Life course financial mobility and later-life memory function and decline by gender, and race and ethnicity: an intersectional analysis of the US KHANDLE and STAR cohort studies.

Background: Intersectionality has rarely been considered in research studies of cognitive ageing. We investigated whether life-course financial mobility is differentially associated with later-life memory function and decline across intersectional identities defined by gender, and race and ethnicity.
Methods: Data were from two harmonised multiethnic cohorts (the Kaiser Healthy Aging and Diverse Life Experiences cohort and the Study of Healthy Aging in African Americans cohort) in northern California, USA (n=2340). Life-course financial mobility, measured using a combination of self-reported financial capital measures in childhood (from birth to age 16 years) and later adulthood (at the cohort baseline) was defined as consistently high, upwardly mobile, downwardly mobile, or consistently low. We clustered individuals into 32 strata representing intersectional identities defined by life-course financial mobility combined with gender, and race and ethnicity. Verbal episodic memory was assessed using the Spanish and English Neuropsychological Assessment Scales over four waves from 2017 to 2023. Adjusted mixed-effects linear regression models were estimated with and without fixed effects of gender, race and ethnicity, and financial mobility, to evaluate whether the random effects of the intersectional identity strata contributed variance to memory beyond individual fixed effects.
Findings: Mean age was 73·6 years (SD 8·1). Of 2340 individuals, 1460 (62·4%) were women, 880 (37·6%) were men, 388 (16·6%) were Asian, 1136 (48·5%) were Black, 334 (14·3%) were Latinx, and 482 (20·6%) were White. Consistently low and downwardly mobile financial capital were strongly negatively associated with later-life memory at baseline (-0·162 SD units [95% CI -0·273 to -0·051] for consistently low and -0·171 [-0·250 to -0·092] for downwardly mobile), but not rate of change over time. Intersectional identities contributed 0·2% of memory variance after accounting for the fixed effects of gender, race and ethnicity, and financial mobility.
Interpretation: Consistently low and downward life-course financial mobility are associated with lower later-life memory function. Intersectional identities defined by financial mobility in addition to gender, and race and ethnicity, contribute negligible additional variance to later-life memory in this study setting.
Funding: US National Institute on Aging, US National Institutes of Health.
Competing Interests: Declaration of interests PG and LCK report funding from the US National Institute on Aging at the US National Institutes of Health. ERM reports funding from the US National Institute on Aging at the US National Institutes of Health and the California Department of Public Health, consulting fees from consulting on grants funded by the US National Institutes of Health, honoraria for research talks at Columbia University and the XVII Symposium on Sleep and Breathing, and serving on the leadership committees for the Methods in Longitudinal Research on Dementia (MELODEM) Initiative and the Advanced Psychometrics Methods in Cognitive Aging Conference. RLP reports funding from the US National Institute on Aging at the US National Institutes of Health, honorarium for a symposium presentation at the University of California Davis Alzheimer’s Disease Research Center, and travel support from the Alzheimer’s Association Interdisciplinary Summer Research Institute. CES reports funding from the US National Institute on Aging at the US National Institutes of Health and serving as chair of the ISTAART PIA to Elevate Early Career Researchers (PEERs) and co-chair of the Sex and Gender Special Interest Group of the Diversity and Disparities PIA in ISTAART. RAW reports funding from the US National Institutes of Health and the Alzheimer’s Association, consulting fees from the University of Colorado and Genentech Pan Neuro, and serving on the Observational Monitoring Board for the Efficacy and Durability of Initial Combination Therapy for Type 2 Diabetes (EDICT) study and the Diabetes Prevention Program Outcomes Study (DPPOS), and the Data Monitoring Committee of the Add Health Study. XY, JA-R, PAA-H, CV-C, and EM declare no competing interests.
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