Sveinbjornsdottir S, Magnusson H, Benedikz JE Multiple sclerosis in Iceland from 1900 to 2000: A total population study. Mult Scler Relat Disord. 2014;3(3):375-83.
The epidemiology of multiple sclerosis (MS) in Iceland in1900-2000 is presented. The incidence increased significantly from 2.58×100,000 in 1950 to 5.06×100,000 in 2000 (from 2.71 to 7.03×100,000 for women and from 2.55 to 3.10×100,000 for men) with a yearly increase by a factor of 1.0816 per year for women and 1.01207 per year for men . Prevalence standardized to the European standard population rose from 29.9×100,000 in 1950 to 131.7×100,000 in 2000. The standardized prevalence was constantly higher amongst women (42.8-181.6×100,000 vs. 16.7-81.5×100,000 for men) with a female to male ratio of 2.6 in 1950 and in 2000. Mean age at onset for all patients increased from 27.8 years in 1950 to 30.7 years in 2000 (from 27.0 to 30.1 years for women and from 28.6 to 32.2 years for men). Children and adolescents (<18 years) were 9.6% of all, of whom 60% were diagnosed after 1970. Mean age of onset for children and adolescents was 14.7 years (9-17 years, 95% CI 4.2 years). The rise in incidence and prevalence can have multiple explanations, including diagnosis of milder forms of MS, increased awareness of MS in the older population, better diagnostic measures and longer survival but the authors find it likely that there has been a true rise in the MS incidence.