Attention-Deficit Hyperactivity Disorder Symptoms and Secondhand Smoke Exposure Among Children

smoking, cigarette, secondhand smoke
There have not been very many studies which examined the association between secondhand smoke and ADHD symptoms in children. Thus, the researchers sought to evaluate whether or not there is a relationship between the two.

Exposure to secondhand smoke (SHS) increased the risk for symptoms of attention-deficit hyperactivity disorder (ADHD), according to the results of a cross-sectional study published in JAMA Network Open.

Children (N=45,562) living in 7 cities in Northeastern China were recruited between 2012 and 2013 for this study. The parents of participating children responded to the symptom inventory scale of ADHD (SIS-ADHD) and the Conners Abbreviated Symptom Questionnaire (C-ASQ). Each of the 9 symptoms of inattention and 9 of hyperactivity and impulsivity were scored on a 4-point Likert scale, and parents were asked about cigarette use inside their homes.

The children were aged mean 11.0±2.6 years and 50.3% were girls. A total of 2170 (4.8%) children had ADHD symptoms. ADHD symptoms were associated with any exposure to SHS (adjusted odds ratio [aOR], 1.50; 95% CI, 1.36-1.66; P <.001) and consistent exposure (aOR, 2.88; 95% CI, 2.55-3.25; P <.001).

Stratified by symptoms, 1816 children had inattentive ADHD (ADHD-I), 91 had hyperactivity-impulsivity ADHD (ADHD-HI), and 263 had combined (ADHD-C).

Prenatal SHS exposure was associated with ADHD-I (aOR, 2.32; 95% CI, 2.09-2.57; P <.001), ADHD-HI (aOR, 2.06; 95% CI, 1.30-3.25; P <.001), and ADHD-C (aOR, 2.08; 95% CI, 1.59-2.71; P <.001). Postnatal SHS exposure was associated with ADHD-I (aOR, 1.38; 95% CI, 1.20-1.59; P <.001), ADHD-HI (aOR, 2.11; 95% CI, 1.16-3.81; P =.01), and ADHD-C (aOR, 1.98; 95% CI, 1.39-2.81; P <.001). Current SHS exposure was only associated with ADHD-I (aOR, 1.19; 95% CI, 1.07-1.32; P <.001).

This study may have been biased by utilizing self-reported use of cigarettes and parental-assessed symptoms of ADHD.

These findings indicated SHS exposure during development and as a child were associated with symptoms of ADHD.

Reference

Lin LZ, Xu SL, Wu QZ, et al. Association of prenatal, early postnatal, or current exposure to secondhand smoke with Attention-Deficit/Hyperactivity Disorder symptoms in children. JAMA Netw Open. Published online May 20, 2021. doi:10.1001/jamanetworkopen.2021.10931