Age within schoolyear and attention-deficit hyperactivity disorder in Scotland and Wales

Fleming, Michael; Bandyopadhyay, Amrita; Mclay, James S; Clark, David; King, Albert; Mackay, Daniel F; Lyons, Ronan A; Sayal, Kapil; Brophy, Sinead; Pell, Jill P

Abstract

Background
Previous studies suggest an association between age within schoolyear and attention-deficit hyperactivity disorder (ADHD). Scotland and Wales have different school entry cut-off dates (six months apart) and policies on holding back children. We aim to investigate the association between relative age and treated attention deficit hyperactivity disorder (ADHD) in two countries, accounting for held-back children.

Methods
Routine education and health records of 1,063,256 primary and secondary schoolchildren in Scotland (2009–2013) and Wales (2009–2016) were linked. Logistic regression was used to examine the relationships between age within schoolyear and treated ADHD, adjusting for child, maternity and obstetric confounders.

Results
Amongst children in their expected school year, 8,721 (0.87%) had treated ADHD (Scotland 0.84%; Wales 0.96%). In Wales, ADHD increased with decreasing age (youngest quartile, adjusted OR 1.32, 95% CI 1.19–1.46) but, in Scotland, it did not differ between the youngest and oldest quartiles. Including held-back children in analysis of their expected year, the overall prevalence of treated ADHD was 0.93%, and increased across age quartiles in both countries. More children were held back in Scotland (57,979; 7.66%) than Wales (2,401; 0.78%). Held-back children were more likely to have treated ADHD (Scotland OR 2.18, 95% CI 2.01–2.36; Wales OR 1.70, 95% CI 1.21–2.31) and 81.18% of held-back children would have been in the youngest quartile of their expected year.

Conclusions
Children younger within schoolyear are more likely to be treated for ADHD, suggesting immaturity may influence diagnosis. However, these children are more likely to be held back in countries that permit flexibility, attenuating the relative age effect.

Citation

Fleming, M., Bandyopadhyay, A., Mclay, J. S., Clark, D., King, A., Mackay, D. F., …Pell, J. P. (2022). Age within schoolyear and attention-deficit hyperactivity disorder in Scotland and Wales. BMC Public Health, 22(1), Article 1070. https://doi.org/10.1186/s12889-022-13453-w

• Journal Article Type: Article
• Acceptance Date: May 4, 2022
• Online Publication Date: May 30, 2022
• Publication Date: May 30, 2022
• Deposit Date: May 12, 2022
• Publicly Available Date: May 12, 2022
• Journal: BMC Public Health
• Electronic ISSN: 1471-2458
• Publisher: Springer Science and Business Media LLC
• Peer Reviewed: Peer Reviewed
• Volume: 22
• Issue: 1
• Article Number: 1070
• DOI: https://doi.org/10.1186/s12889-022-13453-w
• Keywords: Public Health, Environmental and Occupational Health
• Public URL: https://nottingham-repository.worktribe.com/output/8046603
• Publisher URL: https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-022-13453-w
• Additional Information: Received: 5 May 2021; Accepted: 3 May 2022; First Online: 30 May 2022; All methods were carried out in accordance with relevant guidelines and regulations. The need for ethical approvals to access Scottish and Welsh data were waived by the NHS West of Scotland Research Ethics Service and the SAIL Databank Information Governance Review Panel (IGRP) respectively. The former confirmed that formal NHS ethics approval was not required for the analyses of the Scottish data since the study involved linkage of routinely collected data with an acceptably negligible risk of identification. The Scottish data were approved by the National Health Service Public Benefit and Privacy Panel and covered by a data processing agreement between Glasgow University and Public Health Scotland and a data sharing agreement between Glasgow University and the education department of the Scottish Government (ScotXed). The Welsh data were approved by SAIL Databank Information Governance Review Panel (IGRP) and the data were analysed under the approved project Wales Electronic Cohort for Children (WECC): Phase 4 (project number 0916).The need for informed consents for Scottish and Welsh data were also waived by the NHS West of Scotland Research Ethics Service and the SAIL Databank Information Governance Review Panel (IGRP) respectively. It was deemed that obtaining informed consent from patients did not apply to our study which involved retrospectively linking and analysing already collected and centrally held routine administrative data comprising anonymised electronic patient records.; : Not applicable.; : All authors declare that they have no competing interests.