Impact of coronary artery calcium on mortality and cardiovascular events in metabolic syndrome and diabetes among younger adults

AIMS: Whether coronary artery calcium (CAC) testing in younger individuals with metabolic syndrome (MetS) and diabetes mellitus (DM) helps predict cardiovascular disease (CVD) and death independent of traditional risk factors (RFs) remains less clear. METHODS AND RESULTS: We pooled data obtained from 5174 individuals aged 38-55 years from the CARDIA (Coronary Artery Risk Development in Young Adults; n = 3047, year 20) and MESA (Multi-Ethnic Study of Atherosclerosis; n = 2127, Visit 1) studies who completed computed tomography of CAC. The mean age (SD) of participants (44.7% men) was 47.3 (4.2) years. Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HRs) of CVD, coronary heart disease (CHD), and all-cause death. There were 1085 participants (21.0%) with prevalent CAC at baseline. A total of 461 (8.9%) had DM, 1025 (19.8%) had MetS without DM, and 3688 (71.3%) had neither condition. Over a median follow-up of 14.2 years, 256 (5.0%) participants died, and 304 (5.9%) CVD and 188 (3.6%) CHD events occurred. The CAC score was independently associated with incident CVD in those with DM (HR: 95% CI; 1.22: 1.08-1.38), MetS (1.18: 1.08-1.31), and neither condition (1.36: 1.26-1.46). The corresponding HRs for CAC ≥ 100 were 2.70 (1.25-5.83), 3.29 (1.87-5.79), and 6.30 (4.02-9.86), respectively. Similar associations for CHD and death were found. The impact of CAC ≥ 100 on CVD and CHD was lower in the presence of DM (P interaction < 0.05). The association of CAC with all outcomes in individuals with DM remained significant after adjusting with haemoglobin A1c levels. CONCLUSION: Coronary artery calcium score is independently associated with cardiovascular events and death over nearly 15 years after screening at ages 38-55 years, with a less pronounced impact on CVD and CHD events in the presence of DM.