The impact of metabolic syndrome on changes in trunk muscle CSA: a 10-year longitudinal study.

INTRODUCTION: Few studies have investigated the relationship between metabolic syndrome (MetS) and muscle loss over a 10-year period in large working populations. This study aimed to investigate the influence of MetS-related and respiratory factors on changes in trunk muscles in the working population. MATERIALS AND METHODS: The cross-sectional areas (CSAs) of the psoas major (PM) and erector spinae (ES) were measured using abdominal low-dose CT imaging at baseline and at 10 years. Predictors of CSA loss were analyzed using multiple linear regression analysis. RESULTS: A total of 1504 males were included. The change in the CSA of the PM at 10 years decreased significantly with increasing age, BMI, abdominal circumference, visceral fat area (VFA), systolic blood pressure (sBP), and HbA1c. The change in the CSA of the ES at 10 years decreased significantly with increasing age, weight, BMI, abdominal circumference, VFA, sBP, HbA1c, and LDL level. Multiple linear regression analysis revealed that VFA and HbA1c were independently associated with PM loss, while a lower percentage vital capacity (%VC) was associated with ES loss. The ratio of forced expiratory volume in one second to forced vital capacity (FEV1.0%) at baseline was identified as a significant predictor of PM loss for individuals with MetS. CONCLUSION: Among MetS-related factors, VFA and HbA1c were associated with trunk muscle CSA loss over 10 years in the working population. Furthermore, in individuals with MetS, lower FEV1.0% was associated with PM loss.