Predictive Validity of the Body Adiposity Index in Costa Rican Students

Abstract

Objective: To verify the validity of the body adiposity index (BAI) in a sample of Costa Rican students. Methods: Volunteers were 93 females (mean age 5 18.6 6 2.4 years) and 106 males (mean age 5 19.2 6 2.8 years). Dual-energy X-ray absorptiometry (DXA) was used as the “gold standard” to determine body fat percentage (BF%). Pearson’s correlation coefficient and paired samples t-test studied the association and mean differences between BAI and DXA BF%. Concordance between BAI and DXA BF% was determined by the Lin’s concordance correlation coefficient and the Bland-Altman agreement analysis. Results: Significant correlations between BAI and DXA BF% were found for females (r 5 0.74) and males (r 5 0.53) (P < 0.001). Differences between methods were found for females (BAI 5 29.3 6 4.1% vs. DXA 5 36.5 6 7.9%) and males (BAI 5 24.8 6 3.7% vs. DXA 5 21.9 6 8.6%; P < 0.001). Concordance was poor in females and males. Bland-Altman plots showed BAI underestimating and overestimating BF% in relation to the “gold standard” in females and males, respectively. Conclusions: BAI presented low agreement with BF% measured by DXA; therefore, BAI is not recommended for BF% prediction in this Central American sample studied. Am. J. Hum. Biol. 28:394–397, 2016.