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

Fleming, M. , Bandyopadhyay, A., McLay, J. S., Clark, D., King, A., Mackay, D. F. , Lyons, R. A., Sayal, K., Brophy, S. and Pell, J. P. (2022) Age within schoolyear and attention-deficit hyperactivity disorder in Scotland and Wales. BMC Public Health, 22, 1070. (doi: 10.1186/s12889-022-13453-w) (PMID:35637502) (PMCID:PMC9150337)

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.

• Item Type: Articles
• Additional Information: The Scottish part of the study was sponsored by Health Data Research UK (grant reference number MR/S003800/1). This Welsh research was funded as part of the ADR Wales programme of work. ADR Wales is part of the Economic and Social Research Council (part of UK Research and Innovation) funded ADR UK (grant ES/S007393/1). This Welsh research was also supported by and the National Centre for Population Health and Well-Being Research (NCPHWR).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Mackay, Professor Daniel and Fleming, Dr Michael and Pell, Professor Jill
• Authors: Fleming, M., Bandyopadhyay, A., McLay, J. S., Clark, D., King, A., Mackay, D. F., Lyons, R. A., Sayal, K., Brophy, S., and Pell, J. P.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > General Practice and Primary Care; College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Public Health
• Journal Name: BMC Public Health
• Publisher: BioMed Central
• ISSN: 1471-2458
• ISSN (Online): 1471-2458
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in BMC Public Health 22: 1070
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
303197		Linking education and health data together to study relationships between various health factors and children's educational and health outcomes	Jill Pell	Medical Research Council (MRC)	MR/S003800/1	HW - Public Health