title: Tobacco smoking and oral clefts: a meta-analysis.
abstract: OBJECTIVE
  To examine the association between maternal smoking and non-syndromic orofacial clefts in infants.
  
  
  METHODS
  A meta-analysis of the association between maternal smoking during pregnancy was carried out using data from 24 case-control and cohort studies.
  
  
  RESULTS
  Consistent, moderate and statistically significant associations were found between maternal smoking and cleft lip, with or without cleft palate (relative risk 1.34, 95% confidence interval 1.25-1.44) and between maternal smoking and cleft palate (relative risk 1.22, 95% confidence interval 1.10-1.35). There was evidence of a modest dose-response effect for cleft lip with or without cleft palate.
  
  
  CONCLUSIONS
  The evidence of an association between maternal tobacco smoking and orofacial clefts is strong enough to justify its use in anti-smoking campaigns.
authors.affiliation: Department of Medicine and Therapeutics, University of Aberdeen, Foresterhill, Scotland.
authors.forename: Julian
authors.initials: J
authors.lastname: Little
authors.forename: Amanda
authors.initials: A
authors.lastname: Cardy
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Munger
mesh_terms: D016022:Case-Control Studies; D002971:Cleft Lip / Q000453:epidemiology / Q000209:etiology*; D002972:Cleft Palate / Q000453:epidemiology / Q000209:etiology*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D014943:Global Health; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects*; D014026:Nicotiana