HealthDay News — Smoking and using nicotine replacement therapy during pregnancy are associated with increased risk of attention-deficit/hyperactivity disorder (ADHD) in children, according to researchers.
“It is biologically plausible that nicotine from cigarette smoke could affect the fetal brain (intrauterine effect), because increased locomotor activity and cognitive impairment have been related to in utero nicotine exposure in animal models,” explained Jin Liang Zhu, PhD, of Aarhus University in Denmark, and colleagues in Pediatrics.
“On the other hand, maternal smoking may be a marker of genetic or shared family environmental factors that cause the association. ADHD has a high level of heritability, and smoking is more prevalent in families with ADHD.”
To assess the effects of maternal smoking and nicotine replacement use during pregnancy on the risk of ADHD in the child, the investigators collected data from 84,803 female patients with single births. The association between risk of ADHD in the child and paternal smoking was used as a potential confounder.
Both maternal and paternal smoking during pregnancy was associated with increased risk of ADHD, but the association was stronger for maternal rather than paternal smoking, the researchers reported. Children born of smoking mothers and nonsmoking fathers, compared with children born of nonsmoking mothers and smoking fathers, had greater risk for ADHD (adjusted hazard ratio, 1.26; 95% CI: 1.03-1.53). Children of mothers who used nicotine replacement during pregnancy also had a greater risk of ADHD.
“Our findings suggest that exposure to prenatal tobacco smoke, possibly nicotine, may have a prenatal programming effect on the risk of ADHD in children,” wrote the inspectors.