title: Changes in prevalence and incidence of Parkinson's disease in Japan during a quarter of a century.
abstract: OBJECTIVE
  To determine the prevalence and incidence of Parkinson's disease (PD) and compare them with results from our previous studies.
  
  
  METHODS
  We examined epidemiological characteristics of PD patients using a service-based study in Yonago City, and a door-to-door study in Daisen Town. The prevalence days were April 1, 2004 in Yonago, and April 1, 2003 in Daisen.
  
  
  RESULTS
  In Yonago, we identified 254 PD patients. The crude prevalence was 180.3 (95% CI, 158.1-202.4) per 100,000 population. The adjusted prevalence was 145.8 (95% CI, 145.2-146.5) in 1980, 147.0 (95% CI, 146.3-147.6) in 1992, and 166.8 (95% CI, 166.1-167.5) in 2004, when calculated using the Japanese population in 2004. The crude incidence was 18.4 (95% CI, 11.3-25.5) per 100,000 population per year. The crude incidence in 1980 was 10.2 (95% CI, 4.6-15.8), and the adjusted incidence was 9.8 (95% CI, 4.3-15.3) in 1992, and 10.3 (95% CI, 4.7-15.9) in 2004, when calculated using the population in Yonago in 1980. In Daisen, there were 21 PD patients. The crude prevalence was 306.6 (95% CI, 175.7-437.6) and the adjusted prevalence was 192.6 (95% CI, 191.9-193.8).
  
  
  CONCLUSIONS
  The prevalence of PD had increased, primarily because the population had aged. Differences in prevalence between these adjacent areas may have resulted from differences in the methods of investigation.
authors.affiliation: Department of Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, Nishi-cho, Yonago, Japan. mika.y@med.tottori-u.ac.jp
authors.forename: Mika
authors.initials: M
authors.lastname: Yamawaki
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kusumi
authors.forename: Hisanori
authors.initials: H
authors.lastname: Kowa
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakashima
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D007407:Interviews as Topic; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology*; D015995:Prevalence; D012720:Severity of Illness Index; D012737:Sex Factors; D011795:Surveys and Questionnaires