Age-stratified effects of coronary artery calcification on cardiovascular and non-cardiovascular mortality in Korean adults

AIMS: The role of coronary artery calcium score (CACS) in predicting cardiovascular disease (CVD) and non-CVD mortality in young adults is unclear. We investigated the association of CACS with CVD and non-CVD mortality in young and older individuals. METHODS AND RESULTS: CVD-free Koreans (n = 160 821; mean age, 41.4 years; 73.2% young individuals aged <45 years) who underwent cardiac tomography estimation of CACS (69.7% one-time measurement), were followed-up for a median of 5.6 years. The vital status and cause of death were ascertained from the national death records. Sub-distribution hazard ratios (SHR) and 95% confidence intervals (CIs) for cause-specific mortality were estimated using the Fine and Gray proportional hazards models. Overall, a higher CACS was strongly associated with an increased risk of CVD mortality. Among young individuals, multivariable-adjusted SHR (95% CIs) for CVD mortality comparing a CACS of 1-100, 101-300, and >300 to 0 CACS were 5.67 (2.33-13.78), 22.34 (5.72-87.19), and 74.1 (18.98-239.3), respectively, and among older individuals, corresponding SHR were 1.51 (0.60-3.84), 8.57 (3.05-24.06), and 6.41 (1.98-20.74). The addition of CACS to Framingham risk score significantly but modestly improved risk prediction for CVD mortality in young individuals. Conversely, CACS was significantly associated with non-CVD mortality only in older individuals. CONCLUSIONS: Strong associations of CACS with CVD mortality, but not non-CVD mortality, were observed in young individuals, beginning in the low CACS category. Our findings reaffirm the need for early intervention for young adults even with low CACS to reduce CVD mortality.