Upper-Arm Anthropometry: An Alternative Indicator of Nutritional Health to Body Mass Index in Unilateral Lower-Extremity Amputees?

Abstract

Miller M, Wong WK, Wu J, Cavenett S, Daniels L, Crotty M. Upper-arm anthropometry: an alternative indicator of nutritional health to body mass index in unilateral lower-extremity amputees? Objective To evaluate the utility of body mass index (BMI) and corrected-arm-muscle area (CAMA) as measures of nutritional health for lower-limb amputees attending prosthetics clinics. Design Cross-sectional study. Setting Prosthetics clinic in Australia. Participants Unilateral lower-extremity amputees (N=58; age range, 21–91y; 37 transtibial, 21 transfemoral) attending a regional prosthetics clinic between May and November 2003. Interventions Not applicable. Main Outcome Measures Weight (without prosthesis), corrected and uncorrected for the amputated limb was used with height estimated from knee height to calculate corrected BMI (cBMI) and uncorrected BMI (uBMI). CAMA was calculated using the mean of triplicate mid-upper-arm circumference (MUAC) and triceps skinfold thickness (TST) measurements. The Mini Nutritional Assessment (MNA) and Assessment of Quality of Life were administered according to recommended protocols. The Pearson correlation was used to determine the strength and significance of associations between variables, and bivariate regression analyses were performed to determine whether an association existed between the nutritional variables (BMI, CAMA, MNA) and quality of life (QOL). Results There were no statistically significant differences in the measures of nutritional health according to site (transtibial, transfemoral) of amputation. MUAC, TST, and CAMA all showed moderate to high positive correlations ( r range, .541−.782) with both cBMI and uBMI. The strength of the relationship between the MNA and cBMI/uBMI was weaker ( r=.383, r=.380, respectively) but remained positive and statistically significant ( P=.003). QOL was not associated with cBMI or uBMI but was related to CAMA (β=−.132; P=.030) and MNA (β=−.561; P=.017). Conclusions For persons with unilateral lower-extremity amputation, measurement of upper-arm anthropometry may be a more useful indicator of nutritional health and its consequences than BMI.