Body mass index versus percentage body fat in Chinese, African-American and Caucasian postmenopausal women

Objective: The aim of the study was to investigate in postmenopausal women whether the relationship between percentage body fat (PBF) and body mass index (BMI) differs between Asians living in Beijing (BA) and African-Americans (AA), and Caucasians (Ca) living in New York City. Methods: Healthy postmenopausal women (231 BA; 113 AA, 95 Ca), aged 50-80 years, were studied. Weight, height and PBF by dual energy X-ray absorptiometry (DXA) were measured. The relationship between PBF and BMI was assessed by multiple regression analysis. Results: Race, reciprocal of BMI (1/BMI) and the interaction between race and 1/BMI were all significantly (P<0.05) related to PBF in this sample. The slope of the line relating 1/BMI to PBF was different for BA compared to AA (P=0.01) and Ca (P=0.003) while the slopes for AA and Ca were not different (P>0.05). At lower levels of BMI, Asians tended to have higher PBF comparable to AA and Ca, while at BMI >30 BA tended to have less PBF than the other groups. Conclusion: The relation between PBF and BMI in BA postmenopausal women differs from that of AA and Ca women in this sample.