Link found between autoimmune diseases and heightened risk of dementia

Autoimmune diseases, such as multiple sclerosis and coeliac disease, may be linked to an increased risk of dementia, according to a new study.

Researchers from the University of Oxford analysed data of people admitted to hospitals in England for autoimmune diseases between 1998 and 2012 who were later admitted with dementia.

Of the 1.8m people admitted for an autoimmune disease, 81,502 later received a diagnosis of dementia.

Comparing this to data from a group of seven million people who were admitted to hospital over the same period for other causes, researchers found that those with an autoimmune disease were 20 per cent more likely to subsequently be admitted with dementia.

Dr Clare Walton, research manager at Alzheimer’s Society, said: “The causes of dementia are complex and we are increasingly learning about links between dementia and other health conditions.

'Other known factors can increase the risk more'

“This large scale study of UK hospital admissions data found that people with autoimmune diseases, such as multiple sclerosis or Crohn’s disease, have on average a 20 per cent increased risk of developing dementia.

“To put this in context, other known factors can increase a person’s risk of dementia much more – for example smoking by 45 per cent.”

She added that the new findings reinforce earlier evidence that the immune system plays an important role in dementia, which can open doors to finding effective treatments.

This is something Alzheimer’s Society is currently looking into by funding a study to test whether treatment for rheumatoid arthritis can also work for people in the early stages of Alzheimer’s.

This was one of the 25 autoimmune diseases covered in the study, along with coeliac disease, multiple sclerosis and ulcerative colitis.

Of these 25 diseases recorded, 18 were found to have a significant association with dementia.

Different risks for different types of dementia

Researchers analysed the type of dementia that patients developed and found that people previously admitted with an autoimmune disease had a 28 per cent increased risk of developing vascular dementia compared with a six per cent risk for Alzheimer’s disease.

Men with an autoimmune disease were also found to have a 32 per cent increased risk of developing dementia compared with 17 per cent for women, despite autoimmune diseases being more common in women than in men.

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: “We are becoming increasingly aware of the important role the immune system plays in dementia, and this new study provides evidence to support this link.

“As this study is observational and based only on hospital admission records, we cannot draw firm conclusions from its findings, but it supports ongoing work into the contribution of the immune system to dementia.

“There are 850,000 people living with dementia in the UK and there are as yet no treatments that can slow or stop damage to the brain in diseases like Alzheimer’s.

“Targeting immune and inflammatory responses is a promising approach for researchers working on new dementia treatments. Alzheimer’s Research UK is supporting projects that are designing new drugs that target different aspects of inflammation as a way to treat Alzheimer’s disease and other forms of dementia.”