title: Maternal Smoking During Pregnancy and the Risk of Psychiatric Morbidity in Singleton Sibling Pairs.
abstract: BACKGROUND
  Maternal smoking during pregnancy has been associated with an increased risk for psychiatric morbidity. We further studied this with Finnish siblings to control for genetic/familial factors.
  
  
  METHODS
  From the Finnish Medical Birth Register, sibling pairs were selected as the first two children born 1987-1995 to the same mother (n = 150 168 pairs), along with information on maternal smoking (no smoking/smoking). Information on the children's psychiatric diagnoses related to outpatient care visits (1998-2013) and inpatient care (1987-2013), and the mothers' psychiatric morbidity (1969-2013) was derived from the Finnish Hospital Discharge Register. The first pair analysis compared siblings of mothers who only smoked in the first pregnancy (Quitters, 4.7%) and mothers who smoked in both pregnancies (Smokers, 9.6%); the second analysis included mothers who smoked only in the second pregnancy (Starters, 3.3%) and mothers who did not smoke in either pregnancy (Nonsmokers, 77.5%). Smoking information was missing for 5.0% of pairs. Psychiatric morbidity of the siblings and mother was included in the statistical analyses.
  
  
  RESULTS
  The risk of psychiatric diagnoses was significantly lower for the second child of quitters (adjusted OR 0.77, 95% CI 0.72-0.83) compared to the risk among smokers. A higher risk for psychiatric diagnoses was found for the second child of starters (1.39, 1.30-1.49) compared to the risk among nonsmokers. The effect of smoking was more robust for externalizing diagnoses.
  
  
  CONCLUSIONS
  Maternal smoking was independently associated with a higher risk for psychiatric morbidity in children, even when controlling thoroughly for genetic and familial factors.
  
  
  CONCLUSIONS
  Maternal smoking during pregnancy has an independent effect on the risk of psychiatric morbidity in children, even after controlling for non-measurable genetic/familial factors by using a sibling pair design. The effect of maternal smoking was robust for externalizing diagnoses. Maternal smoking during pregnancy had an effect on diagnoses both in outpatient and inpatient care.
authors.affiliation: Department of General Practice, Turku University Hospital, Turku, Finland.|Institute of Medicine, University of Turku, Turku, Finland.|Central Satakunta Federation of Municipalities, Harjavalta, Finland.
authors.forename: Mikael
authors.initials: M
authors.lastname: Ekblad
authors.affiliation: Institute of Medicine, University of Turku, Turku, Finland.|Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Turku, Finland.
authors.forename: Liisa
authors.initials: L
authors.lastname: Lehtonen
authors.affiliation: Department of Psychiatry, Institute of Medicine, University of Turku, Turku, Finland.|Harjavalta Hospital, Harjavalta, Finland.
authors.forename: Jyrki
authors.initials: J
authors.lastname: Korkeila
authors.affiliation: Information Services Department, THL National Institute for Health and Welfare, Helsinki, Finland.|Research Centre for Child Psychiatry, University of Turku, Turku, Finland.|Department of Neurobiology, Care Sciences and Society, Division of Family Medicine, Karolinska Institute, Stockholm, Sweden.
authors.forename: Mika
authors.initials: M
authors.lastname: Gissler
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D009035:Mothers / Q000706:statistics & numerical data*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012307:Risk Factors; D035781:Siblings; D012907:Smoking / Q000453:epidemiology*; D055815:Young Adult