Having diabetes in mid-life can reduce a person’s life expectancy by six years, a study has found.

Diabetes is already known to approximately double the risk of heart attacks and strokes.

However, the new findings show that people with Type 2 diabetes are also at greater risk of dying from several other diseases, including cancer and infection.

Scientists from the Emerging Risk Factors Collaboration – co-ordinated by the University of Cambridge – analysed data on 820,900 people, each of whom was monitored for about a decade.

After accounting for other major risk factors such as age, sex, obesity and smoking, they found that people with diabetes are at increased risk of death from several common cancers, infections, mental disorders, and liver, digestive, kidney and lung diseases.

About 60 per cent of the reduced life expectancy in people with diabetes is attributable to blood vessel diseases (such as heart attacks and strokes), with the remainder attributable to these other conditions, the report said.

Researchers said the findings highlight the importance of preventing diabetes, which affects nearly 285 million people worldwide.

John Danesh, professor and principal investigator of the study, from the University of Cambridge, said: “These findings broaden and intensify the need for efforts to prevent and understand diabetes.

“In particular, the findings highlight the need for more detailed study of whether treatments against diabetes may also be relevant to lowering the risk of a range of diseases, including common cancers.”

The study was funded by the Medical Research Council.

Naveed Sattar, professor at the University of Glasgow, was involved as one of the authors of the paper.

He said: “Overall, the findings should help incentivise diabetes prevention in those at high risk.

“There is also some good news here. We show that a halving of the risk of death in patients with diabetes compared to those without, over the last four decades, is a trend almost certainly linked to better treatments in diabetes patients.”

The collaborative study, which involved more than 250 scientists from 25 countries, also suggests that people with diabetes may be at increased risk of death from intentional self-harm – a finding which the scientists say requires further study, including investigation of the possible link between diabetes and depression.