Epidemiology of Multiple Sclerosis.

The epidemiology of multiple sclerosis (MS) includes a consideration of genetic and environmental factors. Comparative studies of different populations have revealed prevalence and incidence rates that vary with geography and ethnicity. With a prevalence ranging from 2 per 100,000 in Japan to greater than 100 per 100,000 in Northern Europe and North America, the burden of MS is similarly unevenly influenced by longevity and comorbid disorders. Well-powered genome-wide association studies have investigated the genetic substrate of MS, providing insight into autoimmune mechanisms involved in the etiopathogenesis of MS and elucidating possible avenues of biological treatment.