<qa>  What is the HbA1C?We use the measurement of HbA1C as an additional index for diabetes. The Expert Committee On The Diagnosis And Classification Of Diabetes Mellitus did not include HbA1C as one of the criteria of diabetes because of difficulties in standardizing reference ranges of such a measurement across laboratories. This is much less a concern in this study since all procedures will be performed in the same laboratory, and the results are used for research rather than clinical purposes. The addition of the HbA1C affords us with information on glycemic levels in a time scale of weeks, whereas plasma glucose varies greatly within any given day and from day to day. Thus, an elevated HbA1C indicates a chronic state of hyperglycemia while hyperglycemia as measured by the FPG or 2-h PG may be transitory. 