Abstract
OBJECTIVES: Greater lifetime exposure to estrogen may protect women from cognitive decline and dementia later in life. Gender-related social factors also influence women's cognitive outcomes; however, little is known about how these biological and social influences work together. We examined the extent to which cumulative estrogen exposure and lifecourse social exposures jointly influence late-life memory trajectories and dementia risk among a community-based sample of White, Black, and Latina women. METHODS: Participants were 3,688 postmenopausal women in the Washington Heights-Inwood Columbia Aging Project. Lifetime cumulative estrogen exposure was estimated based on age at menarche and menopause, breastfeeding duration, and hormone replacement therapy use. Lifecourse social factors included birth cohort, childhood socioeconomic status (SES), educational and occupational attainment, and later-life income. Multiple-group growth models and Cox regression models were estimated across racial and ethnic groups. RESULTS: Greater lifetime estrogen exposure was independently associated with higher baseline memory performance among Black and Latinx women, slower memory decline among White women, and lower dementia risk among Latinx women. Later birth year and higher lifecourse SES were associated with greater lifetime estrogen exposure, with associations varying in magnitude across racial and ethnic groups. Associations between lifecourse SES and each cognitive outcome were partially mediated by estrogen exposure indicators. DISCUSSION: Cumulative estrogen exposure is socially patterned. We found that lifecourse social factors and estrogen exposure synergistically contribute to women's late-life cognitive health outcomes. Understanding how sex-linked biology and gender-related social forces intertwine is essential for developing interventions to decrease dementia risk among women.