Research | Children’s Health Prenatal and Postnatal Tobacco Exposure and Behavioral Problems in 10-Year-Old Children: Results from the GINI-plus Prospective Birth Cohort Study Rüdiger von Kries,1 and Joachim Heinrich,2 for the GINI-plus Study Group Simon Rückinger,1 Peter Rzehak,2 Chih-Mei Chen,2 Stefanie Sausenthaler,2 Sibylle Koletzko,3 Carl-Peter Bauer,4 Ute Hoffmann,4 Ursula Kramer,5 Dietrich Berdel,6 Andrea von Berg,6 Otmar Bayer,1 H.-Erich Wichmann,2 1Ludwig-Maximilians University Munich, Institute of Social Pediatrics and Adolescent Medicine, Division of Epidemiology, Munich, Germany; 2Helmholtz Zentrum München – German Research Center for Environmental Health, Institute of Epidemiology, Neuherberg, Germany; 3Ludwig-Maximilians-University of Munich, Dr. von Hauner Children’s Hospital, Munich, Germany; 4Technical University of Munich, Department of Pediatrics, Munich, Germany; 5Institut für Umweltmedizinische Forschung, IUF, University of Düsseldorf, Düsseldorf, Germany; 6Marien-Hospital Wesel, Department of Pediatrics, Wesel, Germany 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. o Bjectiv : 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-relation- ship problems,” and a total difficulties score. Smoke exposure and further covariates were assessed using parent questionnaires. r esult : 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. c onclusion : 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, pre- natal exposure seems to be more important. words k ey : adolescent health, behavioral problems, cohort study, environmental tobacco smoke exposure, strengths and difficulties questionnaire. Environ Health Perspect 118:150–154 (2010). doi:10.1289/ehp.0901209 available via http://dx.doi.org/ [Online 1 December 2009] tobacco exposure on behavioral problems. In a subset of this study, Gehring et al. (2006) tested the validity of the questionnaire-derived data on environmental tobacco smoke by measuring air nicotine and urine cotinine; the misclassification rate was below 7%, which is in line with that of other similar studies. We measured behavioral problems using the Strength and Difficulties Questionnaire (SDQ) (Goodman 1997), which allows assessment of a broad range of behavioral problems. Address correspondence to S. Rückinger, Ludwig- Maximilians-University of Munich, Institute of Social Pediatrics and Adolescent Medicine, Division of Epidemiology, Heiglhofstr. 63, 81377 München, Germany. Telephone: 49-89-7109183. Fax: 49-89- 71009315. E-mail: simon.rueckinger@med.uni- muenchen.de We thank the families for participation in the stud- ies, the obstetric units for allowing recruitment, and the GINI study teams for excellent work. The GINI-plus Study Group comprises the Institute of Epidemiology, Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Neuherberg (H.E. Wichmann, J. Heinrich, A. Schoetzau, M. Popescu, M. Mosetter, J. Schindler, K. Franke, B. Laubereau, S. Sausenthaler, A. Thaqi, A. Zirngibl, A. Zutavern, B. Filipiak, U. Gehring); Department of Pediatrics, Marien-Hospital, Wesel (D. Berdel, A. von Berg, B. Albrecht, A. Baumgart, C. Bollrath, S. Büttner, S. Diekamp, I. Groß, T. Jakob, K. Klemke, S. Kurpiun, M. Möllemann, J. Neusüss, A. Varhelyi, C. Zorn); Ludwig Maximilians University of Munich, Dr. von Hauner Children’s Hospital (S. Koletzko, D. Reinhard, H. Weigand, I. Antonie, B. Bäumler-Merl, C. Tasch, R. Göhlert, C. Sönnichsen); Clinic and Polyclinic for Child and Adolescent Medicine, University Hospital rechts der Isar of the Technical University Munich (C.P. Bauer, A. Grübl, P. Bartels, I. Brockow, U. Hoffmann, F. Lötzbeyer, R. Mayrl, K. Negele, E.-M. Schill, B. Wolf); and IUF-Environmental Health Research Institute, Düsseldorf (U. Krämer, E. Link, D. Sugiri, U. Ranft). The GINI Intervention study was funded for 3 years by grants from the Federal Ministry for Education, Science, Research and Technology (no. 01 EE 9401-4), the 6 years follow-up of the GINI- plus study was partly funded by the Federal Ministry of Environment (IUF, FKZ 20462296). This study was supported by Ludwig-Maximilians-University’s innovative research priority project MC-Health (sub- project I). The authors declare they have no competing financial interests. Received 16 July 2009; accepted 7 October 2009. ovlume 118 | number 1 | January 2010 • Environmental Health Perspectives Exposure of children to tobacco smoke, whether postnatal or in utero, is a well-known risk factor for various adverse health outcomes (DiFranza et al. 2004). An increased risk for intrauterine growth retardation, sudden infant death syndrome, and asthma are well-known adverse effects of in utero tobacco exposure (Higgins 2002). In addition, effects of in utero tobacco exposure on behavioral problems have been reported in various experimental and epi- demiologic studies (Ernst et al. 2001; Eskenazi and Castorina 1999; Wakschlag et al. 2002; Weitzman et al. 2002) including some longi- tudinal studies (Markussen Linnet et al. 2006; Wakschlag et al. 1997). Prospective studies that systematically assess a broad range of behavioral problems outcomes are sparse. Many studies have found an association between smoking in pregnancy and behav- ioral problems among children (Batstra et al. 2003; Roza et al. 2009; Saxton 1978). An 150 independent effect of postnatal tobacco expo- sure on behavioral development has also been suggested (Braun et al. 2006, 2008; Fergusson et al. 1993; Weitzman et al. 1992; Williams et al. 1998). However, specifically delineating the impact of prenatal versus postnatal tobacco exposure is a challenging task: Children whose mothers have smoked during pregnancy are likely to be exposed to tobacco smoke after birth. Furthermore, many studies use cross- sectional designs where recall bias may play an important role. The specific roles of pre- and postnatal exposure are not yet clarified. In this study, we analyzed data from the German Infant Nutritional Intervention (GINI), a large prospective birth cohort that also contains comprehensive follow-up. GINI’s prospective design and the comprehensive questions on tobacco smoke exposure at vari- ous time points provide the opportunity to dis- entangle the impacts of prenatal and postnatal