The impact of female reproductive period length, parity, and hormonal replacement therapy on cognitive performance

Abstract

AbstractBackgroundSome evidence suggests that Alzheimer’s disease and cognitive decline are more prevalent in women and that risk factors specific to the female sex could be involved. The aim of this study is to estimate the association between the length of female reproductive period, parity, hormonal replacement therapy (HRT) and later life cognition in a large cohort of Brazilian older adults.MethodWe analyzed cross‐sectional data from 4,558 women and 3,799 men. Cognitive function was measured through a global cognitive score composed of orientation, verbal fluency, and memory tests. Age at menarche and menopause, parity and use of HRT were self‐reported. Multiple linear regression analyses were performed to identify hormone related factors associated with current cognitive functioning in women, adjusting for relevant covariates. Afterwards, we performed an analysis among men for number of children.ResultHigher parity was associated with worse cognitive functioning (β = ‐0.01, p < 0.001), while lengthier reproductive life (β = 0.00, p = 0.001) and HRT use (β = 0.04, p = 0.023) were associated with better cognitive performance. We performed a sensitivity analysis, after dividing women into parity groups. When compared with 0 births, the group with 1‐5 had better cognition (β = 0.08, p = 0.001), while the other groups displayed no differences. After excluding nulliparous women, compared to women with 1‐5 births, women with 6‐10 (β = ‐0.1, p < 0.001) and 11+ births (β = ‐0.16, p < 0.001) had an increasingly worse cognitive performance. We also analyzed number of children data for men, which had no impact on cognition (β = ‐0.00, p = 0.688).ConclusionResults indicate a protective effect on cognition of longer reproductive life, HRT use and 1‐5 childbirths, when compared to being nulliparous or having 6+ births. Among men, number of children was not associated with cognitive performance. These findings indicate a positive effect of estrogen on the brain, unrelated to current offspring. This effect might be mitigated by frequent pregnancies, but a smaller number of childbirths may not be enough to exert an impact, while bringing positive psychological effects that are protective for cognition.