Interchangeability among the Percentages of Body Fat Estimated by Mid-Arm Adipose Area, Triceps Skinfold Thickness and Arm-to-Arm Segmental Bioimpedance Analysis

Abstract

Background: Assessing nutritional status based on the upper limbs is useful at the clinical level. The aim of this study is to evaluate the agreement degree of the body fat percentages (%BF) estimated by the mid-arm adipose area (%BFARM), the Siri triceps skinfold equation (%BFTRICEPS) and the arm-to-arm segmental bioimpedance analysis (%BFBIA), as well as the Siri four-skinfold equation (%BFSIRI), assessing their interchangeability. Methods: A cross-sectional study. Body fat assessments were made on a total of 145 subjects (83 males, 62 females) anthropometrically and by bioelectrical impedance analysis (Omron BF 300Ó). The agreement between methods were analyzed using the interclass correlation coefficient (ICC) and the Bland-Altman method. Results: The ICC between %BFARM and %BFTRÍCEPS was 0.8322 (CI 95% 0.7672-0.8791); between %BFARM-%BFBIA 0.7337 (0.6305-0.8080) and between %BFTRICEPS-%BFBIA 0.9290 (0.9015; 0.9488). For the Bland-Altman method, the agreement interval between %BFARM-%BFTRÍCEPS (-11.2; 16.96) and between %BFARM-%BFBIA (-13.04; 21.76) exceeded the cutoff point (±10%), but not between %BFTRICEPS-%BFBIA (-6.64; 9.6), %BFSIRI-%BFTRÍCEPS (-5.27; 4.52) and %BFSIRI-%BFBIA (-6.31; 8.52). The BMI has no bearing on the results. Conclusions: The method utilized influences the nutritional assessment made based on the upper limbs. The mid-arm adipose area method overestimated the %BF with relationship to the Siri triceps skinfold or four-skinfold equation and to the bioelectrical impedance analysis, and although this result suggests that mid-arm adipose area may not be a good indicator of global adiposity, this must be confirmed against a gold standard.