Association of prenatal, early postnatal, or current indirect smoking exposure with symptoms of attention-deficit/hyperactivity disorder
Exposure to SHS from pregnancy through childhood was associated with a higher probability of having ADHD symptoms and subtypes among school-aged children, and the association between prenatal and early postnatal SHS exposure was somewhat stronger. Our findings highlight the important public health implications of reducing SHS exposure, which may reduce the health and economic burden of individuals with ADHD.
Lin L, Xu S, Wu Q, et al. Association of prenatal, early postnatal, or current indirect smoking exposure with symptoms of attention-deficit/hyperactivity disorder. JAMA Network Open. 2021; 4(5): e2110931. doi: 10.1001 / jamanetworkopen.2021.10931
Commentary
The purpose of this study was to evaluate the association between prenatal, postnatal, or current SHS exposure and ADHD symptoms and subtypes in school-aged children. In this cross-sectional study, data on each child's SHS exposure and ADHD symptoms and subtypes were collected through questionnaires administered by school teachers to parents, and data were analyzed from September 14, 2020 to December 2, 2020. ADHD symptoms and subtypes (inattention, hyperactivity-impulsivity, and combined) were assessed using the ADHD symptoms and subtypes (inattention, hyperactivity, impulsivity, and combined) were measured based on a validated tool developed from the Diagnostic and Statistical Manual of Mental Disorders (4th edition), and a total of 45,562 participants completed the questionnaire and were included in the study.
Compared to children with no SHS exposure, the odds of having symptoms and subtypes of ADHD were higher in children with constant SHS exposure, exposed from pregnancy through childhood so far. (ORs ranged from 1.46 [95% CI, 1.31-1.62] to 2.94 [95% CI, 2.09-4.13])
Compared with unexposed children, children exposed to SHS were more likely to exhibit ADHD symptoms when exposed in the prenatal period (OR, 2.28; 95% CI, 2.07-2.51), early postnatal period (OR, 1.47; 95% CI, 1.29)
Although the results of this study showed an association between SHS exposure and ADHD symptoms and subtypes, there are several limitations. First, because it was a cross-sectional study, it was not possible to assess the temporality of the results. Second, we used a self-report questionnaire to measure SHS exposure, which may have introduced recall bias and exposure misclassification.
We then used the validated DSM-IV, but were unable to diagnose any cases in this study. Finally, we did not collect data on parental ADHD history, so we cannot rule out the possibility of confounding associations due to these influences. Despite these limitations, the results of the study are noteworthy for their large sample size covering a wide developmental range of children, comprehensive information on SHS exposure across many exposure windows, and several ADHD assessments.
