UCLA

Previous studies demonstrated that blacks have less coronary artery calcification (CAC) than whites. We evaluated racial differences in plaque composition and stenosis in the Multicenter AIDS Cohort Study. HIV-positive and HIV-negative men underwent noncontrast cardiac computed tomography (CT) if they were aged 40 to 70 years, weighed <136 kg, and had no history of cardiac surgery or revascularization and, if eligible, coronary CT angiography (CTA). There were 1,001 men who underwent CT scans and 759 men CTA. We measured CAC on noncontrast CT and identified total plaque, noncalcified plaque, calcified plaque, mixed plaque, and coronary stenosis >50% on CTA. The association of presence and extent of plaque with race was determined after adjustment for HIV serostatus, cardiovascular risk factors, and measures of socioeconomic status. The prevalences of any plaque on CTA and noncalcified plaque were not different between black and white men; however, black men had lower prevalences of CAC (prevalence ratio [PR] 0.79, p = 0.01), calcified plaque (PR 0.69, p = 0.002), and stenosis >50% (PR 0.59, p = 0.009). There were no associations between black race and extent of plaque in fully adjusted models. Using log-linear regression, black race was associated with a lower extent of any plaque on CTA in HIV-positive men (estimate = -0.24, p = 0.051) but not in HIV-negative men (0.12, p = 0.50, HIV interaction p = 0.005). In conclusion, a lower prevalence of CAC in black compared with white men appears to reflect less calcification of plaque and stenosis rather than a lower overall prevalence of plaque.