People with the common arthritic disease, gout, may have a reduced risk of developing Alzheimer's disease, a new study has found.

Gout is the most common type of inflammatory arthritis. It causes sudden and severe episodes of joint pain, swelling, tenderness and warmth. It most commonly affects the joint at the base of the big toe, but other joints can also be affected, such as the knees, ankles and wrists.

It is caused by a build-up of uric acid in the blood, which can sometimes be caused by a diet high in protein and alcohol.

Studies have linked the condition to an increased risk of kidney and heart problems, but they have also suggested that the antioxidant properties of uric acid may protect against certain neurological conditions, such as Parkinson's disease.

US researchers decided to investigate whether gout offered any protective effects when it came to the development of Alzheimer's disease. Using a UK medical database, they analysed the medical records of 3.7 million people aged 40 and older.

The study found that people with a history of gout had a 24% reduced risk of developing Alzheimer's disease. The results stood even when other factors were taken into account such as age, body mass index (BMI) and prior heart conditions.

The researchers suggest that uric acid may offer a protective effect for the brain.

"Our findings provide the first population-based evidence for the potential protective effect of gout on the risk of Alzheimers' disease and support the purported neuroprotective role of uric acid," the team from Harvard Medical School said.

Details of these findings are published in the journal, Annals of the Rheumatic Diseases.

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