Mid-Life Vision Impairment and Cognitive Function in Later Life: the Study of Women's Health Across the Nation, Michigan Cohort.

BACKGROUND In older adults, vision impairment (VI) is associated with worse cognitive function. However, the relationship between mid-life vision and future cognitive function remains unknown. METHODS The Study of Women's Health Across the Nation (SWAN), Michigan site, is a longitudinal cohort of mid-life women age 42-52 years at baseline. Presenting Titmus visual acuity (VA) in the better-seeing eye was assessed at baseline and categorized as no or mild VI (VA ≥20/60), or moderate or worse VI (VA <20/60). Cognitive function was measured 8 times over 15 years using the East Boston Memory Test immediate (EBMTi) and delayed (EBMTd) recall and the Digit Span Backwards (DSB) test. Linear mixed models with a random intercept and slope for age were constructed to detect associations between VI at baseline and future repeated measures of cognitive function, adjusting for age, race, education, financial strain, alcohol use, and tobacco use. RESULTS 394 women age 42-52 at baseline with maximum follow-up of 20 years were included in this analysis. After covariate adjustment, moderate or worse VI was associated with lower EMBTi (β= -0.56, p=0.012), EBMTd (β= -0.60, p=0.009) and DSB (β= -0.84, p=0.04). While we detected significant associations between VI and levels of cognitive function scores, rates of cognitive decline as individuals aged did not vary by VI status. CONCLUSION Moderate or worse VI, assessed during mid-life, was associated with lower scores on measures of cognitive function over a 15 year period during which women transitioned from mid-life to older adulthood.