title: High prevalence and increasing incidence of multiple sclerosis in the Norwegian county of Buskerud.
abstract: OBJECTIVE
  The objective was to investigate the incidence of multiple sclerosis (MS) as well as estimate the prevalence as of 1 January 2014 in the southeastern Norwegian county of Buskerud.
  
  
  METHODS
  All patients with MS living in Buskerud county in Norway between 01 January 2003 and 01 January 2014 were identified. Point prevalence of MS was identified on 01 January 2014.
  
  
  RESULTS
  We found a prevalence of 213.8 (95% CI 196.4-231.1) per 100 000. The sex ratio was 2.2:1 with a female prevalence of 293.4 (95% CI 264.7-322.2) per 100 000 and a male prevalence of 134.7 (95% CI 115.3-154.2) per 100 000. About 82% of our MS population had a confirmed relapsing-remitting MS at disease onset, while 16.8% had primary progressive MS. The mean annual incidence between 2003 and 2013 was 11.8 (95% CI 10.6-13.1) per 100 000.
  
  
  CONCLUSIONS
  This study shows a high incidence of MS in Buskerud county in southeastern Norway, and the incidence may still be on the rise. We found a relatively high prevalence of MS in our population, although this does correspond with the recently published national data. Further studies investigating both changes in incidence and possible factors causing the increasing incidence are warranted.
authors.affiliation: Department of Neurology, Drammen Hospital, Vestre Viken HF, Drammen, Norway.|Department of Neurology, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: C S
authors.initials: CS
authors.lastname: Simonsen
authors.affiliation: Department of Neurology, Drammen Hospital, Vestre Viken HF, Drammen, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Edland
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.
authors.forename: P
authors.initials: P
authors.lastname: Berg-Hansen
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.
authors.forename: E G
authors.initials: EG
authors.lastname: Celius
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000453:epidemiology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D015995:Prevalence
keywords: Norway; epidemiology; incidence; multiple sclerosis; prevalence