A new study has found that high levels of urate in the blood is linked to a reduced risk of Parkinson's disease.
The study, conducted by researchers at the Harvard School of Public Health (HSPH), was led by Marc Weisskopf, Assistant Professor of Environmental and Occupational Epidemiology.
Urate is a normal component of blood, and although high levels can lead to gout, urate might also have beneficial effects because it is a potent antioxidant.
Parkinson's disease is a chronic, progressive nerve disorder associated with destruction of brain cells producing dopamine, a neurotransmitter essential to the normal functioning of the central nervous system.
Marc Weisskop said that the results of the study provided the 'strongest evidence to date' that urate, a normal component of blood might also have beneficial effects in its capacity as a potent antioxidant.
High levels of urate in the blood can lead to gout.
"This is the strongest evidence to date that urate may protect against Parkinson's disease," said Weisskopf.
As a part of the study the researchers used data form the HSPH-based Health Professionals Follow-up Study, a population of male health professionals established in 1986. The study cohort included more than 18,000 men without Parkinson's disease who had provided blood samples between 1993 and 1995 and whose subsequent health status was followed.
The researchers found that men in the top quartile of blood urate concentration had 55 percent lower risk of developing Parkinson's disease than men in the bottom quartile. This difference was not explained by differences in age or other risk factors for Parkinson's disease.
The authors hypothesize that urate's antioxidant properties may help dampen the effects of oxidative stress, which appears to contribute to the progressive loss of the dopamine-producing brain cells that occurs in individuals with Parkinson's disease.
A team of researchers led by Alberto Ascherio, Associate Professor of Nutrition and Epidemiology at HSPH and senior author of the study and Michael Schwarzschild a movement disorder specialist at Massachusetts General Hospital then followed up on this clue and accessed the databases of two large, randomized studies conducted among patients with early Parkinson's disease.
The preliminary results, presented in abstract form at recent meetings, showed a slower progression of the disease among individuals with high blood urate.
"It is still uncertain whether urate exerts a neuroprotective effect, but approaches to elevating urate levels are nonetheless worth considering as a potential neuroprotective strategy," said Ascherio.
"But elevating blood urate increases the risk of kidney stones and may have adverse cardiovascular effects and should only be attempted in the context of a closely monitored randomized trial until beneficial effects are proven," he added.
The study was supported by National Institutes of Health/National Institute of Neurological Disorders and Stroke, the Kinetics Foundation and the Intramural Research Program of the National Institutes of Health/National Institute of Environmental Health Sciences.
The findings were published online on June 20, 2007 in The American Journal of Epidemiology and will appear in an upcoming print issue of the journal.