The occurrence of autoimmune diseases in patients with multiple sclerosis and their families

The aims of this study were to determine whether the occurrence of autoimmu ne diseases is increased in patients with multiple sclerosis (MS) and their families and whether this is influenced by the type of MS. We conducted a case-control study using a questionnaire design to determine whether the pr evalence of 11 autoimmune diseases is increased in patients with MS and the ir first-degree relatives compared to a random population control group and their first-degree relatives. We found that the total combined prevalence of the 11 autoimmune diseases was higher in the MS patients than in the con trols, with an odds ratio of 1.7 (95% confidence interval 0.9-3.2; P=0.10) increasing to 1.9 (1.0-3.5; P=0.05) after adjusting for age. For persons ag ed under 60 years, the odds ratio was 2.3 (1.1-4.6). We also found that the re was a significant increase in the total combined prevalence of the autoi mmune diseases in the first-degree relatives of MS patients compared to the first-degree relatives of the control group (P=0.003, odds ratio 2.2, conf idence interval 1.3-3.7). Patients with primary progressive MS did not diff er from patients with relapsing-remitting or secondary progressive MS in th e personal or familiar occurrence of autoimmune disease. In conclusion, alt hough there were sources of possible bias, this study suggests that individ uals with MS have a genetic predisposition to autoimmunity in general. (C) 2000 Harcourt Publishers Ltd.