Inflammatory mechanisms underlying the effects of everyday discrimination on age-related memory decline

Abstract

Background/objectives: Previous research suggests that everyday discrimination is associated with worse episodic memory and partially mediates Black-White disparities in memory aging. The biological mechanisms underlying the link between everyday discrimination and memory are unclear but may involve inflammatory processes. This study aimed to determine whether systemic inflammation, indexed by blood levels of C-reactive protein (CRP), mediates associations between everyday discrimination and episodic memory over 6 years.

Design: A longitudinal mediation model quantified associations between baseline everyday discrimination, 4-year change in CRP, and 6-year change in episodic memory.

Setting: The Health and Retirement Study (HRS).

Participants: 12,624 HRS participants aged 51 and older.

Measurements: Everyday Discrimination Scale, high-sensitivity CRP assays of dried blood spots, composite scores of immediate and delayed recall of a word list.

Results: Black participants reported greater everyday discrimination. Greater discrimination was associated with lower baseline memory and faster memory decline. Higher CRP at baseline partially mediated the negative association between discrimination and baseline memory, but CRP change did not mediate the association between discrimination and memory decline.

Conclusion: This U.S.-representative longitudinal study provides evidence for deleterious effects of discrimination on subsequent episodic memory. The fact that elevated CRP only partially explained the concurrent association between discrimination and memory highlights the need for more comprehensive investigations of biological mechanisms underlying the link between social stress and age-related memory decline in order to better characterize potential intervention targets to reduce racial inequalities in memory aging.

Keywords: Aging; C-reactive protein; Episodic memory; Race; Social stress.

Figure 1.

Schematic of the longitudinal mediation model. Solid lines indicate significant (p<0.05) paths, and dotted lines indicate nonsignificant paths. Values shown are standardized estimates (standard errors). For simplicity, race, ethnicity, and covariates (i.e., age, gender, education) are not shown. Note. CRP = C-Reactive protein.