Prevalence and incidence of Parkinson's disease in The Faroe Islands.

OBJECTIVE: A study in The Faroe Islands in 1995 suggested a high prevalence of idiopathic Parkinson's disease (IPD) and total parkinsonism of 187.6 and 233.4 per 100,000 inhabitants respectively.

METHODS: Detailed case-finding methods 10 years later were used and a neurologist has verified the diagnosis.

RESULTS: The crude prevalence of IPD and total parkinsonism was 206.7 per 100,000 and 227.4 per 100,000 respectively. The age-adjusted prevalence is twice as high as data from Norway and Denmark. Age at initiation of treatment and the fatality rate did not explain the increased prevalence. During 1995-2005, the average annual incidence was 21.1 per 100,000 persons for Parkinson's disease, and 22.9 per 100,000 persons, if including atypical parkinsonism.

CONCLUSION: The high prevalence was verified and linked to a high incidence. The cause of the high prevalence is unknown, but neurotoxic contaminants in traditional food may play a role in the pathogenesis in this population, perhaps jointly with genetic predisposition.