NEW YORK (Reuters Health) – Having gout apparently lowers the risk of developing Parkinson’s disease in older patients, according to study results published in the November 15th issue of Arthritis and Rheumatism. The finding also supports the purported protective role of uric acid.
“In vitro and in vivo studies have shown that uric acid exerts antioxidant effects on neurons,” Dr. Hyon Choi, of the University of British Columbia, Vancouver, BC, Canada, and colleagues write. “With these antioxidant properties, uric acid has been hypothesized to protect against oxidative stress, a prominent contributor to dopaminergic neuron degeneration in Parkinson’s disease (PD).”
The researchers assessed the relationship between gout and the risk of PD using data from the British Columbia Linked Health Database and PharmaCare, which provided prescription drug data for patients 65 years of age and older. The incidence rates of PD were compared between 11,258 patients with gout and 56,199 matched control subjects.
The subjects had a mean age of 74.1 years and were followed for a median of 8 years. A total of 1182 new cases of PD were identified during follow-up.
The multivariate relative risk of PD was 0.70 among patients with gout compared to those without gout. The RR was lower among patients with gout who received anti-gout treatment than those who did not receive anti-gout treatment (0.66 versus 0.79, respectively).
On the other hand, “the protective effect of gout on PD was significant among individuals who did not use diuretics (RR 0.66), but not among diuretic users (RR 0.80),” Dr. Choi’s team reports.
In subgroup analyses, the inverse association between gout and PD risk was similarly in males and females, and in patients younger or older than 75 years of age.
“These findings are consistent with the notion that hyperuricemia and gout have certain beneficial effects,” the investigators point out, “which may agree with the evolutionary advantage of relative hyperuricemia in humans.”
Arthritis Rheum 2008;59:1549-1554.