Urate's protective role in brain cells could affect the likelihood of Parkinson's disease in men.
Parkinson's disease is a motor system disorder that usually appears in people aged over 60 years. It results from the loss of dopamine-producing brain cells.
The main symptoms are tremor or trembling, rigidity or stiffness of the limbs and body, slowness of movement and impaired balance and coordination. Symptoms start gradually but worsen over time, making it difficult to carry out everyday tasks.
There is currently no cure, but treatments can be given that replace or mimic the role of dopamine in the brain, providing relief from the symptoms.
Urate, or uric acid, is a powerful antioxidant and contributes to approximately 60% of the free radical scavenging activity in the blood.
Urate forms when chemicals known as purines are broken down in the body. Previous studies have suggested that it could play a protective role within brain cells.
Dr. Xiang Gao, PhD, of Pennsylvania State University, and colleagues looked at 90,214 participants in three large, ongoing studies.
Low urate associated with higher prevalence of Parkinson's
The team carried out blood tests to measure the urate level of participants. A total of 388 people who developed Parkinson's disease after the start of the studies were compared with 1,267 people who did not have the disease.
The researchers also combined their results with the results from three previous studies on the topic for a meta-analysis.
The men with the lowest levels of urate had less than 4.9 milligrams of urate per deciliter (mg/dL). Those with the highest levels had 6.3-9.0 mg/dL. Normal levels can range from 3.5-7.2 mg/dL.
The men who had the highest levels of urate were nearly 40% less likely to develop Parkinson's disease than those with the lowest levels.
Among the men with Parkinson's disease, 45 had the highest level of urate and 58 had the lowest.
Among the healthy men, 111 were in the group with the highest level of urate and 107 were in the group with the lowest level.
The researchers adjusted for other factors that could affect Parkinson's disease risk, such as age, smoking and caffeine use.
Dr. Gao says:
"These results suggest that urate could protect against Parkinson's or slow the progression of the disease in its very early stages before symptoms are seen. The findings support more research on whether raising the level of urate in people with early Parkinson's may slow the disease down."
He notes that the study does not prove that high levels of urate protect against Parkinson's disease; it only shows an association consistent with a lower risk effect.
The findings could have implications for future therapies, as urate levels can be raised easily and inexpensively, but it must also be done cautiously, as excessively high levels of urate can cause kidney stones and gout.
More studies are also needed to understand the sex differences in the relationship between urate and Parkinson's disease, as there appeared to be no relationship between the level of urate in women and whether or not they developed Parkinson's disease.
Medical News Today recently reported that becoming infected with hepatitis C virus may increase the risk of developing Parkinson's disease.