HbA1c levels rise rapidly in the year before a diagnosis of type 2 diabetes, say Japanese researchers.
Their study looked at 1,722 individuals aged 26–80 years without diabetes and measured fasting plasma glucose and HbA1c were measured annually for a mean of 9.5 years.
A diagnosis of diabetes was given to 193 people, who had a mean HbA1c level of over 38mmol/mol (5.6%) each year before diagnosis.
Average blood glucose and HbA1c values throughout the observational period were significantly higher in incident cases compared with non-cases, with differences of 1.02 mmol/L and 18 mmol/mol (0.471%) higher, respectively.
In the entire group, marked increases in HbA1c of 20 mmol/mol (0.3%) per year and fasting plasma glucose of 0.63 mmol/L/year predicted a diagnosis of diabetes.
Professor Hirohito Sone, diabetologist at the University of Tsukuba Institute of Clinical Medicine, Tsukuba, Japan, said their findings showed the value of screening regularly in those at risk of diabetes.
He said: ‘To confirm our findings, further investigations are needed that include participants of other ethnicities.'
Diabetes Care 2012, online 28 March 2012