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Background: Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent childhood disorder. Maternal smoking during pregnancy is a replicated environmental risk factor for this disorder. It is also a robust modifier of gene methylation during the prenatal developmental period. In this study, we sought to identify loci differentially methylated by maternal smoking during pregnancy and relate their methylation levels to various behavioural and physical outcomes relevant to ADHD. Methods: We extracted DNA from blood samples from children diagnosed with ADHD and deeply phenotyped. Genome-wide DNA methylation was assessed using Infinium MethylationEPIC BeadChip. Maternal smoking during pregnancy was self-declared and assessed retrospectively. Results: Our sample included 231 children with ADHD. Statistically significant differences in DNA methylation between children exposed or not to maternal smoking during pregnancy were detected in 3457 CpGs. We kept 30 CpGs with at least 5% of methylation difference between the 2 groups for further analysis. Six genes were associated with varied phenotypes of clinical relevance to ADHD. The levels of DNA methylation in RUNX1 were positively correlated with the CBCL scores, and DNA methylation in MYO1G correlated positively with the score at the Conners rating scale. Methylation level in a CpG located in GFI1 correlated with birthweight, a risk factor for ADHD. Differentially methylated regions were also identified and confirmed the association of RUNX1 methylation levels with the CBCL score. Limitations: The study has several limitations, including the retrospective recall with self-report of maternal smoking during pregnancy as well as the grouping of individuals of varying age and developmental stage and of both males and females. In addition, the correlation design prevents the building of causation models. Conclusion: This study provides evidence for the association between the level of methylation at specific loci and quantitative dimensions highly relevant for ADHD as well as birth weight, a measure that has already been associated with increased risk for ADHD. Our results provide further support to public health educational initiatives to stop maternal smoking during pregnancy., Introduction Attention-deficit/hyperactivity disorder (ADHD) is one of the most common early-onset neurobehavioural disorders, with a worldwide prevalence of 5.9%-7.1% in the school-aged population. (1) It is a complex disorder involving [...]

A growing body of research suggests an association between attention deficit hyperactivity disorder (ADHD) and allergic disorders, but little work has been done to explore the role of external factors such as parental smoking at home in the development of comorbid ADHD and allergic disorders. This study aimed to examine the association between allergic diseases and ADHD adjusted for exposure to parental smoking at home in early adolescents. We recruited 250 male (41.7%) and 350 female (58.3%) adolescents (mean [SD] age, 13.29 [0.52] years) via chain-referral sampling. Their ADHD symptoms were assessed by the parent proxy-report version of the Chinese Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviours (SWAN) rating scale. Data on the participants' history of clinician-diagnosed allergic diseases, family socio-demographics, and parental smoking habit were collected using a parent-completed questionnaire. Regression analyses were performed to examine the associations of interest. The levels of ADHD symptoms were comparable between allergic and non-allergic participants after controlling for child and family demographics and parental smoking at home. Notably, the risk of probable ADHD was particularly high in participants with food allergies (odd ratio = 4.51, p = 0.011) but not in those with allergic rhinitis after adjusting for parental smoking at home. Our findings suggest that second-hand smoke exposure at home is a potential risk factor underlying the link between ADHD and allergic diseases. Current management guidelines should emphasize the importance of early identification and cessation of tobacco smoke exposure for prevention of comorbidity of ADHD and allergic disorders. Clinical Trial Registration (if any): NA., Author(s): Rosa S. Wong [sup.1] [sup.2] [sup.3] , Keith T. S. Tung [sup.1] , Hugo E. Leung [sup.1] , Reena Chow [sup.1] , Gilbert T. Chua [sup.1] , Macro H. [...]

This study aimed to examine possible associations between Attention-Deficit/Hyperactivity Disorder (ADHD) and pregnancy-related, birth-related, developmental, medical, and surgical history characteristics. The sample was derived from a non-referred community sample aged 6 to 14. 91 cases with ADHD and 264 without any psychopathology were compared in terms of psychological and physical problems in pregnancy, mode of delivery, birth complications, developmental stages, injuries, medical and surgical diseases. A semi-structured clinical interview was applied to diagnose the children. ADHD Rating Scale-IV (ADHD-RS-IV) was completed by the parents. Male gender, delay in talking time, and physical injury history predicted increased risks for ADHD. Although having any surgery, and in particular, tonsillectomy did not predict ADHD, inguinal hernia surgery alone predicted an increased risk for ADHD even when controlled for gender. Psychological problems during pregnancy were associated with elevated inattention (IN) and hyperactivity-impulsivity (HI) scores, but not associated with ADHD as a diagnosis. Elevated IN scores but not HI scores were associated with a physical injury history. Although the mode of delivery and physical disease history were not associated with ADHD, asthma increased the likelihood for higher HI scores. The findings have crucial clinical implications that address several points. The findings suggest ADHD may have associations with some negative neurodevelopmental, medical, and surgical history characteristics. The predictivity of inguinal hernia surgery for ADHD might depend on the exposure to general anesthesia at younger ages. Hence, children who had these features should carefully be screened for ADHD., Author(s): Aslihan Esra Yüksel [sup.1] , Nurhak Dogan [sup.2] , Akin Tahillioglu [sup.2] , Öznur Bilaç [sup.3] , Taciser Uysal [sup.4] , Eyüp Sabri Ercan [sup.2] Author Affiliations: (1) grid.8302.9, [...]

This study was conducted to assess this association between early life antibiotic exposure and the risk of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) in later life. The results showed that early life antibiotic exposure was associated with an increased risk of ASD (OR = 1.13, 95% confidence interval (CI): 1.07-1.21) or ADHD (OR = 1.18, 95% CI: 1.1-1.27). However, this association for ASD (OR = 1.04, 95% CI: 0.97-1.11) or ADHD (OR = 0.98, 95% CI: 0.94-1.02) disappeared when data from sibling-matched studies were pooled. The statistically significant association between early life antibiotic exposure and ASD or ADHD in later life can be partially explained by unmeasured genetic and familial confounding factors., Author(s): Hai-ying Yu [sup.1] , Yuan-yue Zhou [sup.2] , Li-ya Pan [sup.1] , Xue Zhang [sup.1] , Hai-yin Jiang [sup.1] Author Affiliations: (1) grid.13402.34, 0000 0004 1759 700X, State Key [...]

We investigated infant's manual motor behaviour; specifically behaviours crossing the body midline. Infants at elevated likelihood of Autism Spectrum Disorder (ASD) and/or Attention Deficit Hyperactivity Disorder (ADHD) produced fewer manual behaviours that cross the midline compared to infants with a typical likelihood of developing these disorders; however this effect was limited to 10-month-olds and not apparent at age 5 and 14 months. Although, midline crossing did not predict ASD traits, it was related to ADHD traits at 2 years of age. We rule out motor ability and hand dominance as possible explanations for this pattern of behaviour, positing that these results may be a consequence of multisensory integration abilities, and the neurobehavioural shift period, in the first year of life., Author(s): Jannath Begum Ali [sup.1] , Tony Charman [sup.2] , Mark H. Johnson [sup.1] [sup.3] , Emily J. H. Jones [sup.1] Author Affiliations: (1) grid.88379.3d, 0000 0001 2324 0507, Centre [...]