Racial Differences in Elevated C-Reactive Protein Among US Older Adults

OBJECTIVES To investigate racial differences in elevated C-reactive protein (CRP) and the potential factors contributing to these differences in US older men and women. DESIGN Nationally representative cohort study. SETTING Health and Retirement Study, 2006 to 2014. PARTICIPANTS Noninstitutionalized non-Hispanic black and white older adults living in the United States (n = 13 517). MEASUREMENTS CRP was categorized as elevated (>3.0 mg/L) and nonelevated (<= 3.0 mg/L) as the primary outcome. Measures for demographic background, socioeconomic status, psychosocial factors, health behaviors, and physiological health were examined as potential factors contributing to race differences in elevated CRP. RESULTS Median CRP levels (interquartile range) were 1.67 (3.03) mg/L in whites and 2.62 (4.95) mg/L in blacks. Results from random effects logistic regression models showed that blacks had significantly greater odds of elevated CRP than whites (odds ratio = 2.58; 95% confidence interval [CI] = 2.20-3.02). Results also showed that racial difference in elevated CRP varied significantly by sex (predicted probability [PP] [white men] = 0.28 [95% CI = 0.27-0.30]; PP [black men] = 0.38 [95% CI = 0.35-0.41]; PP [white women] = 0.35 [95% CI = 0.34-0.36]; PP [black women] = 0.49 [95% CI = 0.47-0.52]) and remained significant after risk adjustment. In men, the racial differences in elevated CRP were attributable to a combination of socioeconomic (12.3%) and behavioral (16.5%) factors. In women, the racial differences in elevated CRP were primarily attributable to physiological factors (40.0%). CONCLUSION In the US older adult population, blacks were significantly more likely to have elevated CRP than whites; and the factors contributing to these differences varied in men and women.