The authors determined the relationship between tobacco smoking and the risk of developing multiple sclerosis (MS) in a general population of 22,312 individuals living in Hordaland, Norway in 1997. A total of 87 individuals reported having developed MS. The risk of MS was higher among smokers than among never-smokers (rate ratio 1.81, 95% CI 1.1 to 2.9; p = 0.014). Studies on how smoking interacts with disease onset may contribute to determining the causal agents of this disease.
Department of Public Health and Primary Health Care, Section of Occupational Medicine, University of Bergen, Norway. firstname.lastname@example.org