According to a report by the Centers for Disease Control and Prevention (CDC), an estimated 19% of American adults smoked cigarettes in 2011. It is well established that prenatal nicotine exposure, even through maternal smokeless tobacco use, is associated with numerous postnatal adverse health outcomes in newborns including low birth weight, preterm delivery, and sudden infant death syndrome. The association of tobacco use during pregnancy with severe neuropsychiatric disorders in offspring is starting to be elucidated.
New research findings published in Journal of the American Academy of Child & Adolescent Psychiatry indicate that nicotine exposure during pregnancy through cigarette smoking is associated with increased risk for Tourette syndrome and chronic tic disorder (TS/CT), as well as TS/CT with comorbid psychiatric conditions including attention-deficit/hyperactivity disorder (ADHD).
Nicotine has many adverse effects on fetal brain development, and maternal tobacco smoking during pregnancy has previously been linked with numerous long-term neurodevelopmental abnormalities and child behavioral problems such as ADHD, depression, anxiety, conduct disorder, and antisocial behavior.
In the present study, a team of investigators affiliated with Icahn School of Medicine at Mount Sinai, New York and Aarhus University, Denmark, identified more than 90 000 pregnancies from The Danish National Birth Cohort (DNBC) study with detailed information on lifestyle and health behaviors in order to examine the role of prenatal maternal smoking in risk for TS/CT and pediatric-onset obsessive-compulsive disorder (OCD), as well as in risk for TS/CT with comorbid ADHD or other comorbid, severe psychiatric diagnoses.
They then calculated incidence rates per 1 000 persons for each of these diagnostic categories, and they calculated hazard ratios (HR) by adjusting for sex of the offspring, parity, birth year, maternal age, psychiatric history and body-mass index (BMI), as well as socioeconomic status, alcohol consumption, and caffeine intake. Out of of 89 189 children, approximately 1% were diagnosed with either TS/CT spectrum (n=531) or OCD (n=294).
In this largest-to-date birth cohort study, investigators reported an approximately 65% higher risk for TS/CT (adjusted HR=1.69, 95% CI=1.19-2.39) in offspring with regard to heavy maternal smoking (more than 10 cigarettes per day) during pregnancy. Along the same lines, they also reported a 2-fold increased risk for TS/CT with comorbid ADHD (adjusted HR=1.94, 95% CI=1.14-3.29). “We observed similar trends with pediatric-onset OCD compared to TS/CT; however, the smaller number of OCD cases resulted in lower power to determine significant findings,” researchers noted in their publication.
Taken together, smoking cessation strategies in pregnancy should be widely implemented, as the prevalence of tobacco use among pregnant women is relatively high (20% to 25%). It has previously been reported that behavioral counseling interventions hold the greatest promise for abstinence from cigarette smoking in both the general population and among pregnant women.
Browne HA, Modabbernia A, Buxbaum JD, et al. Prenatal maternal smoking and increased risk for Tourette syndrome and chronic tic disorders. J Am Acad Child Adolesc Psychiatry. 2016; 55(9):784-791.