International Journal of Body Composition Research 2005 Vol. 3 No. 1: 00-00
Bioelectrical impedance analysis (BIA) is commonly used to measure body composition, however limited studies of its usefulness in children with the human immunodeficiency virus (HIV) -1 infection exist. The objective of the study was to provide a BIA equation for predicting body composition in outpatient pediatric HIV populations, to compare performance of our equation to published equations derived from both non-HIV and HIV-positive pediatric populations and to evaluate performance of our equation developed in thepre-highly active antiretroviral (HAART) era, in a separate HIV-positive pediatric population on HAART.
Total body water (TBW) by deuterium dilution and BIA measures from 30 HIV-positive pediatric subjects in the pre-HAART era were used to develop an equation for estimating body composition. We evaluated 18 published pediatric BIA equations in our subjects using Bland Altman analysis, and the performance of our model in a separate HIV-positive pediatric population on HAART with dual energy X-ray absorptiometry (DXA) measures.
Using multivariate techniques, we developed a predictive equation for TBW using height2 and resistance in children off HAART that correlated well (r=.95) with FFM measures obtained by DXA in children receiving HAART. A number of published BIA equations developed in healthy children also provided good estimates of TBW or FFM in our subjects.
In conclusion: We provide a new BIA equation for estimating body composition in children on or off HAART. Thus BIA measures in HIV-infected children without clinically apparent lipodystrophy are not affected by HAART, although fat distribution cannot be welldefined by BIA. Published models derived from HIV populations do not always out-perform those derived from healthy subjects.