title: Seasonality of admissions with multiple sclerosis in Scotland.
abstract: OBJECTIVE
  Previous studies have described a seasonal pattern of MS relapse risk. Vitamin D and infectious triggers are two major candidate environmental risk factors proposed to account for this effect. We aimed to assess MS admissions in Scotland for a possible effect of seasonality.
  
  
  METHODS
  Acute admissions with MS were obtained from the Scottish Morbidity Register between 1997 and 2009. We compared the pattern of these to admissions with other diagnoses.
  
  
  RESULTS
  We obtained data on 7098 MS and 6 243 690 non-MS acute and day-case admissions. We found a significant difference in acute MS admissions compared with admissions with other diagnoses (P = 0.0015). There was a significant excess of Scottish MS admissions in April and June with nadirs in March and October.
  
  
  CONCLUSIONS
  Admissions with MS show a significant seasonal variation throughout the year. Further work will be needed to identify candidate environmental factors with certainty.
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
authors.forename: Adam E
authors.initials: AE
authors.lastname: Handel
authors.forename: Giulio
authors.initials: G
authors.lastname: Disanto
authors.forename: Lynne
authors.initials: L
authors.lastname: Jarvis
authors.forename: Ryan
authors.initials: R
authors.lastname: McLaughlin
authors.forename: Anastasia
authors.initials: A
authors.lastname: Fries
authors.forename: George C
authors.initials: GC
authors.lastname: Ebers
authors.forename: Sreeram V
authors.initials: SV
authors.lastname: Ramagopalan
mesh_terms: D002980:Climate; D004777:Environment; D006801:Humans; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology*; D010343:Patient Admission / Q000639:trends*; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology; D012621:Seasons; D013472:Sunlight; D013696:Temperature