Anthropometry based Predictive Equations for Estimating Nigerian Women Percentage Body Fat using Stable Isotope Technique as Reference

Abstract

The direct measurement of body composition using innovative non-or minimally-invasive technologies such as stable isotope technique, despite its reliability and precision remains a significant challenge.  This study was designed to develop predictive equations for estimating the percentage body fat of Nigerian women using isotope dilution (ISD) or gold standard technique (as in IAEA procedure) as reference and validated by bioelectrical impedance technique.The percentage body fats (% BF) of 173 Nigerian women (aged 18-55 yrs) were estimated using isotope dilution (ISD) or gold standard technique (as in IAEA procedure) as reference and validated by bioelectrical impedance technique. The skinfold thicknesses (mm) such as biceps, triceps, subscapular, suprailiac and abdominal were measured using skinfold langre callipers while body circumferences such as forearm, wrist, waist, abdominal and hip were measured using standard tape rule and in accordance with WHO guidelines. The subjects’ percentage body fat (%BF) ranged from 8.0 to 48.5. Generally, at 0.01 level of significance (Using Statistical Package for Social Scientists (SPSS), higher positive significant correlations were obtained between % BF by ISD and body circumferences (r=0.503-0.874) than skinfold thicknesses (r=0.503-0.739). Using forward selection regression procedure, three sex-specific based predictive equations for estimating %BF (incorporating subjects’ weight and body circumferences such as hip, abdominal and waist) were developed based on the subjects’ ethnic groups (Yoruba, Hausa and Ibos) with high R2 (0.853, 0.953 & 0.867) and low Pure errors (3.316, 2.791 & 2.324) respect. These equations provide easy way of measuring percentage body fat and are recommended for use in clinical or epidemiological settings in populations with similar ethnic background and in lieu of isotope dilution method.