Background: The purpose of this study was to explore the optimal cut-off point of calf circumference (CC) as a simple proxy marker of appendicular skeletal muscle mass (ASM) and sarcopenia in the Korean elderly and to test the criterion-related validity of CC by analyzing its relationships with the physical function.
Methods: The participants were 657 adults aged 70 to 84 years who had completed both dual energy X-ray absorptiometry (DXA) and physical function test in the first baseline year of the Korean Frailty and Aging Cohort Study.
Results: ASM and skeletal muscle mass index (SMI) were correlated positively with CC (male, ASM, r = 0.55 and SMI, r = 0.54; female, ASM, r = 0.55 and SMI, r = 0.42; all P < 0.001). Testing the validity of CC as a proxy marker for low muscle mass, an area under the curve (AUC) of 0.81 for males and 0.72 for females were found and their optimal cut-off values of CC were 35 cm for males and 33 cm for females. In addition, CC-based low muscle groups were correlated with physical functions even after adjusting for age and body mass index. Also, the cut-off value of CC for sarcopenia was 32 cm (AUC; male, 0.82 and female, 0.72).
Conclusion: The optimal cut-off values of CC for low MM are 35 cm for males and 33 cm for females. Lower CC based on these cut-off values is related with poor physical function. CC may be also a good indicator of sarcopenia in Korean elderly.
Keywords: Aged; Anthropometry; Korea; Muscle Mass; Sarcopenia.