2009 Volume 48 Issue 6 Pages 401-409
Objective To find useful indices to identify subjects at high risk for developing diabetes.
Methods We retrospectively reviewed 75-g oral glucose tolerance test (OGTT) surveys conducted during 1980 to 2001 in a Japanese community. Using personal charts of the surveys, 230 non-diabetics were followed for progression to type 2 diabetes. The usefulness of HbA1C, fasting (Glucose0) and 1-hour (Glucose60) glucose levels during OGTT, and indices for insulin resistance and/or secretion to identify high risk subjects for diabetes were then analyzed.
Materials Data described in personal charts of the OGTT program for residents of Nishikawa Town, Niigata Prefecture, Japan.
Results During the 4.3±2.7 years of follow-up, 52 subjects progressed to type 2 diabetes. Assessing glucose and insulin levels during OGTT, Glucose0, Glucose60, "Insulin Response Ratio" (IRR30, Insulin at 30 minutes / Fasting insulin; IRR60, insulin at 60 minutes / fasting insulin), and insulin secretion / insulin resistance index (ISIRI30) were significantly associated with progression to type 2 diabetes even after the result for OGTT, body mass index, and familial history of diabetes were adjusted. These were also able to identify still higher risk subjects for type 2 diabetes from those with impaired glucose tolerance (IGT) although other indices for insulin resistance or secretion and hemoglobin A1C were less contributable for this purpose.
Conclusion A combination of Glucose0 and Glucose60 can most cost effectively identify high risk subjects for type 2 diabetes from IGT. IRR30, IRR60 and ISIRI30 can also be used for such identification. However, further studies are needed to clarify whether these indices are superior to Glucose0 and Glucose60.