A 50-year-old with diabetes will die six years earlier than someone without the disease -- and not just from a heart attack or a stroke -- new research finds.

Doctors have long known that diabetes can shorten lifespan, but this study finds that the disease takes a toll on health that goes well beyond heart disease.

Not only is a diabetic more than twice as likely to die of heart disease as someone without diabetes, they're 25 per cent more likely to die of cancer, the study also found.

The biggest cancer risks were liver and pancreatic cancer and colorectal cancer.

Those with Type 2 diabetes are also more likely to die from kidney disease and liver disease, as well as infectious diseases. In a surprising finding, the suicide risk was also higher among diabetics.

The researchers conclude that diabetes shortens life, on average, by about six years. To put that in perspective, long-term smoking is thought to shorten life by about seven to 10 years.

The study was conducted by the Emerging Risk Factors Collaboration, at the University of Cambridge in England. The researchers looked at data on more than 820,000 people, most of them with Type 2, or adult-onset, diabetes. The findings are published in the New England Journal of Medicine.

The findings are worrisome, given that more than 9 million Canadians have diabetes or prediabetes, about 90 per cent of them with Type 2. The number of diabetics in Canada is expected to rise, as obesity rates climb and the population ages.

For this study, researchers reviewed almost 100 studies tracking diabetics. None of the study subjects had cardiovascular or other diseases at the beginning of the studies.

The participants were followed on average for 13.5 years, during which time more than 123,000 participants died. The researchers then crunched the numbers about how diabetes affected lifespan, taking into account such factors as age, gender and smoking.

The risk of death was only higher in those with poorly controlled diabetes. Those who kept their fasting glucose levels in the 70 to 100 mg/dL range did not have a significantly higher risk of death.

The study did not try to answer why death rates were higher among diabetics, but there could be a number of reasons for the findings.

While Type 2 diabetes starts in the pancreas, the disease takes a toll on many of the body's systems. High blood sugar can damage blood vessels, leading to heart disease in most patients.

The disease also weakens the immune system, perhaps putting patients at greater risk of infections and cancer. It can also cause nerve damage and eye damage, which may increase the risk of falls and accidents.

Dr. David M. Kendall, chief scientific and medical officer of the American Diabetes Association, who was not involved in the study, says too often, diabetes is not seen as a serious disease.

"Diabetes is often seen as a condition rather than an illness, something you can live with," Kendall told the L.A. Times.

"Well, in fact, this shows that it is associated with a significant risk of both morbidity and mortality."