Estimation of body composition from total body potassium [⁴⁰K] counts among college women

Abstract 

The body composition of 58 college women was determined by whole body ⁴⁰K count; skinfold measurements at four sites; creatinine equivalence and from prediction equation of body water. Lean body mass (LBM) estimated from measurement with skinfold-thickness agreed quite well with the respective values estimated from the total body water prediction equation. Good agreement was also found with whole body ⁴⁰K count only among obese females (BMI > 30 kg/m²). Whole body ⁴⁰K counts tended to overestimate the LBM among females with normal BMI (18.5 − <25 kg/m²) and among overweight females (25-30 kg/m²). Measure of muscle mass from the urinary creatinine equations gave inferior values for all studied females compared with the respective mean values obtained with the other three methods. Comparison between the three methods, showed significant correlations. Method selection must thus be considered in the interpretation of inter-study comparisons and follow-up of sliming regimen. The present results suggest that additional studies should be done on subpopulation groups from the same community to assess small changes in body composition.

Keywords:  Body composition, Total body potassium, BMI, Urinary Creatinine