Components of the metabolic syndrome as predictors of cardiovascular disease and type 2 diabetes in middle-aged Japanese men.

To determine whether the clustered features of the metabolic syndrome precede the 7 year incidence of cardiovascular disease (CVD) and type 2 diabetes, we examined 6182 Japanese male office workers aged 35-59 years without any history of CVD. The 5588 subjects without type 2 diabetes also constituted the nondiabetic cohort, and were re-examined over seven successive years. Components of the metabolic syndrome included glycemic disorder (type 2 diabetes for the risk of CVD and impaired fasting glucose for the risk of type 2 diabetes), systemic obesity, hypertension, dyslipidemia, proteinuria, and elevated white blood cell (WBC) count. After controlling for age, family history of diabetes, alcohol intake, and cigarette smoking, the multivariate-adjusted relative risk of incidence of CVD compared with absence of components was 3.18, 3.48, 12.55, and 14.15 (P for trend <0.001), for the presence of 1,2,3, and > or =4 components, respectively. The corresponding relative risks of incidence of type 2 diabetes were 1.92, 4.36, 6.44, and 15.08 (P for trend <0.001). In both non-smokers and current smokers, the multivariate-adjusted relative risks of incidence of CVD and type 2 diabetes increased as the number of components increased (P for trend <0.001 for all). Our findings indicate that clustered features of the metabolic syndrome are closely associated with development of CVD and type 2 diabetes in middle-aged Japanese.