The Associations between Muscle Ultrasound Measurements, Calf Circumference, Mid-upper Arm Circumference, and Body Mass Index

Abstract

Purpose Muscle ultrasound (US) is a trending method for sarcopenia diagnosis. In this study, we aimed to show the changes in rectus femoris (RF) muscle thickness, RF cross-sectional area, gastrocnemius medialis (GC) muscle thickness, calf circumference (CC), and mid-upper arm circumference (MAC) throughout different body mass index (BMI) categories. Therefore, we planned to find out their associations with probable sarcopenia regardless of age, sex, and BMI. Methods This cross-sectional study was conducted in geriatric outpatients (≥ 65 years). Waist circumference (WC), hip circumference (HC), MAC, CC, BMI, handgrip strength (HGS), fat-free mass index (FFMI), fat%, and muscle US measurements were obtained. Results A total of 227 patients, 62.1% female, were included. Partial correlation, controlled for age, and sex, revealed that BMI had a positive strong correlation with WC (r = 0.727), HC (r = 0.793), MAC (r = 0.637), FFMI (r = 0.632), and fat% (r = 0.620). Therefore, BMI had a positive moderate correlation with CC (r = 0.545), and a positive weak correlation with GC muscle thickness (r = 0.283). RF muscle thickness (OR 0.781, 95% CI;0.691–0.882, p < 0.001), RF cross-sectional area (OR 0.601, 95% CI; 0.480–0.753, p < 0.001), and GC muscle thickness (OR 0.869, 95% CI; 0.783–0.964), p < 0.008) were independently associated with probable sarcopenia when adjusted for age, sex, and BMI categories. There were no independent associations between BMI, CC, and MAC. Conclusion Muscle US measurements are independently associated with probable sarcopenia, regardless of age, sex, and BMI. Future prospective studies are needed to support the importance of muscle US to predict sarcopenia in patients with obesity.