Diabetes and Obesity
- Obesity is perhaps the foremost risk factor for diabetes with a prevalence of just 3% for whites with normal weight, body mass index (BMI) < 25 kg/m2, but higher for the minority ethnic groups.
- For the same BMI, the prevalence of diabetes was 3 times higher among all nonwhite ethnic groups in the US.1 The risk of diabetes among Asian Indian with a BMI of 24 is similar to that of a white with BMI of 30 in Canada (Figure 088).2 This underscores the need to use lower cut points for obesity in South Asians.3 South Asians also develop diabetes at a younger age (age 49) compared to Chinese (age 55) blacks (age 57) and whites (age 58) .2
- Among older adults, total and central adiposity, and weight gain during middle age and after the age of 65 years are associated with risk of diabetes. Persons who gained 9 kilograms or more after 50 years of age had an approximate 3-fold greater risk for developing diabetes. The so called normal weight gain seen in the middle age is not really normal and there is a heavy price to pay in the form of diabetes.
- Asian Indians have an increased genetic susceptibility to deposit visceral fat, which is metabolically active and strongly related to insulin resistance. This so called western style of living consisting of excess caloric energy consumption and reduced energy expenditure is no longer limited to western countries but it is fast becoming a universal phenomenon seen with increasing frequency in low and middle income countries. Migration and urbanization often lead to dietary changes with higher intakes of sugars, animal fats, and vegetable oils.
- The generalized and central obesity levels at which diabetes occurs is also lower in Indian subjects compared to the white populations. The risk of diabetes increases steeply with BMI >23 in South Indians and 60% of them have BMI in this range.4, 5
- Waist-circumference (WC) is a better predictor of diabetes than BMI.6 For South Asians, a waist size of ≥90 cm in men and ≥80 cm in women is now accepted as a major risk factor for diabetes, metabolic syndrome, and other cardiovascular risk factors.7, 8
- Abnormal pattern of body fat distribution is present at birth or soon after among Asian Indians.9 10 Poor gestational nutrition may contribute to the development of metabolic abnormalities, leading to diabetes and coronary artery disease (CAD) later in life.11, 12 The increased risk of gestational diabetes, combined with exposure to poor nutrition in utero and overnutrition in later life may contribute to the increasing diabetes epidemic through “diabetes begetting diabetes.” 13
- Indians are susceptible to diabetes at a younger age and at a relatively lower BMI compared to the white Caucasians. This is partly explained by the fact that the thin-looking Indians are quite adipose (higher body fat percent). Intrauterine epigenetic regulation could explain the thin-fat Indian body composition (see Asian Indian Phenotype).14
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2. Chiu M, Austin PC, Manuel DG, Shah BR, Tu JV. Deriving ethnic-specific BMI cutoff points for assessing diabetes risk. Diabetes Care. Aug 2011;34(8):1741-1748.
3. WHO/IASO/ITO. Asia Pacific Perspective:Redefing obesity and its treatment World Health Organization, Western Pacific Region;2000.
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5. Mohan V, Deepa M, Farooq S, Prabhakaran D, Reddy KS. Surveillance for risk factors of cardiovascular disease among an industrial population in southern India. Natl Med J India. Jan-Feb 2008;21(1):8-13.
6. Ajay VS, Prabhakaran D, Jeemon P, et al. Prevalence and determinants of diabetes mellitus in the Indian industrial population. Diabet Med. Oct 2008;25(10):1187-1194.
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8. 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.
9. Krishnaveni GV, Hill JC, Veena SR, et al. Truncal adiposity is present at birth and in early childhood in South Indian children. Indian Pediatr. Jun 2005;42(6):527-538.
10. Ehtisham S, Crabtree N, Clark P, Shaw N, Barrett T. Ethnic differences in insulin resistance and body composition in United Kingdom adolescents. J Clin Endocrinol Metab. Jul 2005;90(7):3963-3969.
11. 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.
12. Godfrey KM, Barker DJ. Fetal nutrition and adult disease. Am J Clin Nutr. 2000;71(5 Suppl):1344S-1352S.
13. Chan JC, Malik V, Jia W, et al. Diabetes in Asia: epidemiology, risk factors, and pathophysiology. JAMA. May 27 2009;301(20):2129-2140.
14. Yajnik CS, Ganpule-Rao AV. The obesity-diabetes association: what is different in indians? Int J Low Extrem Wounds. Sep 2010;9(3):113-115.