Epidemiology and burden of cardiovascular disease.

Coronary heart disease (CHD) is the leading cause of death in the United States. The rate of CHD and CHD death varies across racial groups, with higher rates among black men and women than among white men and women. The development of CHD is promoted by major CHD risk factors--dyslipidemia, hypertension, and smoking. These risk factors are independently associated with CHD risk and are common among adults in the United States. Diabetes mellitus is also a significant contributor to CHD risk and is associated with risk of a CHD event equivalent to that conferred by the presence of prior CHD. Metabolic syndrome, a related condition, also confers a high risk for CHD as well as for the development of type 2 diabetes. Diabetes and metabolic syndrome are characterized by the presence of central obesity and insulin resistance, which result in dyslipidemia, hypertension, and cardiovascular derangements that promote CHD. Diabetes and metabolic syndrome illustrate the significance of risk factor clustering, which contributes to CHD risk through the additive effect of each risk factor. Diabetes, metabolic syndrome, and risk factor clustering in general are becoming more prevalent, which illustrates the need for better CHD prevention strategies aimed at risk factor control. The pathologic process associated with risk factor clustering also contributes to the higher CHD burden among black men and women, who have a higher prevalence of risk factor clustering and type 2 diabetes. Furthermore, despite having a higher CHD risk, black men and women are less likely to receive adequate treatment or control of risk factors, including dyslipidemia or hypertension. Eliminating disparities among population groups will thus require aggressive efforts focused on risk assessment, guideline adherence, and risk factor control in populations in need.