Bioelectrical impedance vectorial analysis and nutritional status of older women according to body mass index

Authors: DE MELO, CAMILA - Universidad De Sao Paulo; KEHAYIAS, JOSEPH - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MIYAMOTO, MARCIA - University Of St Jude (USJT); RIBEIRO, SANDRA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Brazilian Journal of Kinanthropometry and Human Performance
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2011
Publication Date: 12/1/2011
Citation: De Melo, C.M., Kehayias, J.J., Miyamoto, M.V., Ribeiro, S.M. 2011. Bioelectrical impedance vectorial analysis and nutritional status of older women according to body mass index. Brazilian Journal of Kinanthropometry and Human Performance. 13(6):415-421.

Interpretive Summary: Epidemiological and clinical studies have shown that older adults with high body mass index (BMI) are able to better face stressing factors, and have better survival rate. The aim of the present study was to evaluate if higher BMI values were associated with improved nutritional status. We also examined the application of an electrophysiological response called “bioelectrical impedance vectorial analysis (BIVA)” to predict nutritional status. Thirty-two women (60 years and above; free-living and active), were distributed into three BMI groups: G1 (BMI<23kg/m2); G2 (2328Kg/m**2). We analyzed: body mass and stature to calculate BMI, waist (WC) and hip (HC) circumference and the waist/hip ratio (WHR); BIVA; resting energy expenditure (REE); and biochemical markers of nutritional status. It was found that the highest BMI values related to poor prognosis for chronic diseases. Lower BMI values indicated a fat-free mass reduction. Our results reinforce the differentiated BMI classification for the elderly. BIVA results were inconsistent.

Technical Abstract: Longitudinal studies, both epidemiological and clinical, have shown that elderly with high body mass index (BMI) are able to better face stressing factors, and have better survival rate as consequence. The aim of the present study was to evaluate if higher BMI values were associated with improved nutritional status. We also examined the ability of bioelectrical impedance vectorial analysis (BIVA) to predict nutritional status. Thirty-two women (60 years and above; free-living and active), were distributed into three BMI groups: G1 (BMI<23kg/m**2); G2 (2328Kg/m**2). We analyzed: body mass and stature to calculate BMI, waist (WC) and hip (HC) circumference and the waist/hip ratio (WHR); BIVA; resting energy expenditure (REE); and biochemical markers of nutritional status (blood glucose, total cholesterol, HDL and LDL, IGF-I and leptin). The groups were compared by ANOVA and by Hotelling’s T**2 test for vector analysis. The mean vector displacement across the groups showed lower reactance and higher resistance in G1. G3 presented the highest WC, BF, and leptin levels; REE was lower in G3. Therefore, the highest BMI values related to the best (higher phase angle) BIVA results but they were also related to poor prognosis for chronic diseases. Lower BMI values indicated a fat-free mass reduction. Our results reinforce the differentiated BMI classification for the elderly.