Urate is a salt derived from uric acid. When the body cannot metabolize uric acid properly, urates can build up in body tissues or crystallize within the joints.
The study, published online in the Archives of Neurology, found the disease progressed more slowly in patients with the highest levels of urate than in people with the lowest levels.
Study leaders Dr. Michael Schwarzschild of Massachusetts General Hospital and Alberto Ascherio of Massachusetts General Hospital, both in Boston, said it is unknown whether the higher levels of urate actually protect Parkinson's patients or serves only as a marker of protection.
High levels of urate accumulated in the blood are known to cause gout -- a form of arthritis, especially in the big toe -- and other problems.
Schwarzchild and Ascherio based their study on data from a larger study collecting blood samples -- called DATATOP -- begun by Dr. Ira Shoulson of the University of Rochester Medical Center two decades ago. DATATOP collected blood samples, cerbrospinal fluid, and other information over an eight-year period from 800 people with Parkinson's Disease.