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 using the following formula: SMI (%) = total appendicular muscle mass (kg)/body weight (kg) × 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 s.d. of the sex-specific mean of a young reference group. Abdominal obesity was defined as waist circumference ≥ 90 cm for men and ≥85 cm 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% 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.