BIOELECTRICAL IMPEDANCE WITH DIFFERENT EQUATIONS VERSUS DEUTERIUM OXIDE DILUTION METHOD FOR THE INFERENCE OF BODY COMPOSITION IN HEALTHY OLDER PERSONS

There is no consensus regarding the accuracy of bioimpedance for the determination of body composition in older persons. Objective: This study aimed to compare the assessment of lean body mass of healthy older volunteers obtained by the deuterium dilution method (reference) with those obtained by two frequently used bioelectrical impedance formulas and one formula specifically developed for a Latin-American population. Design: A cross-sectional study. Participants: Twenty one volunteers were studied, 12 women, with mean age 72±6.7 years. Setting: Urban community, Ribeirão Preto, Brazil. Measurement: Fat free mass was determined, simultaneously, by the deuterium dilution method and bioelectrical impedance; results were compared. In bioelectrical impedance, body composition was calculated by the formulas of Deuremberg, Lukaski and Bolonchuck and Valencia et al. Results: Lean body mass of the studied volunteers, as determined by bioelectrical impedance was 37.8±9.2 kg by the application of the Lukaski e Bolonchuk formula, 37.4±9.3 kg (Deuremberg) and 43.2±8.9 kg (Valencia et. al.). The results were significantly correlated to those obtained by the deuterium dilution method (41.6±9.3 Kg), with r=0.963, 0.932 and 0.971, respectively. Lean body mass obtained by the Valencia formula was the most accurate. Conclusion: In this study, lean body mass of older persons obtained by the bioelectrical impedance method showed good correlation with the values obtained by the deuterium dilution method. The formula of Valencia et al., developed for a Latin-American population, showed the best accuracy.