Pre-impaired fasting glucose state is a risk factor for endothelial dysfunction: Flow-mediated Dilation Japan (FMD-J) study

INTRODUCTION: Diabetes mellitus is associated with endothelial dysfunction. However, there is little information on the relationships of fasting blood glucose (FBG), including high normal blood glucose and impaired fasting glucose (IFG) with endothelial function. The purpose of this study was to evaluate the relationship between FBG level and flow-mediated vasodilation (FMD) using a large sample size. RESEARCH DESIGN AND METHODS: This study was a cross-sectional study. We measured FMD in 7265 subjects at 31 general hospitals. The subjects were divided into four groups based on FBG levels: <100, 100–109, 110–125, and ≥126 mg/dL or known diabetes. The subjects were also divided into six groups based on FBG levels: <90, 90–94, 95–99, 100–109, 110–125, and ≥126 mg/dL or known diabetes. RESULTS: FMD decreased in relation to increase in FBG level. There was a significant difference in FMD between the FBG of <100 mg/dL group and the other three groups (6.7±3.1% vs 5.9±2.8%, 5.7±3.1%, and 5.1±2.6%, respectively; p<0.001). After adjustment for confounding factors, the odds of having the lowest quartile of FMD were significantly higher in the FBG of 95–99, 100–104, 105–109, 110–125, and ≥126 mg/dL or known diabetes groups than in the FBG of the <90 mg/dL group. CONCLUSIONS: These findings suggest that FBG of 100–109 mg/dL and FBG of 110–125 mg/dL are similarly associated with endothelial dysfunction and that a pre-IFG state (FBG of 95–99 mg/dL) is also a risk for endothelial dysfunction compared with FBG of <90 mg/dL. TRIAL REGISTRATION NUMBER: UMIN000012950, UMIN000012951, UMIN000012952, and UMIN000003409.