Increased Mortality Risks of Pre-Diabetes (Impaired Fasting Glucose) in Taiwan

Abstract

OBJECTIVE—The objective of this article was to assess mortality risks at different levels of fasting blood glucose (FBG) in Taiwan, with particular attention to those pre-diabetic subjects with impaired fasting glucose (IFG). RESEARCH DESIGN AND METHODS—Governmental employees and schoolteachers were followed up for an average of 11 years. With the use of Cox regression analyses, mortality risks were calculated for 36,386 subjects, aged 40–69. RESULTS—FBG ≥110 mg/dl was associated with increased mortality risks for all causes, cardiovascular diseases (CVD), and diabetes. IFG, when defined as 110–125 mg/dl, was associated with a significant increase for CVD and/or diabetes mortality. These mortality risks remained elevated when known CVD risk factors were adjusted for. The IFG group shared risk factor characteristics more with the FBG ≥126 mg/dl group than with the FBG <110 mg/dl group. When IFG was defined as 100–125 mg/dl, the number of subjects quadrupled, but mortality risks diminished substantially because of the inclusion of 100–109 mg/dl group. The lowest FBG group, 50–75 mg/dl, had a significant 2-fold risk from all causes. CONCLUSIONS—There was an overall J-shaped relationship between all-cause mortality and FBG. IFG, when defined as 110–125 mg/dl, is an independent risk factor and should be aggressively treated as a disease because its subsequent mortality risks for CVD and diabetes were significantly increased. The newly defined IFG at 100–125 mg/dl did not have the predictive power for later increases in CVD or diabetes mortality.