title: Increasing prevalence of multiple sclerosis in Västerbotten County of Sweden.
abstract: OBJECTIVE
  To update the incidence and prevalence of multiple sclerosis (MS) in Västerbotten County, Sweden, and to compare this to previous investigations in the same area.
  
  
  BACKGROUND
  Northern Sweden is a high-risk area for developing MS. Västerbotten County has previously been surveyed in detail regarding the occurrence of MS. In several countries, increases in MS prevalence and incidence as well as a change in the sex ratio have been reported.
  
  
  METHODS
  Multiple sources were used to identify MS cases in Västerbotten that either had their onset of the disease from 1998 to 2010 and/or lived in Västerbotten, the two dates chosen for prevalence calculation: the 31st of December 2005 and 2010.
  
  
  RESULTS
  The mean yearly incidence of MS in Västerbotten during the entire period 1998-2010 was 6.0/100,000. The female to male ratio was 2.1. The prevalence of MS in Västerbotten was 188/100,000 on 31st of December 2005 and 215/100,000 on 31st of December 2010. The MS prevalence increased over time from 1990 to 2010.
  
  
  CONCLUSIONS
  The prevalence of MS in Västerbotten County has increased between 1990 and 2010, while no statistically significant increase in incidence was seen.
authors: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.|Department of Clinical Sciences, Lund University, Lund, Sweden.
authors: A
authors: A
authors: Svenningsson
authors: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
authors: J
authors: J
authors: Salzer
authors: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
authors: M
authors: M
authors: Vågberg
authors: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
authors: P
authors: P
authors: Sundström
authors: Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden.
authors: A
authors: A
authors: Svenningsson
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology*; D015995:Prevalence; D012042:Registries; D012306:Risk; D012744:Sex Ratio; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: epidemiology; incidence; multiple sclerosis; prevalence