High levels of HbA1c within normal range predict future diabetes
MedWire News: Levels of glycated hemoglobin (HbA1c) at the upper end of the normal range significantly predict Type 2 diabetes, report researchers.
The American Diabetes Association has recently recommended the use of an HbA1c cutpoint of 6.5% for diagnosis of Type 2 diabetes, but less is known about how variation within the normal range of values for HbA1c can impact future diabetes risk.
Enzo Bonora (University of Verona, Italy) and co-workers measured HbA1c levels in 919 Caucasian men and women without Type 2 diabetes, who were aged 40-79 years. The participants were then followed up for 15 years for incidence of Type 2 diabetes.
When categorized according to their baseline levels of HbA1c, namely, less than 5.00%, 5.00-5.49% (reference group), 5.50-5.99%, and 6.00-6.49%, 15-year risks for developing Type 2 diabetes were negligible in the less than 5.00% group versus the reference group.
However, the risk was significantly increased by 3.79- and 12.50-fold in the 5.50-5.99% and 6.00-6.49% groups, respectively, compared with the reference group.
Of note, adjustment for several possible confounding factors such as lipid levels, a family history of diabetes, alcohol use, and physical activity did not significantly alter the results.
"The findings of the current study confirm a progressively increased risk of Type 2 diabetes across categories of HbA1c and clearly document that subjects with high-normal HbA1c have a strong risk of developing Type 2 diabetes," write Bonora et al in the journal Diabetes Care.
"Specific intervention trials, however, are needed to confirm such a conclusion because those conducted so far, based on lifestyle changes and/or drug use, recruited subjects at risk according to their plasma glucose levels and not HbA1c," they conclude.
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By Helen Albert