Risk factors associated with the incidence and progression of mitral annulus calcification: the multi-ethnic study of atherosclerosis.

BACKGROUND: Significant cardiovascular morbidity has been associated with mitral annulus calcification (MAC), but limited data exist regarding its progression. The purpose of this study was to examine the natural history of and risk factors for MAC progression.
METHODS: The MESA is a longitudinal cohort study of participants aged 45 to 84 years without clinical cardiovascular disease who underwent serial cardiac computed tomography studies with quantification of MAC. Regression models were used to identify risk factors associated with MAC incidence and progression.
RESULTS: Prevalent MAC was observed in 534 (9%) of 5,895 participants. Over a median 2.3 years, 280 (5%) developed incident MAC. After adjustment, age was the strongest predictor of incident MAC (adjusted OR, 2.25 per 10 years; 95% CI, 1.97-2.58; P < .0001). Female gender, white ethnicity, body mass index, diabetes, hypertension, hyperlipidemia, serum cholesterol, smoking, and interleukin-6 were also significant predictors of incident MAC. In participants with prevalent MAC, the median rate of change was 10.1 [IQR, -6.7 to 60.7] Agatston units (AU)/year. Baseline MAC severity was the predominant predictor of rate of MAC progression (β-coefficient per 10 AU, 0.88; 95% CI, 0.85-0.91; P < .0001), although ethnicity and smoking status possessed modest influence.
CONCLUSIONS: Several cardiovascular risk factors predicted incident MAC, as did female gender. Severity of baseline MAC was the primary predictor of MAC progression, suggesting that, while atherosclerotic processes may initiate MAC, they are only modestly associated with its progression over these time frames.