Relationship of moderate metabolic risk factor clustering to cardiovascular disease mortality in non-lean Japanese: A 15-year follow-up of NIPPON DATA90

Objective: The individual components of metabolic syndrome are defined as levels ranging from moderate to high level as to require medication. We investigated the impact of moderate metabolic risk factor clustering on cardiovascular disease (CVD) mortality. Methods: We followed up 6758 non-lean Japanese in randomly selected areas from all over the country who had no history of CVD for 15 years. The multivariate-adjusted hazards ratio (HR) and 95% confidence interval (CI) for CVD mortality according to the number of moderate metabolic risk factors (BMI≥25kg/m², 130/85mmHg≤systolic/diastolic BP<140/90mmHg, 140mg/dl≤casual blood glucose<200mg/dl, triglycerides≥150mg/dl and/or HDL cholesterol<40mg/dl [men], 50mg/dl [women]) were estimated using the Cox proportional hazards model. The population-attributable risk fraction of moderate metabolic risk factor clustering was also estimated. Results: During the follow-up, 282 participants died of CVD. CVD mortality tended to increase with the number of moderate metabolic risk factors. However, they were not statistically significant. The multivariate-adjusted HRs were 1.82 (95%CI: 0.89-3.73) for having any moderate metabolic risk factors and 2.87 (95%CI: 1.46-5.64) for having any medication-required metabolic risk factors, compared with participants without any moderate metabolic risk factors. The population-attributable risk fractions were 7.3% and 52.4% for any moderate and medication-required metabolic risk factors, respectively. Conclusions: We did not find the statistically significant increase of CVD mortality for moderate metabolic risk factor clustering. Its attribution was relatively small in this Japanese population. More efforts would be required to detect and control medication-required risk factors.