Sarcopenia and Sarcopenic Obesity in Postmenopausal Women: Limitations of BMI as a Predictor of Sarcopenic Obesity

Abstract

ABSTRACT Objectives The study aimed to assess the prevalence of sarcopenia and sarcopenic obesity among community‐dwelling postmenopausal women. It also examined predictors of these conditions and their association with bone fragility. Methods The cross‐sectional study included 300 community‐dwelling ambulant postmenopausal women aged 50 years or older recruited over 2 years. All participants underwent assessment of body mass index, bone mineral density, and body composition by dual‐energy X‐ray absorptiometry. Sarcopenia was diagnosed as per the Asian Working Group for Sarcopenia (AWGS) criteria. Sarcopenic obesity was defined as the presence of low muscle mass (relative appendicular skeletal mass‐RASM < 5.4 kg/m2) and increased total fat mass% > 40%. Results The mean (SD) age and body mass index of the participants were 61.9 (6.8) years and 25.3 (4.8) kg/m2, respectively. Sarcopenia and sarcopenic obesity were identified in 43.7% and 27% of participants, respectively, while 48% had osteoporosis at any site. Although fat mass percentage was lower in those with sarcopenia, multivariable analysis adjusted for age, body mass index, and bone density identified higher fat mass percentage (aOR 1.715, p < 0.001) and lower body mass index (aOR 0.279, p < 0.001) as independent predictors. Receiver operating characteristic (ROC) analysis demonstrated good discrimination for body mass index (AUC 0.894) and modest discrimination for fat mass percentage (AUC 0.652); a combined model using body mass index and fat mass percentage improved prediction substantially (AUC 0.946). For sarcopenic obesity, lower body mass index (aOR 0.913, p = 0.010) and higher age (aOR 1.057, p = 0.010) were significant predictors. Conclusion Sarcopenia and sarcopenic obesity were prevalent among community‐dwelling postmenopausal women, with lower body mass index identified as a significant predictor of both conditions. The observation that low body mass index predicts both sarcopenia and sarcopenic obesity highlights the limitations of body mass index as a measure of adiposity when assessing sarcopenic obesity in postmenopausal women.