title: Maternal smoking during pregnancy and offspring trajectories of height and adiposity: comparing maternal and paternal associations.
abstract: BACKGROUND
  Maternal smoking during pregnancy is associated with reduced offspring birth length and has been postulated as a risk factor for obesity. Causality for obesity is not established. Causality is well-supported for birth length, but evidence on persistence of height deficits is inconsistent.
  
  
  METHODS
  We examined the association between maternal smoking during pregnancy and trajectories of offspring height (0-10 years, N = 9424), ponderal index (PI) (0-2 years, N = 9321) and body mass index (BMI) (2-10 years, N = 8887) in the Avon Longitudinal Study of Parents and Children. To strengthen inference, measured confounders were controlled for, maternal and partner smoking associations were compared, dose-response and associations with post-natal smoking were examined.
  
  
  RESULTS
  Maternal smoking during pregnancy was associated with shorter birth length, faster height growth in infancy and slower growth in later childhood. By 10 years, daughters of women who smoke during pregnancy are on average 1.11 cm (SE = 0.27) shorter after adjustment for confounders and partner smoking; the difference is 0.22 cm (SE = 0.22) for partner's smoking. Maternal smoking was associated with lower PI at birth, faster PI increase in infancy, but not with BMI changes 2-10 years. Associations were stronger for maternal than partner smoking for PI at birth and PI changes in infancy, but not for BMI changes after 2 years. A similar dose-response in both maternal and partner smoking was seen for BMI change 2-10 years.
  
  
  CONCLUSIONS
  Maternal smoking during pregnancy has an intrauterine effect on birth length, and possibly on adiposity at birth and changes in height and adiposity in infancy. We do not find evidence of a specific intrauterine effect on height or adiposity changes after the age of 2 years.
authors.affiliation: MRC Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK. Laura.Howe@bristol.ac.uk
authors.forename: Laura D
authors.initials: LD
authors.lastname: Howe
authors.forename: Alicia
authors.initials: A
authors.lastname: Matijasevich
authors.forename: Kate
authors.initials: K
authors.lastname: Tilling
authors.forename: Marie-Jo
authors.initials: MJ
authors.lastname: Brion
authors.forename: Sam D
authors.initials: SD
authors.lastname: Leary
authors.forename: George Davey
authors.initials: GD
authors.lastname: Smith
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
mesh_terms: D050154:Adiposity; D000367:Age Factors; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005220:Fathers; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009035:Mothers; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000503:physiopathology*; D011446:Prospective Studies; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology* / Q000503:physiopathology