Format

Send to

Choose Destination
See comment in PubMed Commons below
J Child Psychol Psychiatry. 2014 Nov;55(11):1244-50. doi: 10.1111/jcpp.12243. Epub 2014 May 12.

Children's relative age in class and use of medication for ADHD: a Danish Nationwide Study.

Author information

1
Clinical Pharmacology, Institute of Public Health, University of Southern Denmark, Odense C, Denmark; Department of Clinical Chemistry & Pharmacology, Odense University Hospital, Odense C, Denmark.

Abstract

BACKGROUND:

Previous studies from North America and Iceland have shown that the youngest children within a grade are up to twice as likely to be diagnosed and treated for attention-deficit/hyperactivity disorder (ADHD) compared with their older classmates. We aimed to investigate whether younger age in class is associated with an increased probability of being prescribed medication for ADHD among school-aged children in Denmark.

METHODS:

We followed all Danish children between 2000 and 2012 from 1st through 6th grade (7-12 years). Among children who started school on their age-assigned grade level, we estimated the prevalence proportion ratio (PPR) of receiving ADHD medication between the youngest children in class (born in October-December) and the oldest in class (born in January-March), specified by grade level, calendar year and gender. As a sensitivity analysis, we added children not on their age-assigned grade level to the main calculations.

RESULTS:

We identified 932,032 eligible children for the main analysis, of whom 17.3% were among the youngest and 26.5% among the oldest in class. In total, 1.2% eligible children filled at least one prescription for ADHD medication in 2000-2012. The average PPR over the study period was 1.08 (95% CI, 1.04-1.12) and remained stable across subgroups and sensitivity analyses. Overall, 40% of children born October-December had entered school a year after their age-assigned grade level.

CONCLUSIONS:

Contrary to previous study results, we observed almost no relative age effect on medication use for ADHD among children in Denmark. We postulate that this may be due to the high proportion of relatively young children held back by 1 year in the Danish school system and/or a generally low prevalence of ADHD medication use in the country.

KEYWORDS:

Attention-deficit hyperactivity disorder; age factors; central stimulants; children; drug utilization evaluation

Comment in

PMID:
24813478
PMCID:
PMC4277337
DOI:
10.1111/jcpp.12243
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley Icon for PubMed Central
    Loading ...
    Support Center