title: Maternal smoking and the risk of early weaning: a meta-analysis.
abstract: OBJECTIVE
  This study reviewed evidence on the effect of maternal smoking on early weaning.
  
  
  METHODS
  The following databases and journals were searched: Medline, Scientific Citation Index, Pediatrics, Journal of Pediatrics, New England Journal of Medicine, and Lancet. Analysis was restricted to studies in which infants who had never been breastfed were excluded or the prevalence of breastfeeding initiation was more than 90%.
  
  
  RESULTS
  In smoking vs nonsmoking mothers, the random effects odds ratio for weaning before 3 months was 1.93 (95% confidence interval [CI] = 1.55, 2.40). An adjusted odds ratio of 1.50 (95% CI = 1.34, 1.68) was shown in studies that had lost-to-follow-up rates below 15% and included adequate adjustment for confounding.
  
  
  CONCLUSIONS
  Maternal smoking increases the risk of early weaning.
authors.affiliation: Department of Social Medicine, School of Medicine and Psychology, Universidade Católica de Pelotas, Pelotas, Brazil. blhorta@uol.com
authors.forename: B L
authors.initials: BL
authors.lastname: Horta
authors.forename: M S
authors.initials: MS
authors.lastname: Kramer
authors.forename: R W
authors.initials: RW
authors.lastname: Platt
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001294:Attitude to Health; D015982:Bias; D001942:Breast Feeding / Q000523:psychology* / Q000706:statistics & numerical data*; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009035:Mothers / Q000523:psychology*; D016017:Odds Ratio; D011644:Puerperal Disorders / Q000523:psychology*; D012044:Regression Analysis; D012107:Research Design; D012307:Risk Factors; D012907:Smoking / Q000523:psychology*; D013997:Time Factors; D014886:Weaning