RELATION BETWEEN BODY-MASS INDEX AND BODY-FAT IN BLACK-POPULATION SAMPLES FROM NIGERIA, JAMAICA, AND THE UNITED-STATES

Body mass index (BMI) is the most commonly used measure of obesity, Re cently, some investigators have advocated direct measurement of adipos ity rather than use of the BMI. This study was undertaken to determine the ability of BMI to predict body fat levels in three populations of West African heritage living in different environments. A total of 1, 054 black men and women were examined in Nigeria, Jamaica, and the Uni ted States during 1994 and 1995. A standardized protocol was used to m easure height, weight, waist and hip circumferences, and blood pressur e at all sites; percentage of body fat was estimated using bioelectric al impedance analysis. Percentage of body fat and BMI were highly corr elated within site- and sex-specific groups, and the resulting r(2) ra nged from 0.61 to 0.85. The relation was quadratic in all groups excep t Nigerian men, in whom it was linear. The regression coefficients wer e similar across sites, yet the mean body fat levels differed signific antly (p < 0.001) as estimated by the intercept, making intersite comp arison difficult. Compared with BMI, percentage of body fat was not a better predictor of blood pressure or waist or hip circumference.