OBSERVATIONS ON SERUM URIC-ACID LEVELS AND THE RISK OF IDIOPATHIC PARKINSONS-DISEASE

Uric acid, an antioxidant found in high concentrations in serum and in the brain, has been hypothesized to protect against oxidative damage and cell death in Parkinson's disease, The authors tested this hypothe sis among men participating in a 30-year prospective study known as th e Honolulu Heart Program, Serum uric acid was measured in 7,968 men at the baseline examination held from 1965 to 1968, Of these men, 92 sub sequently developed idiopathic Parkinson's disease (IPD), In analyses adjusted for age and smoking, men with uric acid concentrations above the median at enrollment had a 40% reduction in IPD incidence (rate ra tio (RR) = 0.6; 95% confidence interval (CI) 0.4-1.0), Reduced IPD inc idence rates persisted in analyses restricted to nonsmokers (RR = 0.5; 95% CI 0.3-1.0) and cases younger than age 75 years (RR = 0.5; 95% CI 0.3-0.9), Incidence rates were not notably affected when analyses wer e restricted to cases that occurred more than 5 years after uric acid measurement (RR = 0.6; 95% CI 0.4-1.0). Inclusion of known or computed correlates of uric acid in regression models did not substantially ch ange risk of IPD, This study provides prospective evidence of an assoc iation between uric acid and reduced occurrence of IPD and indicates t hat further investigations of this association are warranted.