title: Body size and the risk of multiple sclerosis in Norway and Italy: the EnvIMS study.
abstract: BACKGROUND
  Obesity may be a risk factor for developing multiple sclerosis (MS).
  
  
  OBJECTIVE
  We examined if body size influences the risk of MS in a population-based, case control study.
  
  
  METHODS
  A total of 953 cases and 1717 controls from Norway and 707 cases and 1333 controls from Italy reported their body size by choosing a silhouette 1 to 9 (largest) every fifth year from age 5 to 30 and at time of study. The body size-related MS risk was defined by odds ratios (ORs) in logistic regression analyses adjusting for age, smoking and outdoor activity.
  
  
  RESULTS
  In Norway a large body size (silhouettes 6-9) compared to silhouette 3 increased the risk of MS, especially at age 25 (OR 2.21; 95% CI 1.09-4.46 for men and OR 1.43; 95% CI 0.90-2.27 for women). When comparing silhouette 9 to 1, we found a significant dose-response from age 10 until age 30 peaking at age 25 (sex-adjusted OR 2.83; 95% CI 1.68-4.78). The association was present for at least 15 years prior to disease onset. No significant associations were found in Italy.
  
  
  CONCLUSIONS
  Obesity from childhood until young adulthood is a likely risk factor for MS with a seemingly stronger effect in Norway than in Italy.
authors.affiliation: University of Bergen/The Norwegian MS Competence Centre, Haukeland University Hospital, Norway kristin.wesnes@gmail.com.
authors.forename: Kristin
authors.initials: K
authors.lastname: Wesnes
authors.affiliation: University of Bergen/The Norwegian MS Competence Centre, Haukeland University Hospital, Norway.
authors.forename: Trond
authors.initials: T
authors.lastname: Riise
authors.affiliation: Section of Clinical Neurology, University of Ferrara, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Casetta
authors.affiliation: Clinic of Neurology, Faculty of Medicine, University of Belgrade, Serbia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Drulovic
authors.affiliation: Section of Clinical Neurology, University of Ferrara, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Granieri
authors.affiliation: Institute of Clinical Medicine, Faculty of Medicine, University of Oslo/Akershus University Hospital, Norway.
authors.forename: Trygve
authors.initials: T
authors.lastname: Holmøy
authors.affiliation: University of Tromsø/University Hospital of North Norway, Norway.
authors.forename: Margitta T
authors.initials: MT
authors.lastname: Kampman
authors.affiliation: Division of Neurology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Landtblom
authors.affiliation: Darmstadt, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Lauer
authors.affiliation: Institute of Clinical Medicine, Faculty of Medicine, University of Oslo/Institute of Immunology, Oslo University Hospital Rikshospitalet, Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lossius
authors.affiliation: Department of Epidemiology and Biostatistics and occupational health, McGill University, Montreal, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Magalhaes
authors.affiliation: Institute of Epidemiology, Faculty of Medicine, University of Belgrade, Serbia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Pekmezovic
authors.affiliation: University of Bergen/The Norwegian MS Competence Centre, Haukeland University Hospital, Norway.
authors.forename: Kjetil
authors.initials: K
authors.lastname: Bjørnevik
authors.affiliation: Research institute of the McGill University Health Centre, Montreal, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Wolfson
authors.affiliation: University of Bergen, Norway/ Department of Clinical and Experimental Medicine, University of Sassari, Italy.
authors.forename: Maura
authors.initials: M
authors.lastname: Pugliatti
authors.affiliation: The Norwegian MS Competence Centre, Haukeland University Hospital/The KG Jebsen Centre for MS-Research, University of Bergen, Norway.
authors.forename: Kjell-Morten
authors.initials: KM
authors.lastname: Myhr
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D049628:Body Size; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology*; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D012307:Risk Factors; D055815:Young Adult
keywords: Multiple sclerosis; body mass index; body size; case control studies; epidemiology; obesity; vitamin D