People who suffer autoimmune diseases such as multiple sclerosis (MS) may have an elevated risk of developing dementia, a new study suggests.
There are more than 80 different types of autoimmune disease, from multiple sclerosis and type 1 diabetes and rheumatoid arthritis.
These conditions are illnesses or disorders that occur when healthy cells get attacked by the body's immune system.
It has been suggested autoimmune and inflammatory activity may have a role in the development of dementia.
In a bid to investigate, the researchers from the University of Oxford, examined 25 different autoimmune diseases.
Of these, 18 showed significant positive associations with dementia, according to the study published in the Journal Of Epidemiology And Community Health.
The authors drew information on hospital admissions data between 1998 to 2012 for England.
Overall people admitted to hospital with an autoimmune disease were 20 per cent more likely to have a subsequent admission for dementia than those without an admission for an autoimmune disease.
The researchers emphasise the size of the associations they found was small, so further research would be needed to confirm or refute the findings.
"Our findings should be considered as indicative rather than definitive," the authors caution.
But they added: "People admitted to hospital with an autoimmune disease, likely to be those at the severe end of the disease spectrum, do appear to have an elevated risk of dementia.
"This finding is consistent with autoimmune disease predisposing to vascular risk and vascular dementia.
"It is also, separately, consistent with the theory that Alzheimer's disease may have an autoimmune component."
