title: Maternal periconceptional exposure to cigarette smoking and congenital limb deficiencies.
abstract: BACKGROUND
  Congenital limb deficiencies (LD)s are characterised by the failure or disruption in formation of limbs or digits. Epidemiological research on maternal exposure to cigarette smoke and LDs is inconclusive.
  
  
  METHODS
  Data from the National Birth Defects Prevention Study were used to examine LDs and maternal exposure to active or passive cigarette smoke. Mothers of LD case (n = 906) and unaffected control (n = 8352) pregnancies from October 1997 through December 2007 reported on exposure type and quantity. Logistic regression was used to estimate adjusted odds ratio (OR) and 95% confidence interval [95% CI]; interactions with folic acid (FA) intake were tested.
  
  
  RESULTS
  For any LD, ORs were elevated for active (1.24 [95% CI 1.01, 1.53]), passive (home) (1.28 [95% CI 1.03, 1.59]), and 'active and passive' (1.34 [95% CI 1.05, 1.70]) exposures. The ORs for longitudinal LDs were elevated for passive (home) (1.62 [95% CI 1.14, 2.31]) and 'active and passive' (1.62 [95% CI 1.09, 2.41]) exposures. The OR for pre-axial LDs were elevated for any (1.39 [95% CI 1.01, 1.90]), active (1.53 [95% CI 1.03, 2.29]), passive (home) (1.82 [95% CI 1.23, 2.69]), and 'active and passive' (1.87 [95% CI 1.20, 2.92]) exposures. For lower limbs, ORs were elevated for passive (home) (1.44 [95% CI 1.01, 2.04]) and smoking 15 or more cigarettes/day (2.25 [95% CI 1.27, 3.97]). Interactions showed that ORs for any passive smoke exposure were 0.43 and 0.59 higher in the absence of FA intake for any and terminal transverse LDs.
  
  
  CONCLUSIONS
  Maternal active smoking and exposure to passive cigarette smoke emerged as a potential teratogen that affects limb and digit formation. FA was not found to mitigate the impact.
authors.affiliation: Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, IA.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Caspers
authors.forename: Paul A
authors.initials: PA
authors.lastname: Romitti
authors.forename: Shao
authors.initials: S
authors.lastname: Lin
authors.forename: Richard S
authors.initials: RS
authors.lastname: Olney
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Holmes
authors.forename: Martha M
authors.initials: MM
authors.lastname: Werler
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D017880:Limb Deformities, Congenital / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014481:United States; D055815:Young Adult
chemical_list: D014028:Tobacco Smoke Pollution
keywords: case-control studies; congenital; folic acid; limb deficiencies; maternal exposure; musculoskeletal abnormalities; pregnancy; smoking