Differences in educational attainment mediate race differences in inflammation among older adults

Background: C-reactive protein (CRP) is a measure of systemic inflammation that is associated with cardiovascular diseases. Race and ethnic differences in levels of CRP exist and may be explained by corresponding differences in socioeconomic status. The current study aims to determine whether race differences in CRP exist among older adults, and whether these differences are mediated by differences in educational attainment.

Methods: Using data from the Health and Retirement Study (HRS), linear regression was used to estimate differences in CRP by race/ethnicity. Regression modeling was followed by a formal test of the mediating effect of educational attainment. Analyses used sampling weights to account for the complex sample design of the HRS and addressed missing data using multiple imputation. The sample included 12,102 adults aged 52 years and older.

Results: Blacks and Hispanics have lower levels of educational attainment than non-Hispanic whites, but higher levels of inflammation in unadjusted models (blacks: B=0.35, SE=0.05; Hispanics: B=0.16, SE=0.04). After adjusting for relevant covariates, race and ethnic differences in CRP were attenuated; only differences between blacks and whites remained significant (blacks: B=0.20, SE=0.05; Hispanics: B=-0.03, SE=0.05). Differences in educational attainment accounted for approximately14% of the net difference in inflammation between blacks and non-Hispanic whites (p<0.001), and 50% of the difference between Hispanics and non-Hispanic whites (p<0.001).

Discussion: Differences in educational attainment only partially explain race/ethnic differences in CRP among older adults. Future research should seek to elaborate the mechanisms leading to greater levels of inflammation and identify additional factors explaining group difference in CRP.