An international team, writing in the British Journal of Cancer, examined 40 separate studies to determine whether there was a direct link between breast cancer and diabetes, the BBC News reported.
The studies which involved more than 56,000 women with breast cancer found that post-menopausal women with Type 2 diabetes had a 27 per cent increased risk of the disease.
However, there was no link for pre-menopausal women or those with Type 1 diabetes.
A high body mass index (BMI), which is often associated with diabetes, may be an underlying contributing factor, authors have suggested.
"We don't yet know the mechanisms behind why Type 2 diabetes might increase the risk of breast cancer," Professor Peter Boyle, president of the International Prevention Research Institute, who led the study, said.
"On the one hand, it's thought that being overweight, often associated with Type 2 diabetes, and the effect this has on hormone activity may be partly responsible for the processes that lead to cancer growth," Boyle said.