The prospective association of socioeconomic status with C-reactive protein levels in the CARDIA study

Better health is a well-documented benefit of having a higher socioeconomic status (SES). Inflammation may be one pathway through which SES influences health. Using 2658 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, we examine whether two measures of SES assessed at baseline (mean age, 32 ± 4 years)—years of education and household income—predict change in C-reactive protein (CRP) concentrations over the course of 13 years. We also examine whether four health-related behaviors—smoking, fruit and vegetable consumption, physical activity, and alcohol consumption—mediate the prospective association of SES with CRP. Both higher education and household income predicted smaller increases in CRP over the 13 years of follow-up independent of age, sex, race, CARDIA center, body mass, medical diagnoses, medications, and hormone use (among women). Associations did not differ by race or sex. When examined in separate analyses, smoking and fruit and vegetable intake each accounted for a significant proportion of the respective effects of education and household income on CRP change, and physical activity a significant proportion of the effect of household income. These findings suggest that poor health behaviors among persons of lower socioeconomic status can have long-term effects on inflammation.