title: Is the growth of the child of a smoking mother influenced by the father's prenatal exposure to tobacco? A hypothesis generating longitudinal study.
abstract: OBJECTIVE
  Transgenerational effects of different environmental exposures are of major interest, with rodent experiments focusing on epigenetic mechanisms. Previously, we have shown that if the study mother is a non-smoker, there is increased mean birth weight, length and body mass index (BMI) in her sons if she herself had been exposed prenatally to her mother's smoking. The aim of this study was to determine whether the prenatal smoke exposure of either parent influenced the growth of the fetus of a smoking woman, and whether any effects were dependent on the fetal sex.
  
  
  METHODS
  Population-based prebirth cohort study.
  
  
  METHODS
  Avon Longitudinal Study of Parents and Children.
  
  
  METHODS
  Participants were residents of a geographic area with expected date of delivery between April 1991 and December 1992. Among pregnancies of mothers who smoked during pregnancy, data were available concerning maternal and paternal prenatal exposures to their own mother smoking for 3502 and 2354, respectively.
  
  
  METHODS
  Birth weight, length, BMI and head circumference.
  
  
  RESULTS
  After controlling for confounders, there were no associations with birth weight, length or BMI. There was a strong adjusted association of birth head circumference among boys whose fathers had been exposed prenatally (mean difference -0.35 cm; 95% CI -0.57 to -0.14; p=0.001). There was no such association with girls (interaction p=0.006). Similar associations were found when primiparae and multiparae were analysed separately. In order to determine whether this was reflected in child development, we examined the relationships with IQ; we found that the boys born to exposed fathers had lower IQ scores on average, and that this was particularly due to the verbal component (mean difference in verbal IQ -3.65 points; 95% CI -6.60 to -0.70).
  
  
  CONCLUSIONS
  Head size differences concerning paternal fetal exposure to smoking were unexpected and, as such, should be regarded as hypothesis generating.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK Centre for Child and Adolescent Health, University of Bristol, Bristol, UK Institute of Child Health, University College London, London, UK.
authors.forename: Marcus
authors.initials: M
authors.lastname: Pembrey
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: Northstone
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK Centre for Child and Adolescent Health, University of Bristol, Bristol, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Gregory
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Miller
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK Centre for Child and Adolescent Health, University of Bristol, Bristol, UK.
authors.forename: Jean
authors.initials: J
authors.lastname: Golding
mesh_terms: D000328:Adult; D002657:Child Development; D015331:Cohort Studies; D005220:Fathers; D005260:Female; D006128:Growth; D006801:Humans; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008425:Maternal Behavior; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012907:Smoking / Q000009:adverse effects*