The metabolic syndrome and dyslipidemia among Asian Indians: a population with high rates of diabetes and premature coronary artery disease.

South Asians have high rates of diabetes and the highest rates of premature coronary artery disease in the world, both occurring about 10 years earlier than in other populations. The metabolic syndrome (MS), which appears to be the antecedent or "common soil" for both of these conditions, is also common among South Asians. Because South Asians develop metabolic abnormalities at a lower body mass index and waist circumference than other groups, conventional criteria underestimate the prevalence of MS by 25% to 50%. The proposed South Asian Modified National Cholesterol Education Program criteria that use abdominal obesity as an optional component and the South Asian-specific waist circumference recommended by the International Diabetes Federation appear to be more appropriate in this population. Furthermore, Asian Indians have at least double the risk of coronary artery disease than that of whites, even when adjusted for the presence of diabetes and MS. This increased risk appears to be due to South Asian dyslipidemia, which is characterized by high serum levels of apolipoprotein B, lipoprotein (a), and triglycerides and low levels of apolipoprotein A1 and high-density lipoprotein (HDL) cholesterol. In addition, the HDL particles are small, dense, and dysfunctional. MS needs to be recognized as a looming danger to South Asians and treated with aggressive lifestyle modifications beginning in childhood and at a lower threshold than in other populations.

Dyslipidemia in South Asian patients.

South Asians around the globe have the highest rates of coronary artery disease (CAD). These rates are 50% to 300% higher than other populations, with a higher risk at younger ages. These high rates of CAD are accompanied by low or similar rates of major traditional risk factors. The prevalence of diabetes is three to six times higher among South Asians than Europeans, Americans, and other Asians but does not explain the "South Asian Paradox." A genetic predisposition to CAD, mediated by high levels of lipoprotein(a), markedly magnifies the adverse effects of traditional risk factors related to lifestyle and best explains the South Asian Paradox. Although the major modifiable risk factors do not fully explain the excess burden of CAD, they are doubly important and remain the foundation of preventive and therapeutic strategies in this population. A more aggressive approach to preventive therapy, especially dyslipidemia, at an earlier age and at a lower threshold is clearly warranted.