title: Prevalence of myasthenia gravis in the Catalan county of Osona.
abstract: BACKGROUND
  The reported prevalence of myasthenia gravis ranges between 5 and 24 cases per 100,000, and people over 65years account for less than 50% of all cases. The prevalence and clinical characteristics of myasthenia gravis in the county of Osona were studied in patients younger and older than 65.
  
  
  METHODS
  The study draws from the county-based prospective myasthenia gravis register implemented by the Neurology Department at Hospital General de Vic in 1991.
  
  
  RESULTS
  The prevalence of myasthenia gravis was 32.89×105inhabitants (95%CI, 23.86-41.91). The standardized prevalence (European population) was 35.47×105inhabitants (95%CI, 26.10-44.84). The ratio of women to men was 1.3. Overall, the group of patients older than 65 accounted for 62.75% of all cases. The prevalence of myasthenia gravis increased considerably in older age groups. No cases were registered among patients under 25years old, prevalence was 21.87×105in the 25 to 64 age group, and prevalence in patients over 65 years increased to 122.35×105. The clinical characteristics prior to treatment and at the cut-off date are similar (P>.05) in patients younger than 65 and those aged 65 and older.
  
  
  CONCLUSIONS
  These figures show the highest prevalence rate reported to date. This high prevalence is due to the rate observed among patients older than 65. These results provide a new warning that myasthenia gravis may be underdiagnosed in the elderly population.
authors.affiliation: Servicio de Neurología, Consorci Hospitalari de Vic, Vic, Barcelona, España.
authors.forename: J M
authors.initials: JM
authors.lastname: Aragonès
authors.affiliation: Servicio de Epidemiología Clínica e Investigación, Consorci Hospitalari de Vic, Vic, Barcelona, España. Electronic address: jaltimiras@chv.cat.
authors.forename: J
authors.initials: J
authors.lastname: Altimiras
authors.affiliation: Servicio de Epidemiología Clínica e Investigación, Consorci Hospitalari de Vic, Vic, Barcelona, España.
authors.forename: P
authors.initials: P
authors.lastname: Roura
authors.affiliation: Servicio de Medicina Interna, Consorci Hospitalari de Vic, Vic, Barcelona, España.
authors.forename: F
authors.initials: F
authors.lastname: Alonso
authors.affiliation: Servicio de Neurología, Consorci Hospitalari de Vic, Vic, Barcelona, España.
authors.forename: E
authors.initials: E
authors.lastname: Bufill
authors.affiliation: Servicio de Neurología, Clínica de Vic, Vic, Barcelona, España.
authors.forename: A
authors.initials: A
authors.lastname: Munmany
authors.affiliation: Servicio de Neurología, Consorci Hospitalari de Vic, Vic, Barcelona, España.
authors.forename: S
authors.initials: S
authors.lastname: Alfonso
authors.affiliation: Unidad de Enfermedades Neuromusculares, Departamento de Neurología, Hospital de la Santa Creu i Sant Pau, Barcelona, España.
authors.forename: I
authors.initials: I
authors.lastname: Illa
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000453:epidemiology*; D015995:Prevalence; D011446:Prospective Studies; D012042:Registries; D017678:Sex Distribution; D013030:Spain / Q000453:epidemiology
keywords: Ageing; Edad avanzada; Geriatric neurology; Immunosenescence; Miastenia gravis; Myasthenia gravis; Neuroepidemiology; Neuroepidemiología; Neurogeriatría; Prevalence; Prevalencia; Senescencia inmunológica