UC San Diego

Background

Atherosclerosis is a major risk factor for morbidity and mortality. However, epidemiologic data are sparse regarding risk factors for superior mesenteric artery calcification (SMAC), the association between SMAC and disease in other arterial beds, or the independent contribution of SMAC to risk of mortality. The objective of this study was to test the hypothesis that presence and extent of SMAC are associated with cardiovascular disease (CVD) risk factors, calcification in other arterial beds, and both cardiovascular and all-cause mortality, independent of classic risk factors and calcification in other arterial beds.

Methods

Arterial calcification in the superior mesenteric artery, celiac trunk, coronaries, thoracic aorta, abdominal aorta, and iliac arteries was evaluated by computed tomography in adults with no known CVD. Multiple logistic regression models examined risk factor associations for SMAC and SMAC as a risk factor for calcification in other arterial beds. Cox models were used to examine the association between SMAC and mortality.

Results

The average age of subjects was 56 years; 43.7% (1877/4300) were women, and 6.7% (290) had SMAC. Age (odds ratio [OR], 1.09; 95% confidence interval, 1.06-1.11), male sex (OR, 1.79; 95% CI, 1.08-3.03), dyslipidemia (OR, 1.38; 95% CI, 1.01-1.88), and any smoking (OR, 1.60; 95% CI, 1.20-2.14) were associated with SMAC presence. Notably, body mass index, body fat percentage, hypertension, diabetes, and family history of coronary heart disease were not significant risk factors for the presence of SMAC. SMAC presence was associated with calcification in all five other arterial beds (OR, 6.02; 95% CI, 3.76-9.66). During a median follow-up time of 9.4 years, there were 234 deaths, 76 of which were CVD related. SMAC extent (represented as per-unit increase in log [SMAC score + 1]; OR, 1.31; 95% CI, 1.01-1.71) was significantly associated with CVD mortality after full adjustment for risk factors and calcification in other arterial beds. SMAC presence (OR, 1.52; 95% CI, 1.10-2.12) and extent (OR, 1.25; 95% CI, 1.06-1.48) were also both significantly associated with all-cause mortality after full adjustment.

Conclusions

SMAC is associated with specific CVD risk factors as well as with calcification in all other arterial beds. SMAC extent was significantly associated with incident cardiovascular mortality, whereas both SMAC presence and extent were significantly associated with all-cause mortality, even after adjustment for risk factors and calcification in other arterial beds. Further studies are needed to determine whether SMAC is simply a marker for advanced and systemic disease or whether it confers increased mortality risk through an independent mechanism.