Discrimination and allostatic load in black middle-aged and older adults: A systematic review and meta-analysis

BACKGROUND: Perceived discrimination has been associated with elevated allostatic load (AL), but findings among Black middle-aged and older adults are inconsistent. A focused synthesis is lacking, limiting understanding of how discrimination becomes biologically embedded. This systematic review and meta-analysis aim to clarify the discrimination and AL relationship in Black individuals during aging and highlight key methodological and contextual factors. METHODS: A systematic search of seven databases following PRISMA guidelines included studies on discrimination and AL in Black adults aged 40 and older. AL measures were multisystem indexes of stress-related biomarkers. Study quality was assessed using ROBINS-E, and a random-effects meta-analysis estimated the overall effect size. RESULTS: Five studies met the inclusion criteria. Four reported significant associations between discrimination, particularly everyday or adolescent exposure, and higher AL. One study found a negative association moderated by coping mechanisms, while another revealed a significant interaction with hopefulness. Meta-analysis of four studies showed a small, non-significant pooled effect (Hedges's g = 0.132; 95 % CI: -0.338-0.602; p = 0.582) with high heterogeneity (I² = 94.24 %). Stronger associations appeared in studies using broader biomarker panels and more recent discrimination measures. CONCLUSIONS: This study highlights an inconsistent and heterogeneous relationship between discrimination and AL in Black middle-aged and older adults. While evidence suggests a general link, findings remain mixed due to methodological variability. The meta-analysis found no significant pooled effect, reflecting limited and diverse studies. Future research should prioritize longitudinal designs, standardized measures, and consideration of coping and resilience factors.