Despite Improvements, Diabetics Still Face Reduced Life Expectancy

In the last 50 years or so, medical advances have improved the life expectancy and quality of life of diabetics dramatically however they still face an increased risk of developing common chronic illnesses such as heart disease, stroke, and cancer. As a result of this, diabetics have a life expectancy around 8 years lower than their diabetic counter parts.

One of the largest studies on the impact of diabetes on life expectancy was published in the Archives of Internal Medicine, in 2007. The researchers used data from the Framingham Heart Study to determine the impact of diabetes on life expectancy at the age of 50. After adjusting the results for potential confounders such as BMI, smoking status, and physical activity, the researchers found that at 50, diabetic men could expect to live a further 21.3 years compared to 28.8 years for non-diabetic men. Diabetic women could expect to live a further 26.5 years compared to 34.7 years for non-diabetic women.

The biggest health issues faced by diabetics are an increased risk of cardiovascular diseases such as heart disease and strokes, an increased risk of certain forms of cancer, and a dramatically increased risk of kidney failure.

Cardiovascular disease

Diabetics have around a 40% increased risk of dying from cardiovascular disease compared to non-diabetics. Data from the INTERHEART study which involved almost 30,000 individuals from 52 countries calculated that diabetic men and women over 55 years of age were 1.93 and 2.59 times more likely to have a heart attack than non-diabetics. In diabetics aged 55 and under, the risks were even greater with women 3.53 and men 2.66 times more likely to have a heart attack than their non diabetic counterparts.

A study, conducted in 2006 and published in the British Medical Journal, reviewed the results of 37 previous studies and calculated the risk of fatal coronary heart disease to be 3.5 and 2.7 times greater in diabetic women and men respectively compared to non-diabetics.

Finally, data from the Nurses Health Study (NHS) suggests that the risk of stroke is increased by around 80% in diabetics. The risk appears to be elevated for ischemic stroke but not haemorrhagic stroke.

Cancer

Diabetics are around 5% more likely to develop cancer at a given age than non-diabetics. A large study of diabetes and cancer risk was published in the American Journal of Epidemiology in 2004. The main results of the study are presented in the graph below.

Graph of a diabetics risk of cancer

Diabetes was associated with a significant increase in the risk of liver, bladder, gallbladder, colon, endometrial, and pancreatic cancer. Interestingly, prostate cancer, kidney cancer, and leukaemia were all less likely in diabetics although none of these achieved statistical significance. Some other studies have suggested a link between diabetes and a decreased risk of prostate cancer, possibly as a result of decreased testosterone production in diabetics.

Kidney Failure

Kidney failure as a result of diabetes is known as diabetic nephropathy. Diabetics are four times more likely to die from kidney diseases than non-diabetics with between 8 and 10% of all diabetic deaths attributable to kidney failure. Diabetes can be incredibly taxing on the kidneys, particularly if blood glucose levels go uncontrolled for many years. Keeping both blood glucose and blood pressure levels in a normal range can dramatically reduce a diabetics risk of having kidney problems later in life.