THE EFFECTS OF AGING ON GLYCATION AND THE INTERPRETATION OF GLYCEMIC CONTROL IN TYPE-2 DIABETES

To investigate the discrepancy in the assessment of glycaemic control using glycated haemoglobin (HbA(1C)) and glycated proteins (fructosami ne), the effect of age on these variables was measured in non-diabetic individuals. In 232 non-diabetics, there was a linear relationship be tween HbA(1C) and age (r=0.49, p<0.0001). Mean HbA(1C) rose from 3.82% to 4.44% between the ages of 20 and 70. Consequently, when Type 2 dia betic patient samples (n=128, median age 63 years) were classified acc ording to European guidelines into good or poor glycaemic control usin g both an age-matched (n=101) and a younger (n=108, median age 37 year s) non-diabetic reference population, fewer patients were in good cont rol (14% vs. 25%) and more in poop control (73% vs. 53%) when the youn ger reference population was used (both p<0.05). In a subgroup of 126 non-diabetic subjects, HbA(1C) rose with age (r=0.48), but serum fruct osamine and fasting glucose did not (r=0.07, r=0.009, respectively, p= NS). Age-associated differences in nondiabetic HbA(1C) values may affe ct the assessment of glycaemic control in diabetic patients. It may al so partly explain discrepancies found when comparing fructosamine with HbA(1C) as a measure of glucose control. Age-related HbA(1C) referenc e intervals may therefore be required for the treatment of patients an d the accurate auditing of clinic performance.