Independent association between age- and sex-specific metabolic syndrome severity score and cardiovascular disease and mortality

Traditional metabolic syndrome (MetS) criteria have several limitations, which hinder its use in clinical practice. To overcome the limitations, we investigated the association between age- and sex-specific continuous MetS severity score (cMetS-S) and cardiovascular disease (CVD) and mortality beyond MetS components in the framework of the Tehran Lipid and Glucose Study. Participants aged 20–60 years at baseline were included in the study. We excluded participants with CVD, cancer, use of corticosteroids, estimated glomerular filtration rate < 30 ml/min/1.73 m(2), and those who were pregnant. We evaluated the association between cMetS-S with CVD and mortality over 18 years of follow-up among 8500 participants with continuous and quantile approaches using the Cox proportional hazard regression model. In addition, the model performance of cMetS-S for predicting CVD events was compared to the conventional MetS criteria. Participants with higher cMetS-S had a significantly increased risk for CVD, coronary (CHD) and non-coronary heart disease (non-CHD), and all-cause, cardiovascular, and sudden cardiac death. Independent of the confounders and MetS components, the cMetS-S had the HRs of 1.67 (95% CI 1.47–1.89), 1.60 (95% CI 1.37–1.86), and 1.88 (95% CI 1.50, 2.35) for CVD, CHD, and non-CHD events upon 1-SD increment, respectively. The risk of mortality was increased for 1-SD of cMetS-S (all-cause mortality, HR 1.24; 95% CI 1.09–1.41; CVD mortality, HR 1.72; 95% CI 1.20–2.45; sudden cardiac death, HR 1.60; 95% CI 1.03–2.49). The model fitness of cMetS-S was superior to the conventional MetS criteria in predicting CVD and mortality. The cMetS-S provided an additional risk for CVD and mortality beyond the individual MetS components. Standardized cMetS-S could be a potential universal measure to define MetS severity while considering the weighted contribution of MetS components and their variations by age, sex, and ethnicity.