Metabolic Syndrome in South Asians
- South Asians represent one of the largest and fastest growing ethnic groups in the world and they are experiencing the twin epidemics of coronary artery disease (CAD) and diabetes.1The metabolic syndrome (MS) is a crucial factor in the development of diabetes and CAD and is found in 20-50% of South Asians depending upon the criteria used.2, 3
- In the UK, South Asians have the highest prevalence of the MS and diabetes─more than double the rates in whites using NCEP definition (30% vs 14%).4 The risk of CAD among South Asians with MS is also higher than that of whites (2.1 vs 1.6).4 In sharp contrast, the association of MS with CAD is weaker in African-Caribbeans.4
- The prevalence of MS was 21% based on IDF criteria and 23% according to the NCEP definition in Nepal.5 Both IDF and NCEP criteria underestimate the prevalence of MS by 25-50%.6
- Atherogenic dyslipidemia, glucose intolerance, thrombotic tendency, subclinical inflammation, and endothelial dysfunction are higher in South Asians with MS than Caucasians. Many of these manifestations are more severe and are seen at an early age (including childhood) in South Asians than Caucasians.3 MS is also seen in people living in slums and rural areas.
- The main drivers include dietary westernization, poor lifestyle measures, and socioeconomic transitions, consequent to increasing affluence, urbanization, mechanization, and rural-to-urban migration.3 Cardiovascular disease (CVD) risk in South Asians is also heightened by their higher body fat, especially intra-abdominal fat, and ectopic fat deposition (liver fat, pancreas etc.). Further, CVD risk cluster manifests at a lower level of adiposity and abdominal obesity.3
- The controversy about the definition of MS has been resolved and there is now a single global definition with specific lower cutpoints for waist circumference for Asian Indians and other Asians so that physicians could intervene early with lifestyle management.3, 7 See Metabolic Syndrome Criteria. Health care practitioners must be aware that Europid cutpoints used to identify individuals with MS would substantially underestimate the burden of South Asians. 1
- It is particularly important to effectively implement and strengthen population-based primary prevention strategies for the prevention of ‘epidemic’ of obesity and MS. The lifestyle factor modification to prevent the MS and diabetes in South Asians should start in early childhood. 2
Sources
1. Eapen D, Kalra GL, Merchant N, Arora A, Khan BV. Metabolic syndrome and cardiovascular disease in South Asians. Vasc Health Risk Manag. 2009;5:731-743.
2. Misra A, Misra R, Wijesuriya M, Banerjee D. The metabolic syndrome in South Asians: continuing escalation & possible solutions. Indian J Med Res. Mar 2007;125(3):345-354.
3. Misra A, Khurana L. The metabolic syndrome in South Asians: epidemiology, determinants, and prevention. Metab Syndr Relat Disord. Dec 2009;7(6):497-514.
4. Tillin T, Forouhi N, Johnston DG, McKeigue PM, Chaturvedi N, Godsland IF. Metabolic syndrome and coronary heart disease in South Asians, African-Caribbeans and white Europeans: a UK population-based cross-sectional study. Diabetologia. Apr 2005;48(4):649-656.
5. Sharma SK, Ghimire A, Radhakrishnan J, et al. Prevalence of hypertension, obesity, diabetes, and metabolic syndrome in Nepal. Int J Hypertens. 2011;2011:821971.
6. Enas EA, Mohan V, Deepa M, Farooq S, Pazhoor S, Chennikkara H. The metabolic syndrome and dyslipidemia among Asian Indians: a population with high rates of diabetes and premature coronary artery disease. Journal of the cardiometabolic syndrome. Fall 2007;2(4):267-275.
7. Alberti KG, Eckel RH, Grundy SM, et al. Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and international association for the Study of Obesity. Circulation. Oct 20 2009;120(16):1640-1645.