Association of serum sclerostin levels with low skeletal muscle mass: The Korean Sarcopenic Obesity Study (KSOS)

Background: Sclerostin is an osteocyte-derived circulating protein that inhibits the Wnt/β-catenin signaling pathway. The Wnt signaling pathway plays an important role in bone and dysregulation of the Wnt signaling pathway results in insulin resistance, inflammation, and metabolic disturbance. The aim of our study was to investigate the implication of sclerostin in low muscle mass in healthy subjects. Methods: The cross-sectional study analyzed 240 healthy non-diabetic subjects from the Korean Sarcopenic Obesity Study (KSOS). Low muscle mass was defined as the sum of the appendicular skeletal muscle mass divided by the square of height (ASM/height²) as proposed by the Asian Working Group for Sarcopenia. Results: Serum sclerostin was significantly higher in the low muscle mass group than the normal muscle mass group (151.3 [79.2-187.9] vs. 74.8 [47.6-119.6] pg/mL, p = 0.001). In the partial correlation analyses adjusted for age, sex, and body mass index, ASM/height² was negatively associated with sclerostin levels (r = −0.245, p < 0.001). Furthermore, sclerostin levels decreased linearly according to the first, second, and third tertiles of ASM/height² even after adjusting for sex, age, body mass index, life style parameters, fasting plasma glucose, bone mineral content (BMC), and total body fat mass. Conclusions: Serum sclerostin levels were negatively correlated to skeletal muscle mass independent of confounding factors including BMC and total body fat mass.