title: Change in sex ratio, disease course and age at diagnosis in Oslo MS patients through seven decades.
abstract: OBJECTIVE
  To study changes in sex ratio, disease course, time from onset to diagnosis and age at diagnosis by year of birth in a well-defined population of multiple sclerosis (MS) patients.
  
  
  METHODS
  Based on the Oslo MS Registry patients born from 1910 to 1980 with residence in Oslo at time of diagnosis were studied. Data were analyzed by 10-year intervals based on year of birth.
  
  
  RESULTS
  The female to male ratio increased significantly from 1.48 to 2.30 through seven decades. Also, the ratio of initial relapsing-remitting (RR-MS) to primary progressive (PP-MS) disease course increased significantly from 1.93 to 16.00. The time from onset to diagnosis and the mean age at diagnosis declined significantly during the same period.
  
  
  CONCLUSIONS
  This study shows that there has been a change in MS sex ratio, disease course and age at diagnosis through a period of seven decades, suggesting an environmental factor mainly affecting women at a younger age and causing a RR-MS disease course.
authors: Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway. elgu@uus.no
authors: E G
authors: EG
authors: Celius
authors: C
authors: C
authors: Smestad
mesh_terms: D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D018450:Disease Progression; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D012189:Retrospective Studies; D012744:Sex Ratio