Prenatal and postnatal tobacco exposure and behavioral problems in 10-year-old children: results from the GINI-plus prospective birth cohort study.
BACKGROUND
Prenatal and postnatal tobacco exposure have been reported to be associated with behavioral problems. However, the magnitude of the association with tobacco exposure at specific periods of exposure is unclear.


OBJECTIVE
We assessed the relative risk of behavioral problems in children who had been exposed to tobacco smoke in utero and postnatally.


METHODS
We analyzed data from a prospective birth cohort study in two cities in Germany: the German Infant Nutrition Intervention. Our sample included 5,991 children born between 1995 and 1998 as well as their parents. We measured behavioral problems using the Strength and Difficulties Questionnaire (SDQ) at follow-up 10 years after birth. According to prespecified SDQ cutoff values, children were classified as "normal," "borderline," or "abnormal" according to the subscales "emotional symptoms," "conduct problems," "hyperactivity/inattention," "peer-relationship problems," and a total difficulties score. Smoke exposure and further covariates were assessed using parent questionnaires.


RESULTS
Compared with children not exposed to tobacco smoke, children exposed both pre- and postnatally to tobacco smoke had twice the estimated risk [95% confidence interval (CI), 1.4-3.1] of being classified as abnormal according to the total difficulties score of the SDQ at 10 years of age. Children who were only prenatally exposed had a 90% higher relative risk (95% CI, 0.9-4.0), whereas children who were only postnatally exposed had a 30% higher relative risk (95% CI, 0.9-1.9). These results could not be explained by confounding by parental education, father's employment, child's time spent in front of computer or television screen, being a single father or mother, or mother's age.


CONCLUSIONS
Prenatal exposure to tobacco smoke is associated with behavioral problems in school-age children. Although our findings do not preclude the influence of postnatal exposure, prenatal exposure seems to be more important.
Rückinger
Simon
S
Ludwig-Maximilians University Munich, Institute of Social Pediatrics and Adolescent Medicine, Division of Epidemiology, Munich, Germany. simon.rueckinger@med.uni-muenchen.de
Rzehak
Peter
P
Chen
Chih-Mei
CM
Sausenthaler
Stefanie
S
Koletzko
Sibylle
S
Bauer
Carl-Peter
CP
Hoffmann
Ute
U
Kramer
Ursula
U
Berdel
Dietrich
D
von Berg
Andrea
A
Bayer
Otmar
O
Wichmann
H-Erich
HE
von Kries
Rüdiger
R
Heinrich
Joachim
J
D002648:Child; D002653:Child Behavior Disorders / Q000209:etiology*; D002675:Child, Preschool; D015331:Cohort Studies; D004781:Environmental Exposure; D005260:Female; D005858:Germany; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution