Twin Epidemic

Twin Epidemics of Heart Disease and Diabetes among South Asians 

  • South Asian population has the highest risk of developing diabetes and premature heart disease.1-4 South Asians account for 20% of the world’s population but would contribute to 40% of the cardiovascular diseases (CVD) burden by 2020.3 Coronary artery disease (CAD) rates are 50% to 400% higher among Indian Diasporas compared to Chinese, Whites and Blacks and other populations with greater risk at younger ages.5
  • The prevalence of diabetes is conservatively estimated to be 12-18% % in urban India and will continue to rise with increasing obesity and urbanization.6 Diabetes prevalence rates among Indian Diasporas are 2 to 6-fold higher than those of age and sex-matched Europid adults.7, 8 Over 20% of middle aged and elderly South Asian people throughout the world have diabetes.9 South Asian adults with diabetes show a markedly increased predisposition to CVD compared with Europids, especially in younger people.9 The complications of both diabetes and CVD are greater among South Asians than whites and is associated with very high and premature mortality.3 10
  • INTERHEART and other studies have shown that both conditions develop at a younger age (about 5-10 years earlier) and at lower body mass index (BMI) and waist circumference (WC) among South Asians than Europids.3, 10 Importantly, diabetes is diagnosed 10 years earlier in South Asians, at a mean age of 46 years, compared with 57 years in Europids, and at a lower BMI.11 The mean age of occurrence of first heart attack is 53 years in South Asians, compared with 59 years in other populations.10
  • Insulin resistance and related arthrosclerosis risk factors are highly prevalent, and develop at much lower levels of BMI and WC.3 Conventional risk factors such as dyslipidemia and smoking are equally prevalent but perhaps more potent. Novel risk factors such lipoprotein(a) are more common among South Asians and are highly correlated with premature heart attack and stroke in this population.3, 12, 13
  • As a result of advanced treatment, diabetics rarely die from high blood sugar. Instead, CVD accounts for 65%-80% of all deaths among diabetics. Men with diabetes have a 2-3 fold higher risk of dying from heart attack, whereas women have a 4-6 fold high risk. Compared to white diabetics, South Asian diabetics have a 2-3 fold higher risk of dying from a heart attack. 14 
  • Emerging evidence suggests that both of these deadly diseases are the results of complex interplay of genetic susceptibility and environmental factors. Both diabetes and heart disease share the same precursors and are believed to spring from a common soil.15 These precursors or principal drivers include insulin resistance, abdominal obesity, atherogenic diet (high in calories and saturated fat and/or trans fat, low in fruits and vegetables), physical inactivity, and tobacco use.15-17
  • Lifestyle changes associated with affluence, urbanization, and mechanization are seen in South Asians transitioning from rural to urban communities in India, as well as in South Asian Diasporas in developed countries such as Canada, US and UK.8 18-20 A higher prevalence of some high-risk alleles have been reported in South Asians.21
  • Ironically, factors related to South Asian culture including diet, lifestyle and health beliefs have a significant impact on this risk of developing diabetes and CVD.22 Clinicians looking after South Asian people should be made aware of the existence of new ethnic specific criteria for screening BMI, WC, and metabolic syndrome and the need for aggressive management of conventional risk factors.3 

Sources

1.  Ali MK, Narayan KM, Mohan V. Innovative research for equitable diabetes care in India. Diabetes Res Clin Pract. Dec 2009;86(3):155-167.

2. Mohan V, Sandeep S, Deepa R, Shah B, Varghese C. Epidemiology of type 2 diabetes: Indian scenario. Indian J Med Res. Mar 2007;125(3):217-230.

3. Gholap N, Davies M, Patel K, Sattar N, Khunti K. Type 2 diabetes and cardiovascular disease in South Asians. Prim Care Diabetes. Sep 23 2010.

4. Gupta R, Joshi P, Mohan V, Reddy KS, Yusuf S. Epidemiology and causation of coronary heart disease and stroke in India. Heart (British Cardiac Society). Jan 2008;94(1):16-26.

5. Balarajan R. Ethnic differences in mortality from ischaemic heart disease and cerebrovascular disease in England and Wales. Bmj. Mar 9 1991;302(6776):560-564.

6. Ramachandran A, Mary S, Yamuna A, Murugesan N, Snehalatha C. High prevalence of diabetes and cardiovascular risk factors associated with urbanization in India. Diabetes Care. May 2008;31(5):893-898.

7. Balakrishnan R, Webster P, Sinclair D. Trends in overweight and obesity among 5-7-year-old White and South Asian children born between 1991 and 1999. J Public Health (Oxf). Jun 2008;30(2):139-144.

8. Lau DCW. Excess Prevalence and Mortality Rates of Diabetes and Cardiovascular Disease Among South Asians:A Call to Action. Canadian Journal of Diabetes. 2010(June 20):102-104.

9. Mather HM, Chaturvedi N, Fuller JH. Mortality and morbidity from diabetes in South Asians and Europeans: 11- year follow-up of the Southall Diabetes Survey, London, UK. Diabet Med. 1998;15(1):53-59.

10. Joshi P, Islam S, Pais P, et al. Risk factors for early myocardial infarction in South Asians compared with individuals in other countries. Jama. Jan 17 2007;297(3):286-294.

11. Mukhopadhyay B, Forouhi NG, Fisher BM, Kesson CM, Sattar N. A comparison of glycaemic and metabolic control over time among South Asian and European patients with Type 2 diabetes: results from follow-up in a routine diabetes clinic. Diabet Med. Jan 2006;23(1):94-98.

12. Gambhir JK, Kaur H, Gambhir DS, Prabhu KM. Lipoprotein(a) as an independent risk factor for coronary artery disease in patients below 40 years of age. Indian heart journal. 2000;52(4):411-415.

13. Christopher R, Kailasanatha KM, Nagaraja D, Tripathi M. Case-control study of serum lipoprotein(a) and apolipoproteins A-I and B in stroke in the young. Acta Neurol Scand. Aug 1996;94(2):127-130.

14. 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.

15. Stern MP. Diabetes and cardiovascular disease: The “common soil” hypothesis. Diabetes. 1995;44(4):369-374.

16. Grundy SM. Does a diagnosis of metabolic syndrome have value in clinical practice? Am J Clin Nutr. Jun 2006;83(6):1248-1251.

17. Yusuf S, Hawken S, Ounpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. Sep 11 2004;364(9438):937-952.

18. Ramachandran A, Snehalatha C, Yamuna A, Murugesan N. High prevalence of cardiometabolic risk factors among young physicians in India. J Assoc Physicians India. Jan 2008;56:17-20.

19. Kuppuswamy VC, Gupta S. Excess coronary heart disease in South Asians in the United Kingdom. Bmj. May 28 2005;330(7502):1223-1224.

20. Owen CG, Nightingale CM, Rudnicka AR, Cook DG, Ekelund U, Whincup PH. Ethnic and gender differences in physical activity levels among 9-10-year-old children of white European, South Asian and African-Caribbean origin: the Child Heart Health Study in England (CHASE Study). Int J Epidemiol. Aug 2009;38(4):1082-1093.

21. Barnett AH, Dixon AN, Bellary S, et al. Type 2 diabetes and cardiovascular risk in the UK south Asian community. Diabetologia. Oct 2006;49(10):2234-2246.

22. Kanaya AM, Wassel CL, Mathur D, et al. Prevalence and correlates of diabetes in South asian indians in the United States: findings from the metabolic syndrome and atherosclerosis in South asians living in america study and the multi-ethnic study of atherosclerosis. Metabolic syndrome and related disorders. Apr 2010;8(2):157-164.

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