« Back to News

07.01.15

Scottish Study Finds Improvement in Life Expectancy for Patients with Type 1 Diabetes

A major study of patients in Scotland living with type 1 diabetes has found life expectancy has improved in comparison to previous research, although it still lags significantly behind that of the general population without diabetes.

The study carried out by researchers at the University of Dundee and the Scottish Diabetes Research Network shows that type 1 diabetes is associated with on average a reduction in life expectancy of about 11 years in men and about 13 years in women compared with the general Scottish population without type 1 diabetes.

Researchers said their data indicated an improvement on historical reports but also emphasised the need for further improvement in life expectancy in type 1 diabetes.

The results of the study are published in the January 6th issue of JAMA, the Journal of the American Medical Association.

Diabetes charities such as Diabetes UK and the Juvenile Diabetes Research Foundation cite losses of life expectancy of between 15 and 20 years. Estimates from the United States in the 1970s reported a loss of 27 years, while a New Zealand study in the 1980s found a loss of 16.5 years.

Major advances in treatment of type 1 diabetes have occurred in the past three decades. Accurate contemporary estimates of life expectancy would be useful as a measure of the current effect of diabetes and as a benchmark for assessing changes in diabetes care through time as well as being useful in the setting of insurance premiums.  However, although there are many reports regarding death rates for type 1 diabetes, few studies have provided life expectancy data.

Professor Helen Colhoun and Shona Livingstone at University of Dundee and colleagues in the Scottish Diabetes Research Network used a large national registry of patients with type 1 diabetes living in Scotland to provide contemporary comparisons of life expectancy with the general population without the disease. The analysis included individuals who were 20 years of age or older from 2008 through 2010 (n = 24,691) with type 1 diabetes.

Life expectancy at an attained age of 20 years was an additional 46.2 years among men with type 1 diabetes and 57.3 years among men without it, an estimated loss in life expectancy with diabetes of 11.1 years. Life expectancy from age 20 years was an additional 48.1 years among women with type 1 diabetes and 61.0 years among women without it, an estimated loss with diabetes of 12.9 years. In the general population without type 1 diabetes, 76 percent of men and 83 percent of women survived to age 70 years compared with 47 percent of men and 55 percent of women with type 1 diabetes.

Overall, the largest percentage of the estimated loss in life expectancy was related to ischemic heart disease, but death from diabetic coma or the condition ketoacidosis was associated with the largest percentage of the estimated loss occurring before age 50 years.

Kidney disease in diabetes was shown to be an important contributor to the reduced life span.  However it is not the only cause - even among patients with type 1 diabetes and preserved kidney function, life expectancy was reduced, with an estimated loss from age 20 years of 8.3 years for men and 7.9 years for women.