Accuracy of octa-polar bioelectrical impedance analysis for the assessment of total and appendicular body composition in children and adolescents with HIV: comparison with dual energy X-ray absorptiometry and air displacement plethysmography.

BACKGROUND: Body composition analysis has been used to investigate fat mass (FM) and bone mineral content (BMC) in children and adolescents diagnosed with HIV. Investigating the validity of bioelectrical impedance analysis (BIA) is interesting with respect to testing useful techniques for monitoring body composition in children and adolescents in clinical practice. The present study aimed to determine the validity of body composition analysis by BIA compared to dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP) in children and adolescents an HIV diagnosis. METHODS: Sixty-four children and adolescents (35 females and 29 males) with a mean (SD) age of 12.22 (2.13) years and with an HIV diagnosis participated in the study. Fat-free mass (FFM), FM and body fat percentage (%BF) were obtained by BIA for comparison with DXA and ADP. Segmented FM (trunk, legs and arms), lean soft tissue mass (LSTM) (total and segmented) and BMC were obtained by BIA for comparison with DXA. RESULTS: BIA presented a clinically acceptable correlation with DXA and ADP for FFM. Values found by BIA were underestimated compared to ADP, and overestimated compared to DXA. BIA presented a clinically acceptable correlation with DXA for LSTM estimates (total and segmented parameters) in both sexes (underestimating FM and overestimating LSTM). For other components (%BF, FM and BMC), BIA had a clinically unacceptable correlation with the reference methods in both sexes. CONCLUSIONS: BIA was suitable for evaluating FFM and LSTM in children and adolescents with an HIV diagnosis. For FM, %BF and BMC, BIA was not suitable for performing an evaluation in both sexes.

Comparison of body adiposity index (BAI) and air displacement plethysmograph with estimations of % body fat in adults with Down's syndrome.

BACKGROUND/OBJECTIVES: The aim of this study was to verify the agreement between body fat percentage (%BF) values evaluated by air displacement plethysmograph (ADP) and body adiposity index (BAI) in adults with Down's syndrome (DS). SUBJECTS/METHODS: Forty-five adults with DS volunteered to participate in this study (19 women; age 28.7±8.5 years and 26 men; age 29.1±8.8 years). The %BF was measured by ADP (%BFADP) and estimated by anthropometric measures [%BF=(hip circumference/height)1.5-18] (%BFBAI). Agreement between methods was evaluated by paired t-test, Pearson's correlation coefficient and Bland-Altman analysis. RESULTS: Although high correlation coefficients were found between %BFADP and %BFBAI for women (r=0.78, P<0.05) and men (r=0.87, P<0.05), significant differences were observed between methods for both sexes (38.9±8.9 vs 42.5±8.5% for women, and 25.8±11.3 vs 32.6±5.4% for men in %BFADP and %BFBAI, respectively). Moreover, Bland-Altman analysis showed that the mean error estimate was +3.6 (95%CI, -7.59 to 14.79) in women and +6.74 (95%CI, -7.25 to 20.72) in men. CONCLUSIONS: The results indicate that BAI seems to be a limited method to evaluate %BF in women and in men with DS.