Aims: We assessed whether the increased sequential changes in the fasting plasma glucose level (FPG) that is still within the normoglycemic range could be a predictor for future diabetes.
Methods: A prospective cohort study was conducted with 5296 male employees, aged 31-44 years. A sequential change in the FPG level was defined as the first follow-up FPG level minus the baseline FPG level. The incident diabetes was assessed at annual examinations during the next 4.1 years. Cox proportional hazard analyses were performed.
Results: During the 21,575.5 person-years follow-up among the 5,296 subjects, a total of 156 incident cases of type 2 diabetes occurred (116 cases among the 4,975 normoglycemic subjects and 40 cases among the 321 subjects with impaired fasting glucose). An increase in the FPG level from the baseline to the first follow-up, although still within the normoglycemic range (FPG<100 mg/dl), significantly predicted future diabetes: the multivariate hazard ratios associated with the sequential changes in the FPG of <-3, -3 to 3, 4-6, 7-9, and >9 mg/dl were 0.75, 1.00 (reference), 2.28, 3.28, and 6.10, respectively (p for trend <0.001).
Conclusions: The increase of the sequential changes in the FPG level that were within the normal glucose range was associated with a higher risk for developing diabetes. Thus, conducting assessment for the serial changes in the FPG level may help to identify the young, healthy, normoglycemic individuals at risk for type 2 diabetes.