Relationship between metabolic syndrome and trunk muscle quality as well as quantity evaluated by computed tomography

Abstract

Metabolic syndrome is a cluster of metabolic abnormalities. Skeletal muscle attenuation and area evaluated by computer tomography (CT) may provide valuable information about patients with metabolic disorder. Therefore, we examined the association between skeletal muscle characteristics and metabolic syndrome, and investigated the combined effect of quantitative and qualitative muscle parameters. In this cross-sectional study, we analyzed 808 middle-aged Japanese subjects. The cross-sectional area of skeletal muscle was evaluated based on CT at the third lumbar vertebrae. The subjects were divided into four groups according to the median levels of skeletal muscle index (SMI) and density (SMD). Eighty-five men and twenty-two women had metabolic syndrome. In the adjusted model, SMI and SMD had an interaction effect on the number of metabolic syndrome components (p=0.0398 in men and p=0.0306 in women). When SMI and SMD were considered as independent variables for multiple regression analysis, SMI (β=-0.155, p=0.0019 in men and β=-0.295, p<0.0001 in women) and SMD (β=-0.355, p<0.0001 in men and β=-0.324, p<0.0001 in women) were both independently associated with the number of metabolic syndrome components. The subgroup with presence of low SMI and low SMD levels had a significantly higher prevalence of metabolic syndrome than that observed in other groups. Therefore, we suggest that not only muscle quantity but also quality is independently associated with metabolic syndrome.