People with diabetes may have an increased risk of developing cancer before and immediately after their diagnosis, a new study has found.

Previous research indicates that type 2 diabetes could increase the risk of developing a number of types of cancer, with the highest risk appearing to be soon after a diabetes diagnosis.

Canadian researchers decided to investigate this further. They looked at the incidence of cancer in over one million adults during different time points. They found that those with diabetes were 1.23 times - that is 123% - more likely to have been diagnosed with cancer during the 10 years before their diabetes diagnosis compared to people without diabetes.

"This supports existing hypotheses that shared risk factors may be contributing to both cancer and diabetes diagnoses," commented Dr Iliana Lega of the University of Toronto.

The study also found that the incidence of cancer was much higher among people with diabetes in the first three months after their diabetes diagnosis. However this increased risk did not appear to extend past three months.

"This may in part be explained by increased healthcare visits and screening tests following a diagnosis of diabetes," Dr Lega noted.

She warned that the increasing incidence of diabetes may lead to more cases of cancer as well.

"There is excellent evidence that diabetes can be prevented and that metabolic changes leading to diabetes can be reversed with lifestyle changes. Similarly, diet and exercise interventions have also been shown to reduce cancer risk and improve cancer outcomes in the general population.

"Our findings are important because they underscore the need for further research that examines the impact of exercise and healthy diet on cancer risk specifically in patients with, or at risk for, diabetes," she commented.

Details of these findings are published in the journal, CANCER.