Major risk factors for coronary heart disease are also associated with early carotid artery thickening, but no studies have yet examined patterns of risk factors to see whether they differ for the two outcomes. Assuming similar pathogenesis for both coronary and carotid atherosclerosis, one could interpret risk factor pattern differences as relating to differences in staging, i.e., early atheroma versus later stenotic or occlusive atherothrombosis. This study included 12,193 Atherosclerosis Risk in Communities Study participants aged 45-64 years who were free of clinical cardiovascular disease in 1987-1989, in whom 420 myocardial infarctions or coronary heart disease deaths occurred over the next 6 years. Plasma low density lipoprotein cholesterol, systolic blood pressure, and smoking were major risk factors for both outcomes. Compared with these factors, triglycerides and high density lipoprotein (HDL) cholesterol were associated only weakly with carotid atherosclerosis but were associated strongly with coronary heart disease incidence. No other risk factors, including those associated with diabetes mellitus, hemostasis, and inflammation, differed in their relative contribution to the two outcomes. These results suggest that the high triglyceride-low HDL cholesterol pattern is involved in the transition from atheroma to atherothrombosis, and that control of this pattern may be important in persons with detectable subclinical disease.