Racial disparities in Alzheimer’s disease and related dementias (ADRD) have been increasingly linked to social and structural determinants of health (SSDoH). Economic stability (ES) and health care access (HCA) are two major SSDoH domains that may play an important role in shaping late-life brain health. Research has shown that living in an environment with greater economic or healthcare resources is associated with better baseline cognitive functioning, although our understanding of how these SSDoH domains influence longitudinal cognitive change within racially diverse samples is limited. Additionally, it is relatively unknown whether there may be interactive effects between SSDoH domains on cognitive functioning over time. For example, low ES may exacerbate the deleterious effects of insufficient HCA on cognitive trajectories. The current study examined the main effects and interaction between ES and HCA on 10-year change in memory functioning in a large sample of community-dwelling older adults.

Participants included 701 Black/African American and 1,804 White older adults without dementia who were enrolled in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (age M=73.5; 76% women). A factor analysis of baseline ACTIVE data, public U.S. census, and industry classification data produced the ES and HCA composites. Episodic memory was measured as a composite factor score consisting of the Rivermead Behavioral Memory Test, Rey Auditory Verbal Learning Test, and Hopkins Verbal Learning Test. Multilevel models with age as the timescale tested the main effects and interaction of ES and HCA on memory trajectories across the whole sample and within each racial group. Covariates included race (whole sample), sex, self-reported general health, health insurance status, education, vocabulary, depressive symptoms, visual acuity, recruitment wave, study site, training group, and practice effects.

Analyses across the whole sample revealed there was a significant ES x HCA interaction on memory level (β = .09, p = .01), but not memory trajectories (β = .003, p = .42); having higher levels of both ES and HCA were associated with higher memory performance across ages. Main effect models showed no associations between ES or HCA (βs ≤ -.007, ps ≥ .08) on memory levels or trajectories across the whole sample. Race-stratified models revealed no significant ES x HCA interactions within Black/African American or White older adults (βs ≤ .008, ps ≥ .40). However, main effects models showed that higher ES levels were associated with slower age-related linear decline in memory within Black/African American (β = .03, p = .006), but not White older adults (β = -.0003, p = .52). There were no main effects of HCA within race stratified groups (βs ≤ ­-0.01, ps ≥ .07).

ES and HCA exhibited a combined beneficial effect on memory level across the sample, but only greater ES protected against age-related memory decline in Black/African American older adults. Reducing community-level disparities in ES generated by structural racism could have important downstream effects that mitigate racial disparities in ADRD. Future work should explore the sociobiological mechanisms underlying the particular relevance of ES on age-related memory decline.