A new study has found that exposure to tobacco smoke during early childhood is tied to a greater risk for the development of emotional and behavioral disorders during the school years. The link is strongest for children who were exposed while still in utero and during very early infancy.
Researchers have long known about the serious physical health problems suffered by many children who experience early exposure to environmental tobacco smoke (ETS). These ailments may include bronchitis, pneumonia, asthma, ear infections, and even sudden infant death syndrome (SIDS). In fact, smoking during pregnancy results in 1,000 U.S. infant deaths per year, according to the Centers for Disease Control and Prevention (CDC).
The potential role of ETS in childhood emotional and behavioral problems, however, has been much less understood. In an effort to study this potential link further, researchers from Pierre and Marie Curie University (UPMC) and Inserm, a French institute for research, analyzed data on pre- and postnatal exposure to tobacco in the homes of 5,221 primary school children.
“Exposure to ETS in the postnatal period, alone or in association with exposure during pregnancy, increases the risk of behavioral disorders in primary school children,” said Inserm Research Director Dr. Isabella Annesi-Maesano.
Prenatal (in utero smoking) and postnatal exposure to tobacco smoke in the home were assessed using a standardized questionnaire completed by the parents. Behavioral disorders were assessed with the Strengths and Difficulties Questionnaire (SDQ) which is commonly given to assess the behavioral and psychosocial functioning of children. This form was also completed by the parents.
The findings showed that emotional disorders are associated with exposure to ETS during both the prenatal and postnatal periods. This affected 21 percent of the children in the study. Conduct disorders were also found to be linked to ETS exposure in these children. The association also exists in cases of prenatal or postnatal exposure alone, but is less pronounced.
These observations seem to confirm previous findings from animal studies, which showed that the nicotine contained in tobacco smoke may have a neurotoxic effect on the brain. During pregnancy, nicotine in tobacco smoke stimulates acetylcholine receptors, and causes structural changes in the brain. In the first months of life, exposure to tobacco smoke generates a protein imbalance that leads to altered neuronal growth.
“Our data indicate that passive smoking, in addition to the well-known effects on health, should also be avoided because of the behavioral disorders it may cause in children,” concluded the researchers.
The findings are published in the journal PLOS ONE.