In a recent study, children exposed to smoking in the first 4 years of life were more likely to exhibit symptoms of hyperactivity and conduct problems. The study, which is published in the Journal of Child Psychology and Psychiatry, found that the association remained even after controlling for family poverty level, parental education, parental history of attention deficit hyperactivity disorder, hostility, depression, caregiver IQ, and obstetric complications.

The effects examined in this study, which included 1,096 children, were a function of the dosage of nicotine that children were exposed to, as quantified by the metabolic byproduct cotinine in their saliva. The findings are consistent with animal models demonstrating an effect of exposure to nicotine on ongoing brain development in regions related to hyperactivity and impulsivity.

"There is a lot of emphasis on the dangers of smoking during pregnancy, but our findings indicate that children continue to be vulnerable to the adverse effects of nicotine exposure during the first several years of life," said lead author Lisa Gatzke-Kopp, PhD.

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