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).


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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