A WHO expert consultation, chaired by Professor Shiriki Kumanyika from the University of Pennsylvania School of Medicine, USA, discussed the merits of BMI as an indicator of health outcomes across different ethnic populations. The increased body-fat proportions of some Asian populations suggest that a lower BMI (22-25 kg/m2) may be a more appropriate upper cut-off point; values above this adjusted threshold would indicate increased risk of adverse health outcomes.
The consultation concluded that the proportion of Asian people with a high risk of type 2 diabetes and cardiovascular disease is substantial at BMIs lower than the existing WHO cut-off point for overweight (*25 kg/m2). However, the authors discuss how available data do not necessarily indicate a clear BMI cut-off point for all Asians for overweight or obesity. The cut-off point for observed risk varies from 22 kg/m2 to 25 kg/m2 in different Asian populations; for high risk it varies from 26 kg/m2 to 31 kg/m2. No attempt was made, therefore, to redefine cut-off points for each population separately.
The consultation also agreed that the WHO BMI cut-off points - * 25 kg/m2 (overweight), 25-29.9 kg/m2 (pre-obese), * 30 kg/m2 (obesity), 30- 34.9 kg/m2 (obese class I), 35-39.9 kg/m2 (obese class II), * 40 kg/m2 (obese class III) - should be retained as international classifications. However, the consultation identified potential intermediate public-health action points (23.0, 27.5, 32.5, and 37.5 kg/m2) along the continuum of BMI, and proposed methods by which countries could make decisions about the definitions of increased risk for their population.
Dr. Chizuru Nishida, Scientist, Department of Nutrition for Health and Development (NHD), World Health Organisation (WHO), 20 Avenue Appia, CH-1211 Geneva 27, Switzerland; T): 41-22-791-3317/3455; F): 41-22-791-4156; E): firstname.lastname@example.org.
Dr. Shiriki Kumanyika, Professor of Epidemiology, University of Pennsylvania School of Medicine, CCEB, 3401 Market Street, Suite 202, Philadelphia, PA, 19104, USA; T): 215-573-8927; F): 215-573-5311; E): email@example.com.