AIMS As lifetime accumulation of cardiovascular risk factors is gaining importance, early identification and management of risk factors are being emphasized. The global prevalence of metabolic syndrome (MetS), a constellation of these risk factors, is increasing, particularly among young adults. In this study, we aim to investigate the association between cumulative exposure to metabolic risk and cardiovascular disease (CVD) in young adults.

METHODS AND RESULTS In this nationwide population-based cohort, we analysed 3 688 787 young adults (<40 years) with 2 biennial National Health Screening examinations from 2009 to 2012. Participants were categorized into MetS-free, MetS-developed, MetS-recovered, or MetS-persistent group, based on MetS presence at each examination. The endpoint was new CVD development, including myocardial infarction (MI) and ischaemic stroke. During follow-up (median, 7.7 years), CVD occurred in 19 219 individuals (0.5%). The incidence rates of CVD were 0.58, 1.17, 1.20, and 1.83 (1000 person-years) in the MetS-free, MetS-developed, MetS-recovered, and MetS-persistent groups, respectively. The CVD risk was proportionally associated with cumulative metabolic risk exposure, with a maximum two-fold increase in the MetS-persistent group [adjusted hazard ratio (aHR) 1.94, 95% confidence interval (CI) 1.84-2.04], followed by the MetS-recovered and the MetS-developed groups with similar risks. Among the MetS components, persistent exposure to elevated blood pressure (BP) had the greatest association with CVD risk (aHR 1.69, 95% CI 1.63-1.76). This tendency was consistent in the separate analyses of the risk of MI and ischaemic stroke.

CONCLUSION The risk of CVD increased in an exposure-dependent manner among young adults. Efforts to optimize the cardiometabolic profile, particularly BP, even after the establishment of MetS, might help promote long-term cardiovascular prognosis.