title: Effect of Swedish snuff (snus) on preterm birth.
abstract: OBJECTIVE
  To compare the effects of Swedish snuff and cigarette smoking on risks of preterm birth.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Sweden.
  
  
  METHODS
  All live, singleton births in Sweden 1999-2006.
  
  
  METHODS
  Odds ratios (OR) with 95% confidence intervals (CI) were used to estimate relative risks for preterm birth in snuff users (n = 7607), light smokers (1-9 cigarettes/day; n = 41 436) and heavy smokers (ten or more cigarettes/day; n = 16 951) using non-tobacco users (n = 503 957) as reference.
  
  
  METHODS
  Very (<32 weeks) and moderately (32-36 weeks) preterm birth.
  
  
  RESULTS
  Compared with non-tobacco users, snuff users had increased risks of both very (adjusted OR 1.38; 95% CI 1.04-1.83) and moderately (adjusted OR 1.25; 95% CI 1.12-1.40) preterm birth. Compared with non-tobacco users, light smokers had increased risks of both very (adjusted OR 1.60; 95% CI 1.42-1.81) and moderately (adjusted OR: 1.18; 95% CI: 1.12-1.24) preterm birth, and heavy smokers had even higher risks. Among smokers, but not among snuff users, the risk was more pronounced for spontaneous than induced preterm birth.
  
  
  CONCLUSIONS
  The use of Swedish snuff was associated with increased risks of very and moderately preterm birth with both spontaneous and induced onsets. Swedish snuff is not a safe alternative to cigarette smoking during pregnancy.
authors.affiliation: Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden. anna-karin.wikstrom@kbh.uu.se
authors.forename: A-K
authors.initials: AK
authors.lastname: Wikström
authors.forename: S
authors.initials: S
authors.lastname: Cnattingius
authors.forename: M R
authors.initials: MR
authors.lastname: Galanti
authors.forename: H
authors.initials: H
authors.lastname: Kieler
authors.forename: O
authors.initials: O
authors.lastname: Stephansson
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008423:Maternal Age; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014030:Tobacco, Smokeless / Q000009:adverse effects*; D055815:Young Adult