title: Combined effects of maternal smoking status and dietary intake related to weight gain and birth size parameters.
abstract: OBJECTIVE
  To investigate the interaction of smoking status and dietary intake during pregnancy and its relationship to maternal weight gain and birth size parameters.
  
  
  METHODS
  An observational prospective study.
  
  
  METHODS
  Free-living conditions.
  
  
  METHODS
  Four hundred and eight healthy pregnant Icelandic women.
  
  
  METHODS
  Maternal smoking status, lifestyle factors and dietary habits were evaluated with questionnaires. Intake of foods and supplements was also estimated with a semiquantitative food frequency questionnaire for the previous 3 months. All questionnaires were filled out between 11 and 15 weeks and between 34 and 37 weeks of gestation. Smoking status in relation to optimal and/or excessive weight gain during pregnancy was represented with logistic regression controlling for potential confounding factors.
  
  
  METHODS
  Maternal weight gain, smoking status, dietary intake and birthweight.
  
  
  RESULTS
  Women who smoked throughout pregnancy were unlikely to gain optimal weight or more (OR 0.51, 95% CI 0.27-0.97), whereas smoking cessation in connection with pregnancy ('former smokers') doubled the risk of excessive weight gain (OR 2.03, 95% CI 1.24-3.35). The latter association was no longer significant after adjustment for dietary factors and other confounding factors. Former smokers ate the least amount of fruit and vegetables (fruit: 129 versus 180 and 144 g/day (median), P= 0.038; vegetables: 53 versus 76 and 72 g/day, P= 0.026 for former smokers, nonsmokers and smokers, respectively). Birthweight was lowest among infants born to smokers, but birthweight was similar for former smokers and nonsmokers (3583 +/- 491 g versus 3791 +/- 461 g and 3826 +/- 466 g, respectively; P= 0.003).
  
  
  CONCLUSIONS
  Smoking cessation in early pregnancy or pre-pregnancy is not associated with low birthweight. It is, however, associated with excessive maternal weight gain and a low fruit and vegetable intake.
authors.affiliation: Unit for Nutrition Research, Landspitali-University Hospital, Reykjavik, Iceland.
authors.forename: A S
authors.initials: AS
authors.lastname: Olafsdottir
authors.forename: G V
authors.initials: GV
authors.lastname: Skuladottir
authors.forename: I
authors.initials: I
authors.lastname: Thorsdottir
authors.forename: A
authors.initials: A
authors.lastname: Hauksson
authors.forename: L
authors.initials: L
authors.lastname: Steingrimsdottir
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D006801:Humans; D008019:Life Style; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D012907:Smoking / Q000009:adverse effects*; D015430:Weight Gain / Q000502:physiology*