Youngest in class more likely to have depression, intellectual disability, ADHD

  • JAMA Pediatrics

  • International Clinical Digest
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Takeaway

  • Children who are the youngest in their class are significantly more likely to be diagnosed with depression, an intellectual disability, and/or ADHD than the oldest children in the class.

Why this matters

  • Although prior studies have examined the link between younger relative age within the school year and ADHD and intellectual disability, this study is among the first to focus on the association between younger age and mental health.

Study design

  • Population-based cohort study identified 1,042,106 children (aged 4-15 years) from the Clinical Practice Research Datalink primary care records, United Kingdom (July 2017-January 2019).
  • Funding: None.

Key results

  • 1,040,072 children were followed-up for a median of 3.3 (interquartile range, 1.4-6.4) years.
  • Children born in the last quarter (the youngest) vs those born in the first quarter showed higher risks (Ptrend<.01 for: style="list-style-type:circle;">
  • intellectual disability (aHR, 1.30),
  • ADHD (aHR, 1.36), and
  • depression (aHR, 1.31).
  • Intermediate risks for intellectual disability, ADHD, and depression, respectively, were noted with children born in the:
    • second quarter (HRs: 1.06, 1.15, and 1.05) and
    • third quarter (HRs: 1.20, 1.31, and 1.13).
  • Limitations

    • Exact date of birth was unavailable.

    Coauthored with Chitra Ravi, MPharm