Metabolic syndrome and all-cause mortality, cardiac events, and cardiovascular events: A follow-up study in 25,471 young- and middle-aged Japanese men

Aim: The association between subjects with metabolic syndrome (MS) who were considered not to require medication by their attending physicians and all-cause mortality, ischemic heart disease (IHD) and cardiovascular disease (CVD) remains unknown and should be clarified. Methods and results: This is an observational longitudinal cohort study with a median follow-up of 7.5 years performed for 25,471 Japanese men aged 20–61 years who were not on medication. We used a modified definition of MS from the Japanese Society of Internal Medicine and the NCEP ATPIII, both of which employed body mass index instead of waist circumference. MS was associated with increased rates of all-cause death (adjusted hazard ratio (HR): 4.88 [95% confidence interval, 2.96–7.66]), IHD (3.17 [1.06–7.65]), and CVD (2.63 [1.32–4.72]). In contrast, overweight subjects with no component or one component had similar rates to subjects of normal weight. Any combination of the three MS components was associated with significantly greater rates of all-cause mortality (HR: 3.18–11.2) and IHD (HR: 3.17–8.24), whereas blood pressure elevation plus dyslipidaemia was associated with a significantly higher rate of CVD (HR: 3.27). In any endpoint, MS defined by Japanese criteria had higher HRs than defined by NCEP ATP III criteria. Conclusion: Young and middle-aged Japanese men with MS who had been viewed as not needing medication already showed increased rates of all-cause mortality, IHD and CVD. Additionally, the event rate depended on the specific combination of metabolic syndrome components.