title: No effect of preterm birth on the risk of multiple sclerosis: a population based study.
abstract: BACKGROUND
  Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. A clear parent of origin effect has been shown in several populations, perhaps resulting from factors operating during gestation. Preterm birth (birth at less than 37 weeks gestational age) has been shown to result in long-term health problems, including impaired neurological development. Here, in a population-based cohort, we investigate whether preterm birth increases the risk to subsequently develop MS.
  
  
  METHODS
  We identified 6585 MS index cases and 2509 spousal controls with preterm birth information from the Canadian Collaborative Project on Genetic Susceptibility to MS. Rates of individuals born preterm were compared for index cases and controls.
  
  
  RESULTS
  There were no significant differences between cases and controls with respect to preterm births. 370 (5.6%) MS index cases and 130 (5.2%) spousal controls were born preterm, p = 0.41.
  
  
  CONCLUSIONS
  Preterm birth does not appear to contribute to MS aetiology. Other factors involved in foetal and early development need to be explored to elucidate the mechanism of the increased risk conferred by the apparent maternal effect.
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK. sramagopalan@gmail.com
authors.forename: Sreeram V
authors.initials: SV
authors.lastname: Ramagopalan
authors.forename: William
authors.initials: W
authors.lastname: Valdar
authors.forename: David A
authors.initials: DA
authors.lastname: Dyment
authors.forename: Gabriele C
authors.initials: GC
authors.lastname: DeLuca
authors.forename: Sarah-Michelle
authors.initials: SM
authors.lastname: Orton
authors.forename: Irene M
authors.initials: IM
authors.lastname: Yee
authors.forename: Maria
authors.initials: M
authors.lastname: Criscuoli
authors.forename: George C
authors.initials: GC
authors.lastname: Ebers
authors.forename: A Dessa
authors.initials: AD
authors.lastname: Sadovnick
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors