. Early childbirth was associated with poorer cognitive level in women. Late childbirth was associated with a higher level of cognitive functioning.

CONCLUSIONS: The association between parity and level of cognitive functioning is non-linear so that both high and low parity compared to average parity are associated with poorer cognitive functioning in older age. Early childbirth is also a risk factor for poorer cognitive functioning in older women, whereas those men and women having children late in life have better cognitive functioning. Although socioeconomic factors played an important role in the associations, a considerable amount of covariance remained unexplained. Future studies need to investigate other potential factors. The pattern of the associations suggests that the underlying mechanisms could be related to earlier life events and selection.