The adverse health consequences of smoking are well known, and include increased risk of heart disease, stroke, kidney damage, and cancer. Secondhand smoke has been shown to have similar adverse health consequences among developing children. Secondhand smoke exposure has been linked to increased risk of sudden infant death syndrome (SIDS), bronchitis, pneumonia, ear infections, and asthma in children. To add to the growing list of detrimental effects of secondhand smoke, new evidence suggests that it is also associated with behavioral disorders in children. Researchers, lead by Dr. Hillel Alpert from the Harvard School of Public Health, have reported online in the journal Pediatrics that secondhand tobacco smoke exposure is associated with neurobehavioral disorders in children. The investigators evaluated the association between parent reported postnatal secondhand smoke exposure and attention-deficit/hyperactivity disorder, learning disabilities, and conduct disorders in children less than 12 years old using the 2007 National Survey on Children’s Health. The 2007 National Survey on Children’s Health was a survey that was filled out by parents regarding the health of 55,358 children. The investigators used statistical methods to account for variables that could have confounded the results. The variables that were taken into consideration were state of residence, household member smoking status, child’s age, gender, race/ethnicity, household composition, primary language spoken, household poverty status, mother’s education, foreign status of mother, legal marital status of mother, total number of children in household, total number of adults in household, and low birth weight. It was found that 6% of the children were exposed to secondhand smoke in the home. This corresponds to a total of 4.8 million children throughout the United States that are exposed to secondhand smoke. Of the children exposed to secondhand smoke, 8.2% had learning disabilities, 5.9% had attention-deficit/hyperactivity disorder, and 3.6% had behavioral or conduct disorders. When exposed to secondhand smoke in the home, children had a 50% increased chance of having 2 or more neurobehavioral disorders compared to children who did not have exposure to secondhand smoke. After evaluation of the data, it was determined that 274,100 cases of these three neurobehavioral disorders could have been prevented if the children had not been exposed to secondhand smoke in the home. The authors concluded that, “The findings of the study, which are associational and not necessarily causal, underscore the health burden of childhood neurobehavioral disorders that may be attributable to [secondhand smoke] exposure in homes in the United States”. It is important to note, as the investigators have written, that exposure to secondhand smoke is associated with these behaviors disorders and that this study does not provide evidence that secondhand smoke causes these behavioral problems. Factors that were not accounted for in the study were maternal smoking during pregnancy as well as other prenatal exposures, which could have influenced the development of these disorders. By limiting children’s exposure to secondhand smoke, it is possible that we could limit the impact that this environmental factor may play in the etiology of these disorders.
Zubair Kabir et al. “Secondhand Smoke Exposure and Neurobehavioral Disorders Among Children in the United States” Pediatrics; originally published online July 11, 2011; DOI: 10.1542/peds.2011-0023