The extra risk of dying from diabetes has fallen hugely in the UK and Canada since the mid-1990s, according to a new study in the journal Diabetologia. The study shows that the gap in death risk between those with and without diabetes has narrowed substantially.
Authors Lorraine Lipscombe, an endocrinologist at Women’s College Hospital in Toronto, Canada, and Marcus Lind, of the University of Gothenburg in Sweden, and colleagues, estimated the current mortality rates in millions of patients with diabetes (both type 1 and type 2) compared to patients without diabetes and how they had changed over time.
A previous review had suggested having diabetes raised a person’s risk of death by 80% compared with the general population, but Lipscombe and colleagues say that review included many studies published before 2000: some more recent studies have suggested the figure is lower than this.
They estimated that from 1996 to 2009, the extra risk of dying because of having diabetes fell from 90% to 51% in Canada and from 114% to 65% in the UK.
The fall was across all age groups, for both men and women, and there was no significant difference between the sexes in 2009.
The excess risk of death for diabetic patients fell between 25% and 40% in those aged under 64 and between 50% and 65% in those aged 64 and over during the study period.
In 2009, for both the UK and Canada, the age group with the largest excess risk of dying because of diabetes were the 45- to 64-year-olds: their excess risk of death was double that of people without diabetes.
In 2009, the excess risk of death as a result of having diabetes for 20- to 44-year-olds was 70% to 80%, and for patients aged 65 and over it was 15 to 25%.
Although they did not examine the reasons for the large decrease in excess risk of death since the mid-1990s, the researchers suggest it is due to more aggressive treatment of diabetes and the conditions that lead to it, and improved screening that results in people with diabetes receiving treatment earlier.
The population figures they studied showed that in both countries the percentage of the adult population diagnosed with diabetes doubled: from 5.4% to 11.4% in Canada, and from 3.2% to 5.9% in the UK.
A 2012 report from the US Centers for Disease Control and Prevention shows a similar dramatic rise in diabetes rates in the US over a similar period.
In their review, Lipscombe and colleagues draw attention to the large difference in rates of diabetes between Canada and the UK. They didn’t investigate this, and said the reasons are unclear, but suggest differences in screening programs, ethnicity, and lifestyle may account for it.
Earlier this year, two studies led by Stanford University School of Medicine suggest that the genetic underpinnings of diabetes can vary based on ethnic background.
The reason the study confines itself to UK and Canada populations is because the authors in both these countries and Sweden are part of a group that is already studying these populations. Another reason is because these countries are among the few that have population databases with long follow-up which includes people with and without diabetes.
The figures included data on around 12.6 million people and came from the Ontario database in Canada and the The Health Improvement Network (THIN) in the UK.
In 2012, researchers in Sweden showed how a blood marker might reveal people at risk for type 2 diabetes many years before the disease is typically diagnosed.
Written by Catharine Paddock PhD