Additive effect of low skeletal muscle mass and abdominal obesity on coronary artery calcification

We aimed to investigate the interaction of reduced skeletal muscle mass and abdominal obesity on coronary artery calcification (CAC).

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.

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.

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.