Additive Effect of Low Skeletal Muscle Mass and Abdominal Obesity on Coronary Artery Calcification

Objective We aimed to investigate the interaction of reduced skeletal muscle mass and abdominal obesity on coronary artery calcification (CAC). Design and methods A total of 19,728 adults free of cardiovascular disease (CVD) who contemporaneously underwent cardiac tomography and bioelectrical impedance analysis were enrolled in a cross-sectional and longitudinal cohort. Skeletal muscle mass index (SMI) was calculated the following formula: SMI (%) = total appendicular muscle mass (kg)/body weight (kg) x 100 according to sex. CAC presence or incidence was defined as CAC score>0, and CAC progression was defined as √CAC score (follow-up) - √CAC score (baseline)>2.5. Pre-sarcopenia was defined as SMI ≤ -1.0 standard deviation of the sex-specific mean of a young reference group. Abdominal obesity was defined as waist circumference ≥90cm for men and ≥85cm for women. All individuals were further classified into four groups: normal, abdominal obesity alone, pre-sarcopenia alone, and pre-sarcopenic obesity. Results Individuals with pre-sarcopenic obesity showed the highest adjusted odds ratio (AOR) for CAC presence (AOR 2.16, 95% confidence interval [CI]: 1.98-2.36, P<0.001) as well as total CAC incidence and progression (adjusted hazard ratio 1.54, 95% CI: 1.37-1.75, P<0.001), compared with normal individuals. Pre-sarcopenic obesity significantly increased CAC incidence and progression compared to either pre-sarcopenia or abdominal obesity alone. Conclusion Pre-sarcopenia and abdominal obesity together were significantly associated with a higher CAC presence and increased risk of CAC incidence and progression, independent of traditional CVD risk factors.