Non-cardiovascular Calcification Measures and Warranty Period of a Zero CAC in Young Adults: the Multi-ethnic Study of Atherosclerosis

Rationale and Objectives: This study investigates the warranty period for downstream incident coronary artery calcium (CAC) > 0 and cardiovascular disease (CVD) events in young adults (age < 50 years) with baseline CAC = 0, stratified by non-cardiovascular calcification. The absence of coronary calcification (CAC = 0) is a strong negative risk predictor, especially in young, low-risk individuals, as coronary events without CAC are rare. Beyond known cardiovascular risk factors, propensity for systemic calcium deposition—reflected by non-cardiovascular calcification—may influence incident CAC > 0. Refining risk prediction in young adults, who face cumulative harms from unnecessary imaging and radiation, is important. Materials and Methods: Young adults with baseline CAC score = 0 from Exam 1 (2000–2002) of the MESA cohort (n = 402) were stratified by costal cartilage calcification (CCC) into below- and above-median groups (n = 201 each). A Weibull parametric survival model estimated time-to-conversion to CAC > 0 and CVD events, enabling estimation of the “warranty period” as the mean time to 25% incidence of CAC > 0% and 2% incidence of CVD events. Results: By Exam 5 (2010–2012), incident CAC > 0 was observed in 27% of the below-median group and 42% of the above-median group. The warranty period for 25% CAC > 0 incidence was shorter in the above-median group (8.0 [95% CI: 7.2, 8.7] vs. 9.6 [8.6, 10.6] years). Conversely, the warranty period for 2% CVD incidence was longer in the above-median group (11.2 [95% CI: 7.4, 18.1] vs. 9.3 [95% CI: 6.5, 14.1] years). Conclusion: In young adults with CAC = 0 at baseline, high non-cardiovascular calcification may indicate a shorter CAC > 0 incidence warranty period and possibly less severe atherosclerotic stages, as reflected by a longer warranty period for CVD events.