Association between appendicular skeletal muscle mass and myocardial glucose uptake measured by 18F-FDG PET.

Background: Low muscle mass is associated with high insulin resistance and an increased risk of cardiovascular disease. This study aims to determine whether low muscle mass affects the alterations in myocardial substrate metabolism that are associated with the development of cardiovascular disease.

Method: The study included 299 individuals (182 men and 117 women) who underwent examination at the Severance Health Check-up Center between January 2018 and February 2019. Myocardial glucose uptake was assessed using [18F]-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET/CT) scanning. Direct segmental bioimpedance analysis was used to measure appendicular skeletal muscle mass (ASM).

Results: We analysed men and women separately owing to sex-related body composition differences. ASM/Ht² was significantly positively correlated with myocardial glucose uptake measured by ¹⁸F-FDG PET/CT [ln (SUV_heart/liver)] only in men (r = 0.154, P = 0.038 in men; r = -0.042, P = 0.652 in women, respectively). In men, myocardial glucose uptake was significantly associated with ASM/Ht² even after adjusting for multiple confounders in a multivariable linear regression model (standardized β = 0.397, P = 0.004, in men; β = - 0.051, P = 0.698, in women). In women, age (β = -0.424 P = 0.029) was independent determinants of myocardial glucose uptake.

Conclusions: In men, ASM was strongly associated with myocardial glucose uptake as measured by ¹⁸F-FDG PET/CT. In women, age was significantly correlated with myocardial substrate utilization, but not with ASM.