Low socioeconomic status (SES) is associated with poor health outcomes in patients who have coronary heart disease (CHD). Inflammation is a potential mechanism by which low SES may lead to adverse cardiovascular outcomes, but it is not known whether low SES is associated with inflammation in patients who have CHD. We measured high-sensitivity C-reactive protein (CRP) levels in a cross-sectional study of 985 adults who had CHD. Income and education were determined by self-report. We used ordinal logistic regression to examine the association of income and education with CRP. Of the 985 participants, 390 had high CRP levels (>3 mg/dl). The proportion of participants who had high CRP levels ranged from 30% (103 of 340) in those who had a college degree to 51% (65 of 127) in those who had less than a high school degree (p <0.0001). The proportion of subjects who had a high CRP level ranged from 28% (52 of 183) in those who had annual income >$50,000 to 42% (199 of 974) in those who had an annual income <$20,000 (p <0.001). After adjustment for traditional cardiovascular risk factors and other potential confounding variables, lower income and education remained associated with higher CRP levels. In conclusion, low SES is associated with high CRP levels in patients who have CHD. This observation raises the possibility that inflammation may contribute to the adverse cardiovascular outcomes associated with low SES.To determine the relation between socioeconomic status (SES) and level of C-reactive protein (CRP), we assessed income and education and measured CRP in a cross-sectional study of 985 adults who had coronary heart disease (CHD). We hypothesized that lower income and education would be associated with higher CRP levels after adjusting for demographic characteristics, traditional CHD risk factors, medical co-morbidities, medication use, and other clinical indicators.
Methods
ParticipantsThe Heart and Soul Study is a prospective cohort study that examines the influence of psychosocial factors on health outcomes in patients who have coronary artery disease. Methods have been described previously. A total of 15,438 eligible patients was mailed an invitation to participate, and 2,495 responded that they would be interested. Of the 2,495 patients whom we attempted to contact by telephone to schedule a study appointment, 505 could not be reached and 596 declined to participate. An additional 370 patients were excluded because they had a history of myocardial infarction in the previous 6 months, deemed themselves unable to walk 1 block, or were planning to move out of the local area within 3 years.Between September 2000 and December 2002, 1,024 participants enrolled and attended a daylong appointment at the Veterans Affairs Medical Center in San Francisco. For this crosssectional study, we excluded 39 subjects from whom we could not obtain serum samples, leaving 985 participants for analysis. This study protocol was approved by the appropriate institutional review boards, and all participants provided written, ...