Objective: To study the relationship between percent body fat and body mass index (BMI) in different ethnic groups and to evaluate the validity of the BMI cut-off points for obesity.
Design: Meta analysis of literature data.
Subjects: Populations of American Blacks, Caucasians, Chinese, Ethiopians, Indonesians, Polynesians and Thais.
Measurements: Mean values of BMI, percent body fat, gender and age were adapted from original papers.
Results: The relationship between percent body fat and BMI differs in the ethnic groups studied. For the same level of body fat, age and gender, American Blacks have a 1.3 kg/m2 and Polynesians a 4.5 kg/m2 lower BMI compared to Caucasians. By contrast, in Chinese, Ethiopians, Indonesians and Thais BMIs are 1.9, 4.6, 3.2 and 2.9 kg/m2 lower compared to Caucasians, respectively. Slight differences in the relationship between percent body fat and BMI of American Caucasians and European Caucasians were also found. The differences found in the body fat/BMI relationship in different ethnic groups could be due to differences in energy balance as well as to differences in body build.
Conclusions: The results show that the relationship between percent body fat and BMI is different among different ethnic groups. This should have public health implications for the definitions of BMI cut-off points for obesity, which would need to be population-specific.