Multiple sclerosis in Vest-Agder County, Norway.

OBJECTIVE To examine multiple sclerosis (MS) prevalence, rate of immunomodulatory treatment and frequency of Borrelia burgordorferi (Bb) antibodies in Vest-Agder, Norway. MATERIALS AND METHODS Patients in the period 1996-2006 who met the Poser criteria for definitive or probable MS were included. Clinical and demographical data, and presence of Bb antibodies were registered. RESULTS A total of 295 patients were identified. The crude prevalence was 180 per 100,000 population (95% CI=160.9-218.0), age-adjusted prevalence was 186 per 100,000 population (95% CI=166.3-225.3). The age-adjusted incidence rates were 7.5 and 8.0 for 1996-2000 and 2001-2006, respectively. Thirty-eight per cent were treated with immunomodulatory agents when compared to 28% in the rest of the country. Bb serum antibodies were detected in 7% of patients with MS. CONCLUSIONS Vest-Agder county has the highest prevalence of MS reported in Norway, and a high treatment rate. Bb antibodies were not more prevalent than in healthy individuals.