Community socioeconomic status is associated with circulating interleukin-6 and C-reactive protein

To examine the association of both individual and community socioeconomic status (SES) with inflammatory mediators relevant to cardiovascular pathophysiology, i.e., interleukin (IL)-6 and C-reactive protein (CRP), in a midlife community sample. Growing evidence suggests that socioeconomic attributes of both individuals and communities confer risk for cardiovascular morbidity and mortality.

Subjects were 851 men and women, 30 to 54 years of age (Caucasian = 77%, African-American = 23%). Individual SES was indexed by a composite of educational attainment and family income, and community SES was indexed by corresponding indicators derived from US Census data for participants' census tracts of residence. Plasma concentrations of IL-6 and CRP were determined from blood samples.

Regression analyses adjusting for age, sex, and race showed individual SES to be associated inversely with IL-6 (B = -0.126, p < .01), and community SES to be associated inversely with both IL-6 and CRP (B = -0.144, p < .01, B = -0.097, p < .01, respectively). The relationship of community SES with IL-6, but not CRP, persisted on multivariable adjustment for both lifestyle risk factors (smoking, alcohol consumption, sleep, exercise, body mass index) and individual SES (IL-6: B = -0.084, p < .05; CRP: B = -0.047, p > .10). After adjustment for lifestyle factors, however, individual SES was no longer associated with IL-6.

Independent of personal income or educational attainment, midlife adults living in less advantaged neighborhoods exhibit higher levels of circulating proinflammatory markers than residents of more affluent areas. This association may help explain the increased risk of atherosclerotic cardiovascular morbidity and mortality conferred by low community-level SES.