Myostatin as a plausible biomarker for early stage of sarcopenic obesity.

Since sarcopenic obesity (SO) impacts negatively on our health, early detection of SO is essential. However, prevalence of SO in an apparently healthy population has not been well examined. This study aimed to elucidate the prevalence and related factors of SO in middle-aged women, and to investigate useful diagnostic criteria for SO. Body component analyses were conducted on 432 female Osaka University employees aged 30-59 during their health checkups. Healthy (H) and SO groups were defined using cutoff values of 5.7 kg/m for skeletal muscle mass index and 30% for percent body fat. Serum myostatin and insulin levels were additionally measured. Among 432 participants, the prevalence of SO was 6.3%. Grip strength (P < 0.0001) was lower and triglyceride (P = 0.0004) and low-density lipoprotein cholesterol (P = 0.0105) levels, and Homeostatic Model Assessment of Insulin Resistance (P = 0.0262) were higher in the SO group than in the H group. Serum myostatin levels in the SO group were lower than in the H group (3,107 pg/mL vs. 3,957 pg/mL, P = 0.0003). Myostatin levels may be suppressed in individuals with SO without any pre-existing conditions. Our diagnostic criteria for SO could reveal the risks for metabolic-related diseases and may be useful for the early detection of SO.