Estimation Of Changes In Skeletal Muscle Mass Using Changes In Calf Circumference: WASEDA’S Health Study

Calf circumference is used as a surrogate marker of skeletal muscle mass. However, whether changes in calf circumference can be used to estimate changes in skeletal muscle mass remains unclear. PURPOSE: This longitudinal study aimed to examine the relationship between changes in calf circumference and appendicular skeletal muscle mass (ASM) and investigate the effects of age and obesity. METHODS: Two-wave cohort data from 227 adults (149 men and 78 women) aged 40-87 years (mean age, 53 ± 9 years) from the WASEDA’S Health Study were used. The maximum calf circumference was assessed while the participants were standing. ASM and body fat percentages were measured using dual-energy X-ray absorptiometry. Older adults were defined as those aged ≥60 years. Obesity was defined as a body fat percentage of ≥25% for men and ≥ 30% for women. Pearson’s correlation coefficient was calculated to assess this relationship. RESULTS: The mean follow-up period was 8.0 ± 0.4 years. The mean changes in calf circumference and ASM (follow-up - baseline value) were -0.05 ± 1.24 cm and -0.67 ± 1.03 kg, respectively. Changes in calf circumference were positively correlated with changes in ASM (both sexes, r = 0.70; men, r = 0.71; women, r = 0.71). In the subgroup analysis based on age and obesity, the positive correlations between the changes in calf circumference and ASM were similar to those in the main analysis (middle-aged, r = 0.70; older, r = 0.67; non-obese, r = 0.69; obese, r = 0.72). CONCLUSION: Changes in calf circumference may be a useful estimate of changes in skeletal muscle mass regardless of age and obesity. Further studies should be conducted with a larger sample. Supported by: Japan Society for the Promotion of Science (26242070, 18 K17982, 18H03198, 19H04008, 19H04065, and 21 K17693) and MEXT-Supported Program for the Strategic Research Foundation at Private Universities from the Ministry of Education, Culture, Sports, Science and Technology (S1511017), etc.