BMI, fat and muscle differences in urban women of five ethnicities from two countries

Int J Obes (Lond). 2007 Aug;31(8):1232-9. doi: 10.1038/sj.ijo.0803576. Epub 2007 Mar 6.


Objective: To investigate body composition differences, especially the relationship between body mass index (BMI) and percent body fat (%BF), among five ethnic groups.

Design: Cross-sectional.

Subjects: Seven hundred and twenty-one apparently healthy women aged 18-60 years (BMI: 17.4-54.0 kg/m(2)) from South Africa (SA, 201 black, 94 European) and New Zealand (NZ, 173 European, 76 Maori, 84 Pacific, 93 Asian Indian).

Measurements: Anthropometry, including waist circumference, and total, central and peripheral body fat, bone mineral content and total appendicular skeletal muscle mass (ASMM) derived from dual X-ray absorptiometry.

Results: Regression analysis determined that at a BMI of 30 kg/m(2), SA European women had a %BF of 39%, which corresponded to a BMI of 29 for SA black women. For a BMI of 30 kg/m(2) in NZ Europeans, equivalent to 43% body fat, the corresponding BMIs for NZ Maori, Pacific and Asian Indian women were 34, 36 and 26 kg/m(2), respectively. Central fat mass was lower in black SA than in European SA women (P<0.001). In NZ, Pacific women had the lowest central fat mass and highest ASMM, whereas Asian Indian women had the highest central fat mass, but lowest ASMM and bone mineral content.

Conclusions: The relationship between %BF and BMI varies with ethnicity and may be due, in part, to differences in central fatness and muscularity. Use of universal BMI or waist cut-points may not be appropriate for comparison of obesity prevalence among differing ethnic groups, as they do not provide a consistent reflection of adiposity and fat distribution across ethnic groups.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • African Continental Ancestry Group / ethnology
  • African Continental Ancestry Group / genetics
  • Asian Continental Ancestry Group / ethnology
  • Asian Continental Ancestry Group / genetics
  • Body Composition / genetics
  • Body Composition / physiology*
  • Body Fat Distribution*
  • Body Mass Index*
  • Body Size / genetics
  • Body Size / physiology
  • Bone Density / genetics
  • Bone Density / physiology
  • Cross-Sectional Studies
  • European Continental Ancestry Group / ethnology
  • European Continental Ancestry Group / genetics
  • Female
  • Humans
  • Middle Aged
  • Muscle, Skeletal / physiology*
  • New Zealand
  • Obesity / ethnology*
  • Obesity / genetics
  • Obesity / physiopathology
  • Oceanic Ancestry Group / ethnology
  • Oceanic Ancestry Group / genetics
  • Regression Analysis
  • South Africa
  • Urban Population*