title: Association between maternal smoking during pregnancy and recurrent wheezing in infancy: evidence from a meta-analysis.
abstract: BACKGROUND
  Quantification of the association between the maternal smoking during pregnancy and recurrent wheezing in infancy is still conflicting. Thus, we performed a comprehensive meta-analysis to test the hypothesis that maternal smoking during pregnancy may increase the risk of recurrent wheezing in infancy.
  
  
  METHODS
  Pertinent studies were identified by a search in PubMed and Web of Knowledge up to October 2014. Random-effect model (REM) or fixed effects model (FEM) was used to combine study-specific results. Publication bias was estimated using Egger's regression asymmetry test.
  
  
  RESULTS
  Seven articles (3 cohort study and 4 cross-sectional studies) involving 8579 recurrent wheezing infant cases about maternal smoking during pregnancy and recurrent wheezing risk were used in this meta-analysis. The combined relative risks (RRs) of recurrent wheezing infants associated with maternal smoking during pregnancy was 1.491 (95% CIs = 1.329-1.672) overall. Significant associations were found both in Europe [RRs = 1.471, 95% CIs = 1.287-1.681] and other populations [RRs = 1.720, 95% CIs = 1.119-2.644] and cross-sectional studies [RRs = 1.474, 95% CIs = 1.306-1.663]. No publication bias was found.
  
  
  CONCLUSIONS
  Our analysis indicated that maternal smoking during pregnancy could increase the risk of recurrent wheezing in infancy.
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Chunhong
authors.initials: C
authors.lastname: Duan
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Meiyun
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Ding
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Huafeng
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Pediatrics, Jinan Children's Hospital Jinan, Shandong, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Han
keywords: Maternal smoking; infancy; meta-analysis; recurrent wheezing