Body adiposity index performance in estimating body fat in a sample of severely obese Brazilian patients

BACKGROUND/OBJECTIVES The body adiposity index (BAI) estimates the amount of body fat (BF) in humans. In Mexican-American and African-American populations, BAI has performed better than body mass index (BMI). The aim of this study was to evaluate the performance of BAI in estimating percentage (BF%) in severely obese Brazilian patients, with air displacement plethysmography (ADP) used as the reference method. SUBJECTS/METHODS Estimation of BF% by ADP, anthropometric measurements (height, abdominal and hip circumferences, body weight, and BMI) and BAI calculation were performed in 72 obese subjects (BMI ≥ 30 kg/m(2)) aged 30-55 years. RESULTS The mean BF% estimates ± standard deviation were 52.1 ± 5.7 % for ADP and 47.7 ± 7.4% for BAI, with a positive Pearson correlation (rp = 0.66) and a positive Lin's concordance correlation (rc = 0.479) observed between these methods. The 95% limits of individual agreement between BAI and ADP ranged from -5.769% to 16.036%, with BAI exhibiting an average positive bias of 5.13% compared to the reference method. For each studied variable, BAI exhibited a systematic bias, as evidenced by a tendency for low BF% values to be overestimated. CONCLUSION For Brazilian patients with severe obesity, BAI does not provide an accurate estimate of BF%.