title: Maternal smoking during pregnancy and growth in infancy: a covariance structure analysis.
abstract: BACKGROUND
  Smoking during pregnancy is related to fetal constraint and accelerated postnatal growth. However, the pathways between these factors have not been clarified. Pathway analyses that link these factors can help us better understand the mechanisms involved in this association. Therefore, this study aimed to examine pathways between maternal smoking during pregnancy and growth in infancy.
  
  
  METHODS
  Participants were singletons born between 1993 and 2006 in rural Japan. The outcome was the change in weight z-score between birth and 3 years of age. Pathways from maternal smoking and other maternal factors (such as maternal body mass index and work status) to growth in infancy via birth factors (such as birth weight and gestational age) and breastfeeding were examined using structural equation modeling.
  
  
  RESULTS
  Complete data were available for 1524 children (775 boys and 749 girls). The model fit appeared adequate. Lower birth weight and non-exclusive breastfeeding mediated the association between maternal smoking during pregnancy and rapid growth in infancy. Maternal smoking was also directly linked to rapid growth in infancy (standardized direct effects 0.06, P = 0.002). Taking all pathways into account, the standardized total effect of maternal smoking on growth in infancy was 0.11.
  
  
  CONCLUSIONS
  Maternal smoking during pregnancy may both indirectly, through birth weight and breastfeeding status, and directly influence growth during infancy; however, there may be other pathways that have not yet been identified.
authors.affiliation: Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Kohta
authors.initials: K
authors.lastname: Suzuki
authors.forename: Ryoji
authors.initials: R
authors.lastname: Shinohara
authors.forename: Miri
authors.initials: M
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokomichi
authors.forename: Zentaro
authors.initials: Z
authors.lastname: Yamagata
mesh_terms: D000328:Adult; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D015999:Multivariate Analysis; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology