Childhood obesity trials measure a growing child, so the same height and weight mean different things at different ages. They also change a whole household. Capture holds the anthropometry, parent and child questionnaires, session attendance and safety in one study with one audit trail. Build it free in the sandbox, no credit card.
Free sandbox · No credit card · 21 CFR Part 11 aligned
Measurements
Date of measurement
VSDTCAge at visit
AGEYRSRead-only, from date of birth
11.4 years CalculatedHeight
HEIGHTWeight
WEIGHTBMI
BMICalculated from height and weight
26.3 kg/m² CalculatedWaist circumference
WAISTWhat a childhood obesity trial needs from its EDC
The study data
Childhood obesity studies fall into two broad groups. Behavioural and family-based programmes, delivered in clinics, schools or communities, test whether counselling, activity and food changes move a child’s weight. Pharmacological and device studies in adolescents test a product against placebo or usual care, with a safety profile that is read against growth and puberty. Both are commonly judged on a change in BMI z-score, which standardises BMI for age and sex against a reference population. Registered trials report this against CDC age- and sex-specific data, and eligibility is often defined as BMI at or above a percentile cut-off; which growth reference and which cut-off apply is for your protocol to state.
That shapes what the EDC should hold. Do not store only a derived z-score. Store date of birth, sex, date of measurement, height, weight and the measurement conditions (clothing, device used, who measured), and let the analysis programme derive the z-score with the reference named in the plan. Capture calculates BMI from height and weight in the form, shown read-only to site staff, and age from date of birth, so entry errors show up before the statistician finds them. Range edit checks on height and weight can catch a transposed digit, and a check on the change since the previous visit can catch an implausible jump.
Secondary outcomes widen the dataset. Waist circumference, blood pressure (see the vital signs template), fasting glucose and lipids on a laboratory form, body composition on a DXA body composition form, physical activity, screen time and diet are all common candidates. A diet recall can be captured with the 24-hour recall template, and quality of life with the PedsQL template in child and parent versions.
In a family-based trial, there is no pill count. Exposure is how many sessions the family attended, which components were delivered and by whom. Add a repeating session form with date, session type, attendees (child, parent, sibling), duration and a reason for any missed session. Dose of programme is then a count in the export instead of a comment. Fidelity checks, such as a session observer’s rating, can sit on their own form.
Families enrolled
60
Sessions held
12
Median attendance
9 / 12
Months 6 visits overdue
4
Protocol to build
| Protocol element | What the data looks like | Where it lives in Capture |
|---|---|---|
| Eligibility | Date of birth, sex, height, weight, BMI, medical exclusions, medications | Eligibility form with calculated BMI and age |
| Anthropometry | Height, weight, waist, date, device | Vital signs form plus a measurement form; BMI calculated read-only |
| Child and parent questionnaires | Self-report and proxy responses, who answered | Parent-proxy ePRO and a child version in built-in ePRO |
| Programme delivery | Session date, type, attendees, duration, missed reason | Repeating session form |
| Randomization | Arm, stratification (for example age band, sex, severity) | Randomization, including cluster designs where schools or clinics are randomized |
| Labs and blood pressure | Glucose, lipids, liver enzymes, blood pressure | Laboratory eCRF with local reference ranges |
| Safety | AE term, grade, seriousness, relationship, action | Adverse event form |
Capture records the data your protocol defines. Growth references, percentiles and analysis rules are set in the statistical plan.
Upload the protocol, let the AI draft the visits and forms for review, then enter three visits for a practice child and check how the calculated BMI and edit checks behave. Free sandbox.
Children in research
Children cannot give legal consent, so paediatric studies combine permission from a parent or guardian with the child’s own assent, scaled to age and maturity. Capture’s eConsent supports an on-screen signature after an email one-time code, an optional witness, a Legally Authorized Representative signature and investigator countersignature; the document is fully executed only after that. A paediatric assent template is available as a starting layout. Your ethics committee decides ages and wording. See legally authorized representative consent and the broader EDC for paediatric trials page.
Weight is a sensitive topic for a child. Protocols often ask for measurement in private, a neutral way to report results and language that avoids blame. That belongs in the study procedures, but the EDC supports it. Role-based access keeps participant names with site coordinators and coded IDs with researchers, and PII segregation is enforced in the database. Teams that give feedback to families should decide in advance which results are returned and by whom, and record that decision with the consent materials.
Safety depends on the intervention. A behavioural programme usually has few related events, but injuries during activity sessions and any psychological distress should be captured. For an adolescent drug study, growth velocity, pubertal staging and mood or suicidality screening are commonly followed. Pubertal staging can be a simple site form with a date and a rater; the validated instruments you choose stay licensed through your own documents.
Build sequence
A realistic order of work for an academic or sponsor-led team.
Upload the protocol (PDF, DOCX or DOC) and let the AI study builder propose the schedule and forms. Nothing is saved until a person reviews it.
Date of birth, sex, height, weight, waist and device, with calculated BMI and age and range checks on each value.
A child version and a parent-proxy version as phone questionnaires, with the respondent recorded.
A repeating session form with attendees and missed reasons, plus randomization if the design needs it.
Run a practice family through screening, three sessions and a six-month visit, check the export, approve the forms and start the paid live phase when real participants enrol.
Sites and exports
Obesity trials often run in several clinics or schools. Capture supports QR-code enrolment, site-level participant numbering, a site coordinator portal and by-site filtering and exports; see multi-site clinical trial management and QR code participant enrollment. Pragmatic designs that compare programmes in routine care are covered under pragmatic clinical trial software.
Exports come as CSV or Excel with an automatic data dictionary, and CDISC SDTM export gives SAS XPT datasets with Define-XML; see export EDC data to R, SAS and SPSS. Sample size for a continuous outcome such as BMI z-score can be started with the two means sample size calculator.
Before first participant
Which reference and cut-off define eligibility and the primary outcome, written into the statistical plan.
Device, clothing, who measures, how many readings and how a repeat is recorded.
Ages, wording and format approved by the ethics committee and tested in the sandbox.
Which questionnaires are child-completed, which parent-completed, and from what age.
What counts as a session attended and how missed sessions are recorded.
Wide CSV with data dictionary opened in the statistics package.
Capture calculates BMI and age in the form. The z-score or percentile is derived in analysis against the growth reference your statistical plan names, using the date of birth, sex, height and weight in the export.
Yes. Build a child version and a parent-proxy version, each opened from a secure link on a phone, and record who answered.
With a repeating session form: date, type, attendees, duration and a reason for any missed session. Dose of programme then exports as data.
Yes. Cluster designs are supported through randomization in the same platform; see the cluster-randomized trials page.
Parent permission and child assent are handled with eConsent, which supports an on-screen signature after an email code, a Legally Authorized Representative signature and investigator countersignature. Your ethics committee sets ages and wording.
Capture provides 21 CFR Part 11-aligned controls: a field-level audit trail, electronic signatures and role-based access. Compliance is shared with the sponsor’s own validated use of the system. This is not legal advice.
Keep exploring
EDC for paediatric clinical trials
Assent, proxy reporting and growth-sensitive safety.
PedsQL eCRF template
Child and parent quality-of-life form structure.
Parent-proxy ePRO template
A questionnaire answered by a parent.
EDC for cluster randomized trials
Randomizing schools or clinics.
Capture ePRO
Questionnaires, reminders and completion windows.
Free sandbox with every feature. No credit card, and you pay only when you go live with real participants.