Introduction
Registers of multiple sclerosis in Denmark
The Swedish MS registry – clinical support tool and scientific resource
Role of socio-economic and reproductive factors in the risk of multiple sclerosis
The Norwegian Multiple Sclerosis Registry and Biobank
Time trends in the incidence and prevalence of multiple sclerosis in Norway during eight decades
Socio-economic factors and immigrant population studies of multiple sclerosis
Does the changing sex ratio of multiple sclerosis give opportunities for intervention?
Multiple sclerosis and environmental factors: the role of vitamin D, parasites, and Epstein–Barr virus infection
Vitamin D and multiple sclerosis—from epidemiology to prevention
Hormonal and gender-related immune changes in multiple sclerosis
Conclusion: National incidence and risk factor assessments may become a basis for the evaluation of prevention trials – prospects from the Third Nordic MS Symposium