title: Maternal active smoking and risk of oral clefts: a meta-analysis.
abstract: OBJECTIVE
  To assess the association between maternal active cigarette smoking and the risk of oral clefts in the offspring.
  
  
  METHODS
  Oral clefts are divided into three subgroups: total clefts, cleft lip with or without cleft palate (CL ± P), and cleft palate only (CP). Data from studies on different levels of smoking were gathered to examine the dose-response effect.
  
  
  RESULTS
  The present meta-analysis included 29 case-control and cohort studies through Cochrane, PubMed, and Ovid Medline searches. A modest but statistically significant association was found between maternal active smoking and CL ± P (odds ratio [OR] 1.368; 95% confidence interval [CI] 1.259-1.486) as well as CP (OR 1.241; 95% CI 1.117-1.378). Half the studies showed positive dose-response effect for each subgroup (test for linear trend, P < .05).
  
  
  CONCLUSIONS
  There is a moderate risk for having a child with a CL ± P or CP in women who smoke during pregnancy. We could not confirm whether there was a positive dose-response effect between maternal smoking and clefts.
authors.affiliation: West China College of Stomatology, Sichuan University, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Xuan
authors.affiliation: West China College of Stomatology, Sichuan University, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhongpeng
authors.affiliation: West China College of Stomatology, Sichuan University, China.
authors.forename: Guo
authors.initials: G
authors.lastname: Yanjun
authors.affiliation: West China College of Stomatology, Sichuan University, China.
authors.forename: Dai
authors.initials: D
authors.lastname: Jiaqi
authors.affiliation: West China College of Stomatology, Sichuan University, China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Yuchi
authors.affiliation: Department of Cleft Lip and Palate Surgery, West China College of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Bing
authors.affiliation: Department of Cleft Lip and Palate Surgery, West China College of Stomatology, Sichuan University, Chengdu, China. Electronic address: Leechenghao_cn@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Chenghao
mesh_terms: D000328:Adult; D002971:Cleft Lip / Q000453:epidemiology*; D002972:Cleft Palate / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*