Title of article:
Differences in body-composition assumptions across ethnic groups: practical consequences.
Authors: Deurenberg P, Deurenberg-Yap M.
Journal: Curr Opin Clin Nutr Metab Care 2001 Sep;4(5):377-83
Body-composition methodologies rely on assumptions that are not constant across ethnic groups. The consequence is that the methods used need to be population specific to guarantee unbiased conclusions. Alternatively, assumption-free methods such as chemical multiple-compartment models or scanning techniques should be used. Adequate and unbiased scientific data on body fat among ethnic population groups are necessary for a better understanding of the aetiology of obesity and its co-morbidities. The World Health Organization cut-off points for underweight, overweight, obesity and fat distribution, now universally defined, may need revision because the relationship between body mass index and body composition, and between indices of fat distribution and the actual amount of visceral fat, differ across ethnic groups. The need for ethnically specific cut-off points for obesity and fat distribution is substantiated, for example, by elevated disease risks at low levels of body mass index in several populations. Properly designed and conducted studies are needed to obtain unbiased information on these topics.
Comments and Key points
This article is a tour-de-force summary of many of the reasons why different racial group/ethnicities/nationalities should have different BMI overweight criteria. Below are some excerpts that I found useful, when I searched for race-specific Body Mass Index adjustments for Black Americans and Asians.
- "It is now generally accepted that African-Americans have a higher bone mineral density and bone mineral content than whites, and that their muscle mass is higher1."
- "It is now generally believed that African-Americans have less visceral fat than matched (for age, BMI, circumference ratios) Caucasian Americans." "the lower amount of visceral adipose tissue among American Blacks (matched for BMI) could turn out to be an artefact, as their total body-fat levels could be lower."
- "The bioelectrical impedence of the body is, to a large extent, determined by the impedance of the limbs2... and there are clear differences in limb length between ethnic groups."
- "Subjects with relatively long legs will have lower BMIs... (for example) the 'longleggedness' of the Australian aboriginals contributes to 2 kg/m2 to their low BMI3."
- "Hong Kong Chinese have high BF% (body fat percentage) values at low BMIs and proposed BMI cut-off points for overweight and obesity as low as 23 and 26 kg/m2, respectively.4"
- "In Indonesia, the BMI cut-off for obesity has been set at 27 kg/m2."
- Wagner DR, Heyward VH. Measures of body composition in blacks and whites: a comparative review. Am J Clin Nutr 2000; 71:1392-1402.
- Fuller NJ, Elia M. Potential use of bioelectrical impedance of the 'whole body' and of body segments for the assessment of body composition: comparison with densitometry and anthropometry. Eur J Clin Nutr. 1989; 43:779-791.
- Norgan NG. Interpretation of low body mass indices: Australian Aborigines. Am J Physical Anthropol 1994; 94;229-237.
- Ko GTC, Tang J, Chan JCN, et al. Lower BMI cut-off value to define obesity in Hong Kong Chinese: an analysis based on body fat assessment by bioelectrical impedance. Br J Nutr. 2001; 85:239-242.
Review & comments by Steven B. Halls, MD, Last modified
23-June, 2008, Copyright
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