The largest ever study of diabetes prevalence in Australia has found that rates have increased in recent years, with more than one in ten people over the age of 45 affected.

Results from the EXTEND45 (EXamining ouTcomEs in chroNic Disease in the 45 and Up ) Study, based on laboratory and healthcare records for more than 152,000 people in NSW, show a prevalence of diabetes of 10.8%.

And the data, derived from the 45 and Up Study of patients that started in 2006-2009, showed a further 5.9% of the study population developed incident diabetes during seven to ten years of follow up, according to researchers from George Institute for Global Health, Sydney.

This represented a diabetes incidence rate of 10 per 1000 person years overall, with men showing a higher incidence than women (12.7 vs 8.0 per 1000 person years). Diabetes incidence rates were highest in the 65-74 year age group at 13.6 per 1000 person years.

Previously identified modifiable variables for development of diabetes, such as BMI, smoking and excessive sleeping time, were confirmed in the study, as well as non-modifiable factors such as family history of diabetes and being born overseas.

According to the study investigators, EXTEND45 is the largest population-based cohort study of diabetes prevalence in Australia, and the rates are significantly higher than those reported in earlier studies such as the 8.8% estimated in the Blue Mountains Eye Study of 20 years ago.

The 10.8% diabetes prevalence is also higher than the 7.4%  rate reported in the earlier AusDiab  Study and the 9.2% rate in the ABS 2007-08 National Health Survey.

The authors said some of the difference in prevalence may be due to wider age ranges in previous studies, different diabetes criteria and reliance on self-reports of diabetes status. Despite these variables, they said the latest estimate “may reflect true increases in diabetes prevalence over time”.

They also noted that the incidence rates for diabetes appeared constant at 1% a year over time, despite the introduction of prevention initiatives.

“The prevalence of diabetes is increasing in Australia, associated with rapid lifestyle changes and  improvements in  healthcare,” they concluded.

“Large real-world linked datasets such as the EXTEND45 Study will be useful for efficiently examining how diabetes prevention initiatives affect its burden over time.”

The findings are published in the Journal of Clinical and Translational Endocrinology.