Coronary artery calcium incidence and changes using direct plaque measurements: The MASALA study

Background and aims: We aimed to identify predictors of change in direct measures of coronary artery calcium (CAC) volume and density in South Asian participants. Methods: We used data from participants in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study with prevalent CAC and direct measures of CAC by serial computed tomography (CT) exams (2010–2013, 2016–2018). We examined the distribution of incident CAC volume and peak density, as well as progression and identified risk factors for progression of change in volume and density in multivariable models. Results: The study cohort consisted of 102 participants with incident CAC and 285 with CAC progression. CAC volume and density were highest, and incident CAC was most common in the left anterior descending artery (LAD). The greatest progression in volume was in the right coronary artery and the greatest change in density was in the left main. In linear regression models for CAC progression adjusted for baseline density, volume, risk factors, smoking (β +190.1, p = 0.02), baseline volume (β +0.24 per mm³, p < 0.01), and scan interval (β +0.15 per day, p = 0.01) were associated with change in total volume whereas Lp(a) (β +0.81 per mg/dL, p = 0.03), exercise (β +0.19 per 10 MET-min/week, p = 0.01), and baseline volume (β +0.15 per mm³, p < 0.01) and density (β −0.55 per unit, p < 0.01) were associated with change in total density. Conclusions: In this South Asian cohort, smoking was associated with CAC volume progression, while Lp(a) and exercise were associated with progression of peak CAC density.