Age Groups, and Why They Matter
Part of Pediatric Trials: Why children need their own research.
About 3 minutes. Free, in your language, no account needed.
This is general education about clinical research — not medical advice, and not a way to join a study. Talk to your own doctor about your situation.
"Children" covers an enormous range. A newborn and a sixteen-year-old have almost nothing in common medically, and very little in common in any other way either.
Research handles this by dividing childhood into age groups.
The groups used in international guidance
ICH E11 sets out categories, while saying clearly that any classification is somewhat arbitrary and that the divisions are not rigid lines. The categories it lists are:
- Preterm newborn infants
- Term newborn infants — 0 to 27 days
- Infants and toddlers — 28 days to 23 months
- Children — 2 to 11 years
- Adolescents — 12 to 16 or 18 years, depending on the region
That last point is worth noticing. Where adolescence ends for research purposes is not the same everywhere, because it follows regional law.
Why the divisions exist
Two reasons.
Biology. How a body handles a medicine changes fastest in the earliest weeks and months of life, which is why the youngest categories are the narrowest. A newborn at three days old and one at three weeks old can differ meaningfully.
Everything else. Consent and assent, how a procedure is experienced, how information should be explained, what a study visit does to a day — all of these differ by age as much as biology does.
Adolescents in particular
ICH E11 has practical observations about adolescents that most parents will recognize.
It notes that adolescents are taking on responsibility for their own health and medication, that keeping to a treatment plan can be a particular problem — especially where a medicine affects appearance — and that use of alcohol, tobacco and unprescribed drugs should be specifically considered. It also notes that it may be appropriate to study adolescents in centers skilled in caring for this age group.
None of that is a criticism of teenagers. It is a recognition that an adolescent is an emerging adult with their own views, and that a study which ignores that will not work.
What this means in practice for your child
Your child sits in an age group, and that shapes:
- whether a particular study is open to them at all
- what dose or formulation is being studied
- how information should be given to them
- whether their assent is sought, and how
- what is likely to be reasonable to ask of them at visits
If a study covers a wide age range, it is fair to ask what is different for a child of your child's age specifically — because studies are often designed with different arrangements for different age groups within the same protocol.
In short
- Childhood is divided into age groups for research: preterm and term newborns, infants and toddlers, children 2 to 11, and adolescents to 16 or 18 depending on the region.
- The divisions exist because both biology and everything else change with age, fastest in the first months.
- International guidance treats these categories as useful rather than rigid.
- Guidance recognizes adolescents as emerging adults with their own priorities.
- If a study spans a wide age range, ask what applies to a child of your child's age.