Association between metabolic syndrome and limb muscle quantity and quality in older adults: a pilot ultrasound study

PURPOSE: Limited imaging studies have investigated whether limb muscle quantity and quality change after metabolic syndrome (MetS) development. This pilot study examined MetS influence on limb muscle characteristics in older adults. METHODS: Participants were recruited from annual health examinations; their right biceps brachii, triceps brachii, rectus femoris, and gastrocnemius muscles were measured by ultrasound. Anthropometric parameters, blood biochemistry, and physical performance (handgrip strength and gait speed) were also examined. RESULTS: Overall, 129 participants were enrolled, including 26 with MetS. Although handgrip strength was lower in MetS patients, there were no significant between-group differences considering thickness and mean echogenicity of the four muscles. Handgrip strength was positively correlated with the thickness of biceps brachii, triceps brachii, and rectus femoris but was negatively associated with their echogenicity. On multivariate analysis, triceps muscle echogenicity was trivially associated (odds ratio, 0.93; 95% confidence interval, 0.86–0.99) with MetS, possibly due to multicollinearity with grip strength. CONCLUSION: No significant difference was recognized in limb muscle thickness and echogenicity in the geriatric population with MetS compared with healthy controls by ultrasound imaging. However, the finding might be caused by the small sample size of our participants. Future large-scale studies should explore the influence of separated risk factors of MetS on limb muscle echotexture and examine whether manifestation differs in different age populations.