Asian Indian Phenotype

Asian Indian Phenotype (Thin-Fat Asian Indian)

  • At any body mass index (BMI) and age, Asian Indians have higher body fat, visceral fat and waist circumference (WC); lower skeletal muscle mass; thinner hips; short legs; profoundly higher rates of insulin resistance, metabolic syndrome, diabetes, dyslipidemia hypoadiponectinemia, and increased cardiovascular risk than Europids.1-8 These unique clinical and biochemical characteristics that are  commonly found  among Asian Indians in particular and South Asians in general are collectively referred to as the “Asian Indian Phenotype” or  thin –fat phenotype.9 (Figure 052)

  • The Asian Indian phenotype fit into the model of metabolically obese, normal weight individuals.10  This group comprises only 6% of all whites but the overwhelming majority of South Asians.6, 11
  • At comparable levels of total body fat, intra abdominal fat and subcutaneous abdominal fat, Asian Indians have significantly larger adipocytes compared to Europids and is correlated with insulin resistance and adiponectin levels.12
  • The proclivity for increased visceral fat and insulin resistance is evident even among children aged 8 to 11 years.3, 13, 14  For example, South Asian children with a WC of 80 cm have higher insulin levels than white children with a WC of 90 cm.14
  • In addition, South Asians also have significant procoagulant tendencies as shown by high plasminogen activator inhibitor-1 and fibrinogen concentrations.15-17  These metabolic abnormalities also contribute to the increased predilection to diabetes and CAD.9
  • Presence of excess dorsocervical fat (buffalo hump) and excess fat deposit under the chin (double chin) may be used as novel phenotypic markers for insulin resistance and metabolic syndrome among Asian Indians.18, 19
  • Truncal subcutaneous adiposity measured by subscapular and suprailiac skin fold thickness is more in Asian Indians and correlates with insulin resistant metabolic syndrome.5, 20, 21
  • Phenotypic differences in obesity and body composition between South Asians and whites are in part responsible for greater metabolic perturbations in the former and have great implications for pathophysiology, management and prevention of obesity–related diseases.3, 5, 13, 14, 22, 23
  • Sniderman et al24 have proposed the adipose tissue overflow hypothesis to explain the predilection for abdominal obesity, metabolic syndrome and diabetes among South Asians. According to this hypothesis, Asian Indians have very small primary fat depot (the metabolically inert superficial subcutaneous adipose tissue compartment in the lower extremities) compared to Europids.
  • When energy excess induces obesity, Asian Indians and South Asians rapidly exhaust the storage capacity of their superficial subcutaneous adipose tissue compartment and accumulate fat in the deep subcutaneous tissue and especially the visceral fat depots, before whites do. These secondary adipose tissue compartments are characterized by higher transmembrane fatty acid fluxes resulting in high incidence of dysglycemia, atherogenic dyslipidemia and their product—accelerated vascular disease. 24
  • This adipose tissue overflow explains the greater cardiometabolic risk in South Asians than in white people at the same absolute adipose tissue body mass.24, 25
  • Many Asian Indians develop metabolic syndrome and diabetes at BMI <25 kg/m2, which is generally considered normal among whites.9, 26 This also explains why BMI may underestimate the cardiometabolic risk which may be best evaluated by WC or waist-hip ratio.3, 27

Sources 

1. Sharp PS, Mohan V, Levy JC, Mather HM, Kohner EM. Insulin resistance in patients of Asian Indian and European origin with non-insulin dependent diabetes. Hormone and metabolic research. Hormon- und Stoffwechselforschung. Feb 1987;19(2):84-85.

2. Deepa R, Sandeep S, Mohan V. Abdominal obesity, viceral fat, and type 2 diabetes- “Asian Indian Phenotype”. In: Mohan V, Gundu Rao, eds. Type 2 diabetes in South Asians; Epidemiology , Risk factors and Prevention. New Delhi: Jaypee Medical Publishers; 2006:138-152.

3. Raji A, Seely EW, Arky RA, Simonson DC. Body fat distribution and insulin resistance in healthy Asian Indians and Caucasians. The Journal of clinical endocrinology and metabolism. 2001;86(11):5366-5371.

4. Yajnik CS, Fall CH, Coyaji KJ, et al. Neonatal anthropometry: the thin-fat Indian baby. The Pune Maternal Nutrition Study. Int J Obes Relat Metab Disord. Feb 2003;27(2):173-180.

5. Kamath SK, Hussain EA, Amin D, et al. Cardiovascular disease risk factors in 2 distinct ethnic groups: Indian and Pakistani compared with American premenopausal women. Am J Clin Nutr. 1999;69(4):621-631.

6. Banerji MA, Faridi N, Atluri R, Chaiken RL, Lebovitz HE. Body composition, visceral fat, leptin, and insulin resistance in Asian Indian men. The Journal of clinical endocrinology and metabolism. 1999;84(1):137-144.

7. Rush E. C., Freitas I, Plank LD. Body size, body composition and fat distribution: comparative analysis of European, Maori, Pacific Island and Asian Indian adults. The British journal of nutrition. Aug 2009;102(4):632-641.

8. Unni U. S., Ramakrishnan G, Raj T, et al. Muscle mass and functional correlates of insulin sensitivity in lean young Indian men. European journal of clinical nutrition. Oct 2009;63(10):1206-1212.

9. 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.

10. Ruderman N, Chisholm D, Pi-Sunyer X, Schneider S. The metabolically obese, normal-weight individual revisited. Diabetes. 1998;47(5):699-713.

11. Huffman M D, Prabhakaran D, Osmond C, et al. Incidence of cardiovascular risk factors in an Indian urban cohort results from the new delhi birth cohort. J Am Coll Cardiol. Apr 26 2011;57(17):1765-1774.

12. Chandalia M, Lin P, Seenivasan T, et al. Insulin resistance and body fat distribution in South Asian men compared to Caucasian men. PLoS ONE. 2007;2(8):e812.

13. Chandalia M, Abate N, Garg A, Stray-Gundersen J, Grundy SM. Relationship between generalized and upper body obesity to insulin resistance in Asian Indian men. The Journal of clinical endocrinology and metabolism. 1999;84(7):2329-2335.

14. Whincup PH, Gilg JA, Papacosta O, et al. Early evidence of ethnic differences in cardiovascular risk: cross sectional comparison of British South Asian and white children. Bmj. 2002;324(7338):635.

15. Hughes K, Aw TC, Kuperan P, Choo M. Central obesity, insulin resistance, syndrome X, lipoprotein(a), and cardiovascular risk in Indians, Malays, and Chinese in Singapore. J Epidemiol Community Health. 1997;51(4):394-399.

16. Kain K, Blaxill JM, Catto AJ, Grant PJ, Carter AM. Increased fibrinogen levels among South Asians versus Whites in the United Kingdom are not explained by common polymorphisms. Am J Epidemiol. 2002;156(2):174-179.

17. Anand SS, Yusuf S, Vuksan V, et al. Differences in risk factors, atherosclerosis, and cardiovascular disease between ethnic groups in Canada: the Study of Health Assessment and Risk in Ethnic groups (SHARE). Lancet. 2000;356(9226):279-284.

18. Misra A., Jaiswal A, Shakti D, et al. Novel phenotypic markers and screening score for the metabolic syndrome in adult Asian Indians. Diabetes Res Clin Pract. Feb 2008;79(2):e1-5.

19. Cheung O., Kapoor A, Puri P, et al. The impact of fat distribution on the severity of nonalcoholic fatty liver disease and metabolic syndrome. Hepatology (Baltimore, Md. Oct 2007;46(4):1091-1100.

20. Peters J., Ulijaszek SJ. Population and sex differences in arm circumference and skinfold thicknesses among Indo-Pakistani children living in the East Midlands of Britain. Ann Hum Biol. Jan-Feb 1992;19(1):17-22.

21. Goel K, Misra A, Vikram NK, Poddar P, Gupta N. Subcutaneous abdominal adipose tissue is associated with the metabolic syndrome in Asian Indians independent of intra-abdominal and total body fat. Heart. Apr 2010;96(8):579-583.

22. Misra A., Vikram NK. Clinical and pathophysiological consequences of abdominal adiposity and abdominal adipose tissue depots. Nutrition (Burbank, Los Angeles County, Calif. May 2003;19(5):457-466.

23. Misra A. Overnutrition and nutritional deficiency contribute to metabolic syndrome and atherosclerosis in Asian Indians. Nutrition (Burbank, Los Angeles County, Calif. 2002;18(7-8):702-703.

24. Sniderman AD, Bhopal R, Prabhakaran D, Sarrafzadegan N, Tchernof A. Why might South Asians be so susceptible to central obesity and its atherogenic consequences? The adipose tissue overflow hypothesis. Int J Epidemiol. Feb 2007;36(1):220-225.

25. Gealekman O., Guseva N, Hartigan C, et al. Depot-specific differences and insufficient subcutaneous adipose tissue angiogenesis in human obesity. Circulation. Jan 18 2011;123(2):186-194.

26. 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.

27. Reddy KS, Satija A. The Framingham Heart Study: impact on the prevention and control of cardiovascular diseases in India. Prog Cardiovasc Dis. Jul-Aug 2010;53(1):21-27.

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