It is unclear to what extent the apparently beneficial cardiovascular effects of moderate alcohol consumption are mediated by protection against atherosclerosis. Alcohol consumption, coronary heart disease risk factors, and coronary calcification (a marker of atherosclerosis) were measured during 15 years of follow-up in the Coronary Artery Risk Development in Young Adults (CARDIA) Study (1985-2001). Among 3,037 participants aged 33-45 years after follow-up (55% women, 45% Black), the prevalence of coronary calcification was 8% for consumption of 0 drinks/week (n = 1,435), 9% for 1-6 drinks/week (n = 1,023), 13% for 7-13 drinks/week (n = 341), and 19% for ≥14 drinks/week (n = 238) (p < 0.001 for trend). Calcification was also more common among binge drinkers (odds ratio = 2.1, 95% confidence interval: 1.6, 2.7). These associations persisted after adjustment for potential confounders (age, gender/ethnicity, income, physical activity, family history, body mass index, smoking) and intermediary factors (lipids, blood pressure, glucose, C-reactive protein, and fibrinogen). Stratification showed the dose-response relation most clearly in Black men; only heavier alcohol consumption (≥14 drinks/week) was associated with coronary calcification in other race/sex subgroups. These surprising findings suggest the presence of proatherogenic effects of alcohol in young adults, especially Black men, which may counterbalance high density lipoprotein cholesterol elevation and other possible benefits of alcohol consumption. Copyright © 2005 by the Johns Hopkins Bloomberg School of Public Health All rights reserved.