title: Timing of use of cod liver oil, a vitamin D source, and multiple sclerosis risk: The EnvIMS study.
abstract: BACKGROUND
  Low vitamin D levels have been associated with an increased risk of multiple sclerosis (MS), although it remains unknown whether this relationship varies by age.
  
  
  OBJECTIVE
  The objective of this paper is to investigate the association between vitamin D3 supplementation through cod liver oil at different postnatal ages and MS risk.
  
  
  METHODS
  In the Norwegian component of the multinational case-control study Environmental Factors In Multiple Sclerosis (EnvIMS), a total of 953 MS patients with maximum disease duration of 10 years and 1717 controls reported their cod liver oil use from childhood to adulthood.
  
  
  RESULTS
  Self-reported supplement use at ages 13-18 was associated with a reduced risk of MS (OR 0.67, 95% CI 0.52-0.86), whereas supplementation during childhood was not found to alter MS risk (OR 1.01, 95% CI 0.81-1.26), each compared to non-use during the respective period. An inverse association was found between MS risk and the dose of cod liver oil during adolescence, suggesting a dose-response relationship (p trend = 0.001) with the strongest effect for an estimated vitamin D3 intake of 600-800 IU/d (OR 0.46, 95% CI 0.31-0.70).
  
  
  CONCLUSIONS
  These findings not only support the hypothesis relating to low vitamin D as a risk factor for MS, but further point to adolescence as an important susceptibility period for adult-onset MS.
authors.affiliation: The KG Jebsen Centre for MS-Research, Department of Clinical Medicine, University of Bergen, Norway/Department of Global Public Health and Primary Care, University of Bergen, Norway/Department of Nutrition, Harvard T.H. Chan School of Public Health, USA Marianna.Cortese@igs.uib.no.
authors.forename: Marianna
authors.initials: M
authors.lastname: Cortese
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Norway/The Norwegian Multiple Sclerosis Competence Center, Department of Neurology, Haukeland University Hospital, Norway.
authors.forename: Trond
authors.initials: T
authors.lastname: Riise
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Norway/Department of Nutrition, Harvard T.H. Chan School of Public Health, USA/The Norwegian Multiple Sclerosis Competence Center, Department of Neurology, Haukeland University Hospital, Norway.
authors.forename: Kjetil
authors.initials: K
authors.lastname: Bjørnevik
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Norway/Department of Neurology, Akershus University Hospital, Norway.
authors.forename: Trygve
authors.initials: T
authors.lastname: Holmøy
authors.affiliation: Department of Neurology, University Hospital of North Norway, Norway.
authors.forename: Margitta T
authors.initials: MT
authors.lastname: Kampman
authors.affiliation: Department of Epidemiology and Biostatistics and Occupational Health, McGill University, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Magalhaes
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Norway/Department of Clinical and Experimental Medicine, University of Sassari, Italy/Division of Medicine, McGill University, Canada.
authors.forename: Maura
authors.initials: M
authors.lastname: Pugliatti
authors.affiliation: Department of Epidemiology and Biostatistics and Occupational Health, McGill University, Canada/Research Institute of the McGill University Health Centre, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Wolfson
authors.affiliation: The KG Jebsen Centre for MS-Research, Department of Clinical Medicine, University of Bergen, Norway/The Norwegian Multiple Sclerosis Competence Center, Department of Neurology, Haukeland University Hospital, Norway.
authors.forename: Kjell-Morten
authors.initials: KM
authors.lastname: Myhr
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D002762:Cholecalciferol / Q000627:therapeutic use*; D003060:Cod Liver Oil / Q000627:therapeutic use*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology / Q000517:prevention & control*; D009664:Norway / Q000453:epidemiology; D012042:Registries; D012306:Risk; D055815:Young Adult
chemical_list: D002762:Cholecalciferol; D003060:Cod Liver Oil
keywords: Multiple sclerosis; age; cod liver oil; environmental risk factors; supplementation; susceptibility; timing; vitamin D