Systematic review and meta-analysis:relative age in attention-deficit/ hyperactivity disorder and autism spectrum disorder

Frisira, Eleni; Holland, Josephine; Sayal, Kapil

Abstract

Youngest students in their class, with birthdates just before the school entry cut-off date, are overrepresented among children receiving an Attention-Deficit/Hyperactivity Disorder (ADHD) diagnosis or medication for this. This is known as the relative age effect. This systematic review and meta-analysis summarises the evidence on the influence of relative age on ADHD symptoms, diagnosis and medication prescribing. As no review to date has investigated the association with autism spectrum disorder (ASD) diagnosis, this is also examined. Following prospective registration with PROSPERO, we conducted a systematic review according to the PRISMA guidelines. We searched seven databases: Medline, Embase, PsycInfo, Web of Science Core Collection, ERIC, Psychology and Behavioural Sciences Collection, and Cochrane Library. Additional references were identified from manual search of retrieved reviews. We performed a meta-analysis of quantitative data. Thirty-two studies were included, thirty-one investigated ADHD and two ASD. Younger relative age was associated with ADHD diagnosis and medication, with relative risks of 1.38 (1.36–1.52 95% CI) and 1.28 (1.21–1.36 95% CI) respectively. However, risk estimates exhibited high heterogeneity. A relative age effect was observed for teacher ratings of ADHD symptoms but not for parent ratings. With regard to ASD, the youngest children in their school year were more likely to be diagnosed with ASD. This review confirms a relative age effect for ADHD diagnosis and prescribed ADHD medication and suggests that differences in teacher and parent ratings might contribute to this. Further research is needed on the possible association with ASD.

Citation

Frisira, E., Holland, J., & Sayal, K. (2024). Systematic review and meta-analysis:relative age in attention-deficit/ hyperactivity disorder and autism spectrum disorder. European Child and Adolescent Psychiatry, https://doi.org/10.1007/s00787-024-02459-x

• Journal Article Type: Review
• Acceptance Date: Apr 29, 2024
• Online Publication Date: May 20, 2024
• Publication Date: 2024
• Deposit Date: May 2, 2024
• Publicly Available Date: May 20, 2024
• Journal: European Child and Adolescent Psychiatry
• Print ISSN: 1018-8827
• Electronic ISSN: 1435-165X
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1007/s00787-024-02459-x
• Keywords: Relative age, Autism, ADHD
• Public URL: https://nottingham-repository.worktribe.com/output/34345742
• Publisher URL: https://link.springer.com/article/10.1007/s00787-024-02459-x
• Additional Information: Received: 30 November 2023; Accepted: 29 April 2024; First Online: 20 May 2024; : ; : The authors declare no competing interests.; : The authors have no conflicts of interest to disclose.