Does cancer risk increase with HbA 1c, independent of diabetes?

Background: The risks for several cancer types are increased in people with diabetes. Hyperglycaemia, hyperinsulinaemia, inflammation and altered hormonal concentrations are common characteristics between the two diseases and can all be linked to hyperglycaemia. Methods: Here, we use glycated haemoglobin (HbA_1c) as a biomarker for chronic hyperglycaemia. We explore whether cancer risk increases with HbA 1c, independent of diabetes, and, therefore, if risk is already increased below the diabetic HbA 1c range, by analysing data from current studies linking HbA 1c to risk of several cancer types. Results: The data reveal that chronic hyperglycaemia correlates with increased cancer risk for a number of cancers, except prostate cancer. Evidence is also provided that risk is already increased in the pre-diabetic and normal ranges for several cancers. Conclusions: These results merit urgent investigation into the risks and advantages of updating recommendations for stricter glycaemic control in diabetic and non-diabetic subjects, as this could help reduce the risk of cancer incidence and mortality.