title: Sun exposure, vitamin D intake and progression to disability among veterans with progressive multiple sclerosis.
abstract: BACKGROUND
  Early life events have been suggested to influence multiple sclerosis (MS) susceptibility, and to potentially modulate its clinical course. We assessed vitamin D-related exposures from childhood to disease onset and their associations with MS progression.
  
  
  METHODS
  Among veterans in the Multiple Sclerosis Surveillance Registry, 219 reported having the progressive form and met the inclusion criteria. Participants reported their past sun exposure, vitamin D-related intake and age at disability milestones using the Patient-Determined Disease Steps (PDDS). The Cox proportional hazards model was used to examine the association between vitamin D-related exposures and time (years) to disability.
  
  
  RESULTS
  Low average sun exposure in the fall/winter before disease onset was associated with an increased risk of progressing to a PDDS score of 8 (hazard ratio, HR: 2.13, 95% confidence interval, CI: 1.20-3.78), whereas use of cod liver oil during childhood and adolescence was associated with a reduced risk (HR: 0.44, 95% CI: 0.20-0.96).
  
  
  CONCLUSIONS
  These results suggest that exposure to vitamin D before MS onset might slow disease-related neurodegeneration and thus delay progression to disability among patients with the progressive subtype.
authors.affiliation: MS Center of Excellence-East, Baltimore VAMC, University of Maryland, Baltimore School of Medicine, Baltimore, MD, USA. tycmcdowell@hotmail.com
authors.forename: Tzu-Yun
authors.initials: TY
authors.lastname: McDowell
authors.forename: Sania
authors.initials: S
authors.lastname: Amr
authors.forename: William J
authors.initials: WJ
authors.lastname: Culpepper
authors.forename: Patricia
authors.initials: P
authors.lastname: Langenberg
authors.forename: Walter
authors.initials: W
authors.lastname: Royal
authors.forename: Christopher
authors.initials: C
authors.lastname: Bever
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Bradham
mesh_terms: D000368:Aged; D003060:Cod Liver Oil / Q000008:administration & dosage; D004185:Disability Evaluation; D006233:Persons with Disabilities; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000209:etiology*; D012306:Risk; D013472:Sunlight; D011795:Surveys and Questionnaires; D014728:Veterans; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D014807:Vitamin D; D003060:Cod Liver Oil