Relationship between metabolic risk factor clustering and cardiovascular mortality stratified by high blood glucose and obesity: NIPPON DATA90, 1990-99

Abstract

Objective Metabolic syndrome (MS) is diagnosed according to several criteria. Among them, some require glucose intolerance and the others require obesity for diagnosing MS. We investigated the relationship between metabolic risk factor clustering and cardiovascular disease (CVD) mortality stratified by high blood glucose or obesity.

Research design and methods We followed 7,219 Japanese men and women without a history of CVD for 9.6 years. We defined high blood pressure, high blood glucose, high triglycerides, low high-density lipoprotein cholesterol and obesity as metabolic factors. The multivariate adjusted hazard ratio (HR) for CVD mortality according to the number of clustering metabolic factors was calculated using the Cox proportional hazards model.

Results During follow-up, 173 participants died of CVD. The numbers of metabolic risk factors and CVD mortality were positively correlated (P for trend = 0.07). The HR was obviously higher among participants with, than without high blood glucose and clustering of ≥2 other metabolic risk factors (HR = 3.67, CI, 1.49-9.03). However, the risk increase was only modest in participants without high blood glucose even if they had ≥2 other metabolic risk factors (HR = 1.99, CI, 0.93-4.28). Conversely, metabolic risk factor clustering was related to CVD mortality irrespective of obesity.

Conclusions Our findings suggest that glucose tolerance plays an important role in CVD mortality. Since the prevalence of non-obese participants with several metabolic risk factors was quite high and their CVD risk was high, excluding them from MS due to the absence of obesity might overlook their risk.