The effect of maternal smoking during pregnancy on intellectual disabilities among 8-year-old children
Version of Record online: 10 JUL 2009
© 2009 Blackwell Publishing Ltd.
Paediatric and Perinatal Epidemiology
Volume 23, Issue 5, pages 482–491, September 2009
How to Cite
Braun, J. M., Daniels, J. L., Kalkbrenner, A., Zimmerman, J. and Nicholas, J. S. (2009), The effect of maternal smoking during pregnancy on intellectual disabilities among 8-year-old children. Paediatric and Perinatal Epidemiology, 23: 482–491. doi: 10.1111/j.1365-3016.2009.01056.x
- Issue online: 3 AUG 2009
- Version of Record online: 10 JUL 2009
- maternal prenatal smoking;
- gender interaction;
- low IQ
Prenatal tobacco smoke exposure has been implicated as a risk factor for cognitive deficits in children. The purpose of this study is to examine the association between prenatal tobacco smoke exposure and diagnosis of intellectual disabilities (ID) among 8-year-old children living in Arkansas, Georgia, North Carolina and Utah. In 2002 and 2004, 965 ID case children were identified through a surveillance network and compared with the population of children born in the surveillance region during the same period (n = 104 607). Prenatal tobacco smoke exposure was determined from birth certificates. We estimated the effect of prenatal tobacco smoke exposure (none, <10, 10–19 and ≥20 cigarettes per day) on ID using logistic regression.
Generally, the risk of ID was mildly elevated among children whose mothers smoked ≥20 cigarettes per day during pregnancy [RR 1.34; 95% (confidence interval) CI 0.96, 1.87] after adjustment for maternal education, maternal race, maternal age, marital status, child sex, birth year and study site. However, the effect of exposure to ≥20 cigarettes per day significantly differed for males [RR 1.77, 95% CI 1.20, 2.62] compared with females [RR 0.81, 95% CI 0.44, 1.50]. Supplemental analyses reveal substantial confounding of this relationship by socio-economic indicators. A differential effect of tobacco smoke exposure on the risk of ID is suggested for males and females and deserves further investigation; however, the interpretation is tempered by the potential for residual confounding.