Risk of Parkinson's disease in a gout Mediterranean population: A case-control study.

Introduction: High levels of serum urate has been associated to a neuroprotective effect in Parkinson's disease (PD) as an antioxidant agent. However, the relation between gout and PD remains contradictory.

Objective: To study if the neuroprotective effect of serum urate is maintained in patients with gout in a large urban Mediterranean population.

Methods: Primary care based matched case-control study, carried out using an electronic health record database from the public primary care health system of Barcelona. The database contains anonymous data from 1,520,934 patients. All patients, over 40 years old, with a new diagnostic record of PD, or a new prescription of dopaminergic drugs were included (incident cases). We randomly selected four controls for each case, matched by gender and age, with the frequency matching approach. Retrospective data of PD risk factors were also collected for each individual. A multivariate logistic regression model was used to evaluate the association of gout and PD, adjusted by the presence of other risk factors.

Results: A new PD diagnosis was found in 17,629 individuals (incident diagnosis rate of 2.2 per 1000 individuals). Multivariate logistic regression model showed for gout: aOR=0.83 (0.76-0.91). When stratified by age, aOR for those under 75years was 0.99 (0.85-1.16) and 75 or over OR=0.77 (0.70-0.86). Dyslipidemia, hypertension and diabetes mellitus were associated with an increased risk of PD. Tobacco consumption was protective.

Conclusion: Our study, the first one made in a Mediterranean population, shows a PD protective effect of gout in both men and women over 75years old.