Objectives: 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.
Materials and 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.
Keywords: epidemiology; incidence; multiple sclerosis; prevalence.
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.