Descriptive epidemiology of parkinsonism in the Canton of Geneva, Switzerland

Abstract Objectives A large descriptive cross-sectional population-based prevalence study as well as a retrospective incidence study were undertaken to ascertain the frequency of Parkinson's Disease (PD) and other types of degenerative and non-degenerative parkinsonism in the Canton of Geneva, Switzerland. Methods An extensive case-finding approach including records from public hospitals, private neurologists and nursing homes was utilized. All patients with a diagnosis of parkinsonism established between 2003 and 2012 were included. Diagnosis of parkinsonism was ascertained by a movement disorders specialist, based on published and validated consensus diagnostic criteria. Results A total of 1235 living patients with parkinsonism were identified, from which 80% presented with a degenerative form and 20% with a non-degenerative form of parkinsonism. Among the former, PD was the most frequent diagnosis (81%, age-adjusted prevalence: 183/10 5 inhabitants, age-adjusted average annual incidence: 20/10 5 /year) followed by dementia with Lewy bodies (9%), progressive supranuclear palsy (3.9%), multisystem atrophy (1.9%) and corticobasal syndrome (1.4%). Among non-degenerative parkinsonism, drug-induced parkinsonism was the most frequent diagnosis (43.4%), followed by vascular parkinsonism (37%), normal pressure hydrocephalus (5.1%) and parkinsonism in the context of a psychiatric disorder or functional parkinsonism (3.8%). Crude, age-, sex-specific and age-adjusted prevalence and incidence of all types of parkinsonism are detailed for each diagnosis. Conclusion This is the first Swiss population-based epidemiological study of PD and parkinsonism. It provides an extensive overview of the prevalence and incidence of degenerative and non-degenerative forms of parkinsonism. These data may assist clinicians with their clinical workup.