Resumen

VELAZQUEZ-ALVA, Maria del Consuelo; IRIGOYEN-CAMACHO, Maria Esther; HUERTA-HUERTA, Raquel  y  DELGADILLO-VELAZQUEZ, Jaime. A comparison of dual energy X- ray absorptiometry and two bioelectrical impedance analyzers to measure body fat percentage and fat-free mass index in a group of Mexican young women. Nutr. Hosp. [online]. 2014, vol.29, n.5, pp.1038-1046. ISSN 1699-5198.  https://dx.doi.org/10.3305/nh.2014.29.5.7254.

Introduction: Studies of obesity require the estimation of fat mass (FM) and fat-free mass (FFM); therefore it is important to validate methods that evaluate these measurements. Objective: We sought to compare two different bioelectrical impedance analysis systems (BIAs) to estimate FM and FFM using dual-energy X-ray absorptiometry (DXA) as reference. Methods: We used a cross-sectional design. We evaluated FM and FFM using DXA and two types of BIA equipment: a foot-foot system (FFS) and a hand-footsystem (HFS). We conducted paired analysis (paired t-test). We used Bland-Altman plots to assess the relationships between FM and FFMI, limits of agreement were constructed (CL). Results: A total of 175 female students (22.9 ± 2.2 years-old) participated in the study. The paired analysis showed significant differences between the mean value of body fat percentage (BF%) estimated by BIA equipment compared to DXA (FFS = 28.7%, HFS= 34.4% and DXA= 35.3%). The mean difference between the HFS and DXA of BF% was -0.96, ((CL -5.29, 7.20). For the FFS, the mean difference was -6.69, (CL -0.29, -13.09). The paired analysis revealed significant differences between the estimates of FFMI by BIA compared to DXA (FFS =16.29, HFS =14.95, DXA =14.18). The mean difference between HFS and DXA was 0.78, and (CL -2.27, 0.72) whereas the FFS mean difference was -2.11 (CL -3.73 -0.49). Conclusion: A different magnitude of bias was observed between the BIA equipment arrays. The HFS appears to be more reliable than the FFS used, particularly in obtaining FFMI in young women.

Palabras clave : Body composition; Body fat; Fat-free mass index; BIA; DXA; Validation.

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