Development of Estimate Formulas for Appendicular Lean Mass Using Forearm Circumference in Older Adults Requiring Care.

Abstract

Objectives: The use of forearm circumference (FC) in the estimation equation to predict appendicular lean mass (ALM) in older adults who require care remains unclear.

Methods: This cross-sectional study targeted 132 participants aged ≥65 years requiring care. The ALM was measured with bioelectrical impedance analysis (BIA). Handgrip strength (HS) was measured with a digital hand dynamometer. FC was measured at the site of maximum swelling using a tape measure. Multiple regression analysis was conducted to develop an equation for estimating BIA-measured ALM using FC. Moreover, we investigated a systematic error by Bland-Altman analysis between BIA-measured ALM and ALM calculated by the estimation equation.

Results: We developed the four estimation equations. The values of r, adjusted R², and SEE in the representative model (FC + HS + age) were 0.86, 0.73, and 2.01 (kg), respectively (p < 0.05). In contrast, a systematic error was identified between the BIA-measured ALM and ALM calculated by the estimation equations by the Bland-Altman analysis.

Conclusions: This study developed the formula using FC, which can predict ALM with less influence of edema, but it may over- or underestimate ALM in older adults requiring care.