Asian Indian Paradox
- Asian Indian paradox refers to the excess burden of heart disease among Asian Indians despite having a low prevalence of traditional risk factors. Studies in the US, UK, Canada, Singapore, and other countries have shown prevalence of traditional risk factors such as smoking, obesity, hypertension, and high cholesterol levels is similar or lower in Asian Indians compared to Europids.1
- The prevalence of traditional risk factors, however, is high and increasing in India in sharp contrast to those observed in the Indian Diasporas.2
- Coronary artery disease (CAD) rates and lipoprotein levels are similar among vegetarians and non-vegetarians. This is in sharp contrast to the findings from Western vegetarians, who have a favorable lipid profile and low rates of CAD.3 4
- Although the prevalence of insulin resistance, glucose intolerance, metabolic syndrome, and diabetes are very high, these conditions do not fully explain the excess burden of premature death from CAD among Asian Indians.5 Prospective studies have shown that the incidence and mortality from CAD is at least two-fold higher among Asian Indians, even when adjusted for standard risk factors including diabetes and metabolic syndrome.5, 6
- Asian Indian physicians in the US have a 4-fold higher prevalence of CAD compared to American population.3 This high rate is in sharp contrast to the 4-fold lower rate of CAD among American physicians who participated in the Physicians’ Health Study.3
- The Coronary Artery Disease in Indians (CADI) Study has demonstrated a similar or lower prevalence of all major conventional risk factors, except for diabetes. Physical activity was high (136 minutes /week) and saturated fat consumption was low (8% of the daily energy intake). The high rate of CAD among Asian Indians despite these enviable levels of risk factors suggest an important role of a genetic risk factor, unrelated to, and possibly not amenable to even the maximum modification of lifestyle.7
- Risk prediction models using standard risk factors, while accurate in whites, overestimate the risk in Chinese and underestimate the risk in Asian Indians by 140%-220%8-10 Specific recommendations have been made to compensate for the underestimation of risk in this population.11-13
- Although the conventional risk factors do not fully explain the excess burden of CAD, these risk factors appear to be doubly important in Asian Indians and remain the principal targets for prevention and treatment. More importantly, the threshold of intervention and treatment targets should be lower in Asian Indians by 10% to 20%.12, 14
Sources
1. Enas EA. Why Indians are more susceptible to Coronary artery disease: Role of specific risk factors In: Chatterjee SS, ed. Update in Cardiology Hyderabad: Cardiology Society of India; 2007.
2. Reddy KS, Prabhakaran D, Chaturvedi V, et al. Methods for establishing a surveillance system for cardiovascular diseases in Indian industrial populations. Bull World Health Organ. Jun 2006;84(6):461-469.
3. Enas EA, Garg A, Davidson MA, Nair VM, Huet BA, Yusuf S. Coronary heart disease and its risk factors in first-generation immigrant Asian Indians to the United States of America. Indian heart journal. Jul-Aug 1996;48(4):343-353.
4. Chuang CZ, Subramaniam PN, LeGardeur BY, Lopez A. Risk factors for coronary artery disease and levels of lipoprotein(a) and fat-soluble antioxidant vitamins in Asian Indians of USA. Indian heart journal. 1998;50(3):285-291.
5. Forouhi NG, Sattar N, Tillin T, McKeigue PM, Chaturvedi N. Do known risk factors explain the higher coronary heart disease mortality in South Asian compared with European men? Prospective follow-up of the Southall and Brent studies, UK. Diabetologia. Nov 2006;49(11):2580-2588.
6. Yagalla MV, Hoerr SL, Song WO, Enas E, Garg A. Relationship of diet, abdominal obesity, and physical activity to plasma lipoprotein levels in Asian Indian physicians residing in the United States. J Am Diet Assoc. 1996;96(3):257-261.
7. Enas EA. High rates of CAD in Asian Indians in the United States despite intense modification of lifestyle: What next? Current Science. 1998;74:1081-1086.
8. Lip GY, Barnett AH, Bradbury A, et al. Ethnicity and cardiovascular disease prevention in the United Kingdom: a practical approach to management. J Hum Hypertens. Mar 2007;21(3):183-211.
9. Cappuccio FP, Oakeshott P, Strazzullo P, Kerry SM. Application of Framingham risk estimates to ethnic minorities in United Kingdom and implications for primary prevention of heart disease in general practice: cross sectional population based study. Bmj. 2002;325(7375):1271.
10. D’Agostino RB Sr, Grundy S, Sullivan LM, Wilson P. Validation of the Framingham coronary heart disease prediction scores: results of a multiple ethnic groups investigation. Jama. 2001;286(2):180-187.
11. Misra A , Chowbey P, Makkar B. Consensus statement for diagnosis of obesity, abdominal obesity, and metabolic syndrome, for Asian Indians and recomendations for physical activity, medical and surgical management. JAPI. 2009;57:163-170.
12. Enas EA, Singh V, Gupta R, Patel R, et al. Recommendations of the Second Indo-US Health Summit for the prevention and control of cardiovascular disease among Asian Indians. Indian heart journal. 2009;61:265-74.
13. Graham I, Atar D, Borch-Johnsen K, Boysen G, Durrington PN. European guidelines on cardiovascular disease prevention in clinical practice: executive summary: Fourth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (Constituted by representatives of nine societies and by invited experts). Eur Heart J. Oct 2007;28(19):2375-2414.
14. Enas EA. How to Beat the Heart Disease Epidemic among South Asians: A Prevention and Management Guide for Asian Indians and their Doctors. Downers Grove: Advanced Heart Lipid Clinic USA; 2007.