Cognitive Aging in Same- and Different-Sex Relationships: Comparing Age of Diagnosis and Rate of Cognitive Decline in the Health and Retirement Study.

INTRODUCTION: The ongoing marginalization of lesbian, gay, and bisexual people has been hypothesized to produce poorer late-in-life cognitive outcomes, according to mechanisms posited by minority stress and allostatic load theories. Yet the existence of those outcomes remains understudied, and results of existing studies have been contradictory. Using a population-based longitudinal aging study, this paper will compare age at diagnosis of Alzheimer's disease (AD) or a related dementia and rates of cognitive decline between participants in same-sex relationships (SSRs) and different-sex relationships (DSRs).

METHODS: The study used longitudinal cognitive-health data from the Health and Retirement Study (HRS; 1998-2018; N = 26,344) to analyze the onset of cognitive impairment and AD/dementia and the rates of cognitive change between participants in SSRs and those in DSRs. We hypothesized that SSR participants would have worse overall cognitive functioning in old age and would experience earlier onset of cognitive impairment. Using multiple regression, we compared the ages at which participants in SSRs and DSRs first reported AD or dementia diagnoses and the ages at which they first scored below cutoffs for cognitive impairment, not dementia (CIND) and possible dementia as determined using the cognitive assessment. The study then compared rates of cognitive decline over time across the SSR and DSR groups, including stratified analyses by education, race/ethnicity, wealth, and sex/gender.

RESULTS: Participants in SSRs reported dementia diagnoses (β = -12.346; p = 0.001), crossed the threshold into CIND (β = -8.815; p < 0.001) and possible dementia (β = -13.388; p < 0.001) at a younger age than participants in DSRs. When adjusted for covariates, participants in SSRs also had lower cognition at baseline (β = 0.745; p = 0.003), though having slower rates of cognitive decline when SSR was interacted with time (β = 0.066; p = 0.003). In separate analyses, cognitive differences for SSR participants were only found in participants without undergraduate degrees, with below-median household incomes, and women.

CONCLUSION: Our findings support theories suggesting that marginalization and stigma cause premature cognitive impairment. Findings also suggest that higher education might mitigate the adverse effects of sexuality-minority status on cognitive aging. Results do not support these theories' claims of more rapid cognitive decline; the lower slopes of cognitive decline with time are compatible with the possibility of slower rates of decline for aging individuals in SSRs.