Female-specific factors are associated with cognition in the UK Biobank cohort.

BackgroundRelative to males, females are at a higher risk of developing age-related neurocognitive disorders including Alzheimers disease. Emerging evidence suggests that reproductive life events such as pregnancy and hormone use may influence females cognition later in life. Yet, females health has historically been understudied, and little is known about the relationship between female-specific factors and cognition. MethodsUsing multiple linear regression, we investigated the associations between reproductive history, exogenous hormone use, apolipoprotein (APOE) {varepsilon}4 genotype and cognition in 221,124 middle-to older-aged (mean age 56.2 {+/-} 8.0 years) females from the UK Biobank. Performance on six cognitive tasks was assessed, covering four cognitive domains: episodic visual memory, numeric working memory, processing speed, and executive function. ResultsA longer reproductive span, older age at menopause, older age at first and last birth, and use of hormonal contraceptives were positively associated with cognitive performance later in life. Number of live births, hysterectomy without oophorectomy and use of hormone therapy showed mixed findings, with task-specific positive and negative associations. Effect sizes were generally small (Cohens d < 0.1). While APOE {varepsilon}4 genotype was associated with reduced processing speed and executive functioning, in a dose-dependent manner, it did not influence the observed associations between female-specific factors and cognition. ConclusionOur findings support previous evidence of associations between a broad range of female-specific factors and cognition. The positive association between a history of hormonal contraceptive use and cognition later in life showed the largest effect sizes (max. d = 0.1). Future research is needed to investigate the effects of sex hormone exposure and cognition to develop a better understanding of females brain health.