2023-11-302025-07-282023-11-302023-11-301932-6203https://ir.ntus.edu.tw/handle/987654321/65078For the assessment of sarcopenia or other geriatric frailty syndromes, psoas major area may be one of the primary indicators. Aim to develop and cross-validate the psoas cross-sectional area estimation equation of L3-L4 of the elderly over 60 years old by bioelectrical impedance analysis (BIA). Ninety-two older adults with normal mobility were enrolled (47 females, 45 males), and were randomly divided into a modeling group (MG, n = 62) and validation group (VG, n = 30). Computed tomography (CT) was used to measure the psoas major area at the' L3-L4 lumbar vertebrae height as a predictor. Estimated variables were height (h), whole body impedance (Z(whole)), whole body impedance index (h(2)/Z(whole), WBI), age, gender (female = 0, male = 1), and body weight (weight) by standing BIA. Relevant variables were estimated using stepwise regression analysis. Model performance was confirmed by cross-validation. BIA estimation equation for PMM obtained from the MG was: (PMMBIA = 0.183 h(2)/Z- 0.223 age + 4.443 gender + 5.727, r(2) = 0.702, n = 62, SEE = 2.432 cm(2), p < 0.001). The correlation coefficient r obtained by incorporating the VG data into the PMM equation was 0.846, and the LOA ranged from -4.55 to 4.75 cm(2). PMMBIA and PMMCT both correlate highly with MG or VG with small LOA. The fast and convenient standing BIA for measuring PMM may be a promising method that is worth developing.110 bytestext/htmlBIOELECTRICAL-IMPEDANCE ANALYSISSKELETAL-MUSCLEWHOLE-BODYSIZEMASSSARCOPENIAGEOMETRYATROPHYSINGLEWOMENarticle