Calf circumference as a surrogate marker of muscle mass for diagnosing sarcopenia in Japanese men and women

Aim: To examine the relationship between calf circumference and muscle mass, and to evaluate the suitability of calf circumference as a surrogate marker of muscle mass for the diagnosis of sarcopenia among middle-aged and older Japanese men and women. Methods: A total of 526 adults aged 40-89 years participated in the present cross-sectional study. The maximum calf circumference was measured in a standing position. Appendicular skeletal muscle mass was measured using dual-energy X-ray absorptiometry, and the skeletal muscle index was calculated as appendicular skeletal muscle mass divided by the square of the height (kg/m²). The cut-off values for sarcopenia were defined as a skeletal muscle index of less than -2 standard deviations of the mean value for Japanese young adults, as defined previously. Results: Calf circumference was positively correlated with appendicular skeletal muscle (r=0.81 in men, r=0.73 in women) and skeletal muscle index (r=0.80 in men, r=0.69 in women). In receiver operating characteristic analysis, the optimal calf circumference cut-off values for predicting sarcopenia were 34cm (sensitivity 88%, specificity 91%) in men and 33cm (sensitivity 76%, specificity 73%) in women. Conclusions: Calf circumference was positively correlated with appendicular skeletal muscle mass and skeletal muscle index, and could be used as a surrogate marker of muscle mass for diagnosing sarcopenia. The suggested cut-off values of calf circumference for predicting low muscle mass are <34cm in men and <33cm in women.