title: Prevalence of Parkinson's disease: a population-based study in Portugal.
abstract: Portugal has been identified as one of the countries with a high prevalence of LRRK2-G2019S, considered to be the most frequent known cause of familial and sporadic Parkinson's disease (PD). The aim of this study was to evaluate the prevalence of PD in Portugal using a door-to-door methodology.
  
  
  
  A cross-sectional study was conducted in the Portuguese community-dwelling population; that is, elderly people living in the community on their own, aged ≥50 years and resident in mainland Portugal, in two phases: (i) a questionnaire was applied to screen potential cases of PD; and (ii) screened cases were evaluated by an expert in PD to confirm diagnosis.
  
  
  
  The adjusted prevalence of PD for the Portuguese community-dwelling population aged ≥50 years was 0.24%. The estimated total number of cases of PD for the Portuguese population is 180/100 000 inhabitants.
  
  
  
  The results of this study show that a geographical region with a high frequency of a causal mutation for PD does not automatically imply a high prevalence of patients with PD.
authors.affiliation: Clinical Pharmacology Unit, Instituto de Medicina Molecular, Lisbon.|Neurology Department, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Lisbon.|CNS - Campus Neurológico Sénior, Torres Vedras.|Laboratory of Clinical Pharmacology and Therapeutics, Faculty of Medicine, University of Lisbon, Lisbon.
authors.forename: J J
authors.initials: JJ
authors.lastname: Ferreira
authors.affiliation: Clinical Pharmacology Unit, Instituto de Medicina Molecular, Lisbon.
authors.forename: N
authors.initials: N
authors.lastname: Gonçalves
authors.affiliation: Clinical Pharmacology Unit, Instituto de Medicina Molecular, Lisbon.
authors.forename: A
authors.initials: A
authors.lastname: Valadas
authors.affiliation: Neurology Department, Coimbra University Hospital Centre (CHUC), Coimbra.
authors.forename: C
authors.initials: C
authors.lastname: Januário
authors.affiliation: Neurology Department, S. Pedro Hospital - Trás-os-montes and Alto Douro Hospital Center, Vila Real.
authors.forename: M R
authors.initials: MR
authors.lastname: Silva
authors.affiliation: KeyPoint, Scientific Consulting Lda, Miraflores.
authors.forename: L
authors.initials: L
authors.lastname: Nogueira
authors.affiliation: Associacão Portuguesa de Doentes de Parkinson (APDPk), Lisboa.
authors.forename: J L M
authors.initials: JLM
authors.lastname: Vieira
authors.affiliation: Abel Salazar Institute for the Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal.
authors.forename: A B
authors.initials: AB
authors.lastname: Lima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology*; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence
keywords: Parkinson's disease; epidemiology; population; prevalence