Combinations of metabolic syndrome components and the risk of type 2 diabetes mellitus: A nationwide cohort study

Objective: It remains unclear which specific combinations of metabolic syndrome (MetS) components confer a higher risk of type 2 diabetes mellitus (T2DM). This study examined the relation of each and combinations of MetS components with the risk of T2DM. Methods: We studied the records of 19,475,643 adults aged ≥ 20 years with no history of T2DM from the database of the Korean National Health Insurance Service covering 2009 to 2012. The hazard ratios (HRs) and confidence intervals (CIs) of T2DM were estimated using Cox proportional hazards models. Results: During a median follow-up of 5.13 years, 1,906,963 individuals were diagnosed with T2DM. The multivariable-adjusted HRs for T2DM were 1.86 for MetS, 1.821 for elevated fasting plasma glucose (FPG), 1.484 for elevated triglycerides, 1.415 for reduced high-density lipoprotein (HDL) cholesterol, 1.413 for elevated blood pressure (BP), and 1.17 for abdominal obesity compared with those without. In the combinations of two components excluding elevated FPG, subjects with elevated triglycerides and reduced HDL cholesterol had the highest risk of T2DM (HR 1.71; 95% CI, 1.695–1.725). In three components, the highest risk combination was elevated FPG, elevated triglycerides, and reduced HDL cholesterol (HR 3.342; 95% CI, 3.308–3.376). Conclusions: The combination of elevated triglycerides and reduced HDL cholesterol were more strongly associated with an increased risk of T2DM than other combinations except for elevated FPG.