title: Childhood body mass index and multiple sclerosis risk: a long-term cohort study.
abstract: BACKGROUND
  Obesity in late adolescence has been associated with an increased risk of multiple sclerosis (MS); however, it is not known if body size in childhood is associated with MS risk.
  
  
  METHODS
  Using a prospective design we examined whether body mass index (BMI) at ages 7-13 years was associated with MS risk among 302,043 individuals in the Copenhagen School Health Records Register (CSHRR). Linking the CSHRR with the Danish MS registry yielded 774 MS cases (501 girls, 273 boys). We used Cox proportional hazards models to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).
  
  
  RESULTS
  Among girls, at each age 7-13 years, a one-unit increase in BMI z-score was associated with an increased risk of MS (HR(age 7)=1.20, 95% CI: 1.10-1.30; HR(age 13)=1.18, 95% CI: 1.08-1.28). Girls who were ≥95(th) percentile for BMI had a 1.61-1.95-fold increased risk of MS as compared to girls <85(th) percentile. The associations were attenuated in boys. The pooled HR for a one-unit increase in BMI z-score at age 7 years was 1.17 (95% CI: 1.09-1.26) and at age 13 years was 1.15 (95% CI: 1.07-1.24).
  
  
  CONCLUSIONS
  Having a high BMI in early life is a risk factor for MS, but the mechanisms underlying the association remain to be elucidated.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, USA. kgorham@hsph.harvard.edu
authors.forename: Kassandra L
authors.initials: KL
authors.lastname: Munger
authors.forename: Joan
authors.initials: J
authors.lastname: Bentzen
authors.forename: Bjarne
authors.initials: B
authors.lastname: Laursen
authors.forename: Egon
authors.initials: E
authors.lastname: Stenager
authors.forename: Nils
authors.initials: N
authors.lastname: Koch-Henriksen
authors.forename: Thorkild I A
authors.initials: TI
authors.lastname: Sørensen
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Baker
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000209:etiology*; D009765:Obesity / Q000150:complications*; D012307:Risk Factors
keywords: Multiple sclerosis; cohort studies; obesity; risk factors in epidemiology
references.citation: Obesity (Silver Spring). 2007 Apr;15(4):977-85
references.pmid: 17426333
references.citation: Ulster Med J. 1954 Mar;23(Suppl. 2):29-92
references.pmid: 13238438
references.citation: Proc Natl Acad Sci U S A. 2005 Apr 5;102(14):5150-5
references.pmid: 15788534
references.citation: J Immunol. 2001 May 15;166(10):5909-16
references.pmid: 11342605
references.citation: Am J Epidemiol. 2009 May 15;169(10):1167-78
references.pmid: 19357327
references.citation: Epidemiology. 2009 Jul;20(4):611-8
references.pmid: 19333127
references.citation: JAMA. 2006 Dec 20;296(23):2832-8
references.pmid: 17179460
references.citation: Public Health Nutr. 2012 Jun;15(6):1093-9
references.pmid: 22152637
references.citation: Nature. 1998 Aug 27;394(6696):897-901
references.pmid: 9732873
references.citation: Dan Med Bull. 2001 May;48(2):91-4
references.pmid: 11414126
references.citation: Ann Neurol. 1983 Mar;13(3):227-31
references.pmid: 6847134
references.citation: Neurology. 2009 Nov 10;73(19):1543-50
references.pmid: 19901245
references.citation: Int J Epidemiol. 2009 Jun;38(3):656-62
references.pmid: 18719090
references.citation: Clin Endocrinol (Oxf). 2012 Jul;77(1):26-35
references.pmid: 22168576
references.citation: Scand J Infect Dis. 2008;40(5):381-6
references.pmid: 17943636
references.citation: Ann Epidemiol. 2009 Feb;19(2):73-8
references.pmid: 18329892
references.citation: Am J Clin Nutr. 2000 Sep;72(3):690-3
references.pmid: 10966885
references.citation: Lancet Neurol. 2004 Feb;3(2):104-10
references.pmid: 14747002
references.citation: Neuroepidemiology. 2008;31(3):181-4
references.pmid: 18784417
references.citation: Eur J Clin Nutr. 2010 May;64(5):461-7
references.pmid: 20216565
references.citation: Immunity. 2007 Feb;26(2):241-55
references.pmid: 17307705
references.citation: Am J Epidemiol. 1988 Jan;127(1):104-13
references.pmid: 3337071
references.citation: Scand J Public Health. 2011 Jul;39(7 Suppl):62-4
references.pmid: 21775354
references.citation: J Neuroimmune Pharmacol. 2010 Sep;5(3):271-7
references.pmid: 20369303
references.citation: Acta Neurol Scand Suppl. 2012;(195):7-12
references.pmid: 23278650
references.citation: N Engl J Med. 2007 Dec 6;357(23):2329-37
references.pmid: 18057335
references.citation: Lancet Neurol. 2010 Jun;9(6):599-612
references.pmid: 20494325
references.citation: Mult Scler. 2012 Sep;18(9):1334-6
references.pmid: 22328681