ABSTRACT
BACKGROUND: The prevention and treatment of diseases related to changes in body composition require accurate methods for the measurement of body composition. However, few studies have dealt specifically with the assessment of body composition of undernourished older subjects by different methodologies. OBJECTIVES: To assess the body composition of undernourished older subjects by two different methods, dual energy x-ray absorptiometry (DXA) and bioelectric impedance (BIA), and to compare results with those of an eutrophic group. DESIGN: The study model was cross-sectional; the study was performed at the University Hospital of the School of Medicine of Ribeirão Preto, University of São Paulo, Brazil. PARTICIPANTS: Forty-one male volunteers aged 62 to 91 years. The groups were selected on the basis of anamnesis, physical examination and nutritional assessment according to the Mini Nutritional Assessment (MNA) score. Body composition was assessed by DXA and BIA. RESULTS: Body weight, arm and calf circumference, body mass index (BMI), fat free mass (FFM) and fat mass (FM) were significantly lower in the undernourished group as compared to the eutrophic group. There were no significant differences between FFM and FM mean values determined by DXA and BIA in both groups, but the agreement between methods in the undernourished group was less strong. CONCLUSION: Our results suggest caution when BIA is to be applied in studies including undernourished older subjects. This study does not support BIA as an accurate method for the individual assessment of body composition.
Subject(s)
Body Composition , Electric Impedance , Geriatric Assessment , Malnutrition , Nutrition Assessment , Absorptiometry, Photon/methods , Aged , Aged, 80 and over , Body Weights and Measures , Brazil , Cross-Sectional Studies , Humans , Male , Middle Aged , Reference Values , Reproducibility of ResultsABSTRACT
BACKGROUND: Several studies have shown that liquid and food intake interfere with the evaluation of body composition in adults. However, since there are no reports about this interference in the elderly population, the need to fast for this evaluation may be dispensable. OBJECTIVES: The objective of the present study was to assess the influence of liquid and solid food on the measurement of body composition by bioelectrical impedance analysis (BIA) and by dual energy X-ray absorptiometry (DXA). DESIGN: Forty-one male volunteers aged 62 to 87 years participated in the study. The subjects were submitted to evaluation of body composition by DXA and BIA under fasting conditions and 1 hour after the ingestion of breakfast (500 ml of orange juice and one 50 g bread roll with butter). RESULTS: There was no significant difference in the variables fat-free mass (FFM) or fat mass (FM) between the fasting condition and the evaluation performed 1 hour after the meal as measured by BIA or DXA. There was also no significant difference when the same variables were compared between methods. CONCLUSION: In the present study, the ingestion of 500 ml orange juice and of one bread roll with butter by elderly subjects did not affect the results of the parameters of body composition determined by BIA or DXA. Thus, these exams could be performed without the rigor of fasting, often poorly tolerated by the elderly.
