Drugs used to treat rheumatoid arthritis could halve the risk of patients developing dementia, a study suggests.
Researchers at the University of Oxford analysed the records of more than 5800 people living with the condition across the UK.
They compared 3876 patients who took disease-modifying anti-rheumatic drugs (DMARDs), particularly methotrexate, with 1938 patients who did not.
The findings, published in the journal Alzheimer's And Dementia: Translational Research And Clinical Interventions, found those on the anti-inflammatory medication had approximately half the risk of developing Alzheimer's disease and other forms of dementia.
"This study shows a positive link between patients taking drugs to treat arthritis and reducing their risk of developing dementia - potentially by up to 50 per cent," said lead researcher Professor Chris Edwards, of the NIHR Southampton Biomedical Research Centre.
Currently there is medication available that can temporarily reduce some symptoms or slow down the progression of Alzheimer's disease but there is no cure for the condition.
"The results we've seen make us optimistic that we are getting closer to better treating this neurological disease and supports further investigation in clinical trials to confirm if these drugs can be used to prevent or treat dementia," said Professor Edwards.
Rheumatoid arthritis is a long-term condition that causes pain, swelling and stiffness in the joints.
It develops when the immune system attacks the cells that line the joints and can also affect other parts of the body, including the lungs, heart and eyes.
The inflammation it causes is a characteristic feature of many other conditions, including dementia
It's thought drugs used to treat the inflammation caused by rheumatoid arthritis may also be beneficial for patients with other diseases.
"This has already been shown to be the case for treating patients with heart disease, where initial promising results are now being further investigated in large clinical trials," said Professor Edwards.