Ethnic variation in fat and lean body mass and the association with insulin resistance

J Clin Endocrinol Metab. 2009 Dec;94(12):4696-702. doi: 10.1210/jc.2009-1030. Epub 2009 Oct 9.

Abstract

Context: Body fat distribution varies among different ethnic groups, yet less is known regarding differences in lean mass and how this may affect insulin resistance.

Objective: Our objective was to compare total body fat to lean mass ratio (F:LM) in Aboriginal, Chinese, European, and South Asian individuals with differences in insulin resistance.

Participants, design, and setting: Aboriginal (196), Chinese (222), European (202), and South Asian (208) individuals were recruited across a range of body mass index to participate in this cross-sectional community study.

Main outcome measures: Total body fat, lean mass, and insulin resistance were assessed using homeostasis model assessment (HOMA).

Results: After adjustment for confounders and at a given body fat, South Asian men had less lean mass than Aboriginal [3.42 kg less; 95% confidence interval (CI) = 1.55-5.29], Chinese (3.01 kg less; 95% CI = 1.33-4.70), and European (3.57 kg less; 95% CI = 1.82-5.33) men, whereas South Asian women had less lean mass than Aboriginal (1.98 kg less; 95% CI = 0.45-3.50), Chinese (2.24 kg less; 95% CI = 0.81-3.68), and European (2.97 kg less; 95% CI = 1.67-4.27) women. In adjusted models, F:LM was higher in South Asian compared with Chinese and European men and higher in South Asian compared with Aboriginal, Chinese, and European women (P < 0.01 for all). Insulin and HOMA were greatest in South Asians after adjustment; however, these differences were no longer apparent when F:LM was considered.

Conclusions: South Asians have a phenotype of high fat mass and low lean mass, which may account for greater levels of insulin and HOMA compared with other ethnic groups.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / physiology*
  • Adult
  • Age Factors
  • Anthropometry
  • Asia, Southeastern / ethnology
  • Asians
  • Body Composition / physiology*
  • Canada
  • China / ethnology
  • Ethnicity*
  • Female
  • Humans
  • Indians, North American
  • Insulin / blood
  • Insulin Resistance / physiology*
  • Life Style
  • Male
  • Middle Aged
  • Regression Analysis
  • Sex Factors
  • Socioeconomic Factors
  • Whites

Substances

  • Insulin