Evaluation of the Body Adiposity Index in a Caucasian Population: The Hordaland Health Study

In this study, we compared the relationships of body mass index (BMI) and body adiposity index (BAI) with body fat percentage (BF%) in a Caucasian, European population. BF% was measured by dual-energy x-ray absorptiometry in a population-based cross-sectional study of 5,193 middle-aged (47-49 years) and elderly (71-74 years) men and women from the Hordaland Health Study in western Norway from 1997 to 1999. In the total population, the correlation between BAI and BF% was stronger (r=0.78) than the correlation between BMI and BF% (r=0.56) with similar results in the middle-aged and elderly groups. However, in men and women separately, BMI was a better correlate of BF% (for men, r=0.76; for women, r=0.81) than was BAI (for men, r=0.57; for women, r=0.72). BMI was also a better correlate of BF% than was BAI assessed by partial correlations adjusted for sex (for BMI-BF%, r=0.79; for BAI-BF%, r=0.67). Bland-Altman plots and BF%-stratified analyses showed that BAI tended to overestimate BF% in lean subjects and to underestimate it in those with higher proportions of body fat, but that it predicted BF% well for those whose BMI was in a normal range. At the individual level and in population studies adjusted for sex, BMI outperforms BAI as a predictor of BF%.