title: Change in myasthenia gravis epidemiology in Trento, Italy, after twenty years.
abstract: BACKGROUND
  The recent literature suggests that the incidence and prevalence of myasthenia gravis (MG) are changing. We performed a population-based study of MG in the province of Trentino (524,826 inhabitants) and compared the results with those collected 20 years ago.
  
  
  METHODS
  Multiple sources of information (discharge diagnosis, antibody tests and anticholinesterase drugs) were analyzed. Incidence was calculated from 2005 to 2009. Prevalence was calculated on December 31, 2009. Comparison was made with descriptive statistics for 1981-1990 for the identical region.
  
  
  RESULTS
  Incidence and prevalence greatly increased in comparison with 1981-1990 data. The prevalence rate increased from 82.9 (95% confidence interval, CI, 58.4-114.3) in 1990 to 129.6 (95% CI 100.6-164.3) per million population, whereas the average annual incidence increased from 7.4 (95% CI 5-10.4) per million person-years in 1981-1990 to 14.8 (95% CI 10.5-20.3) in 2005-2009. This increase was mainly due to male patients with late-onset MG.
  
  
  CONCLUSIONS
  The study confirms the increase in incidence and prevalence of late-onset MG in the same region 20 years apart. So we should consider MG also as a disease of the elderly.
authors.affiliation: Department of Neurological Disorders, Santa Chiara Hospital, Trento, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Pallaver
authors.forename: Anna Pia
authors.initials: AP
authors.lastname: Riviera
authors.forename: Silvano
authors.initials: S
authors.lastname: Piffer
authors.forename: Roberta
authors.initials: R
authors.lastname: Ricciardi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Roni
authors.forename: Daniele
authors.initials: D
authors.lastname: Orrico
authors.forename: Domenico Marco
authors.initials: DM
authors.lastname: Bonifati
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000453:epidemiology*; D015995:Prevalence; D017678:Sex Distribution; D016019:Survival Analysis; D015996:Survival Rate