Familial occurrence of Parkinson's disease in a community-based case-control study

Purpose: To study the occurrence of Parkinson's disease (PD) in the relatives of parkinsonian patients (n=119), and of their matched controls (n=238).Scope: More patients reported a positive family history of PD in their first degree relatives, compared to their controls (OR 2.7, 95% CI 1.3-5.9), and the incidence of PD among those relatives was also significantly higher (OR 1.4, 95% CI 1.1-1.8).Conclusions: Familial occurrence of PD is not necessarily a sign of genetic mechanisms in the etiology of PD. Shared environment with common risk factors might be even more important.