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

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

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.

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.

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.