The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Trial ID
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Vitamin D for correcting deficiency in adolescents: a general
practice-based randomised controlled trial
Scientific title
Vitamin D deficient adolescents randomised to 50000 international units (IU) of vitamin D3 given orally monthly or 150000 IU of vitamin D3 given orally 3-monthly or placebo given monthly and 3-monthly, assessed by correcting vitamin D deficiency, feasibility of recruiting adolescents using general practice, and obtaining pilot bone density outcome data.
Secondary ID [1] 282617 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Vitamin D deficiency 289308 0
Condition category
Condition code
Musculoskeletal 289645 289645 0 0

Study type
Description of intervention(s) / exposure
50000 IU vitamin D3 orally monthly or 150000 IU (3 x 50 000 IU tablets) orally 3-monthly for 12 months
Intervention code [1] 287283 0
Treatment: Drugs
Comparator / control treatment
Placebo (tablet) orally monthly and 3-monthly. The placebo consists of a filler called microcrystalline cellulose (C6H10O5)n.
Control group

Primary outcome [1] 289726 0
Correction of vitamin D deficiency which will be assessed by blood test measuring serum 25-hydroxyvitamin D
Timepoint [1] 289726 0
3, 6, and 12 months from commencement of treatment
Secondary outcome [1] 303111 0
Feasibility of using general practice as the setting through which vitamin D deficient adolescents can be identified and treated. This will be assessed by assessing how long it takes to recruit 33 adolescents and keeping track of the number of adolescents contacted, screened and then enrolled in the study.

Timepoint [1] 303111 0
Recruitment and screening
Secondary outcome [2] 303112 0
Obtaining pilot bone density outcome data by measuring bone mineral density (BMD) at the total hip, lumbar spine and femoral neck determined using dual-energy x-ray absorptiometry.
Timepoint [2] 303112 0
12 months from commencement of treatment

Key inclusion criteria
Healthy adolescents aged 15-17 years.

Mild to moderate vitamin D deficiency (serum 25-OHD 12.5-50 nmol/L).

No known severe renal impairment, malabsorption, pregnancy, or lactation.

No clinical signs of rickets.

No reason known to GP to prevent participation or which makes making contact with the young person inappropriate (there may be cases where for reasons of patient confidentiality the GP will not wish a letter to be sent to a young person’s parents for example).
Minimum age
15 Years
Maximum age
17 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Normal vitamin D levels (serum 25-OHD > 50 nmol/L).

Severe vitamin D deficiency (serum 25-OHD < 12.5 nmol/L). These patients will be referred to their GP for assessment and consideration of treatment. We will send a copy of these results together with a letter outlining appropriate treatment advice to the GP.

Known severe renal impairment, malabsorption, pregnancy, or lactation.

Clinical signs of rickets.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 3
Type of endpoint(s)
Statistical methods / analysis
Based on our previous pilot study, we expect near total correction of mild to moderate vitamin D deficiency by a dose equivalent of 300,000IU orally of vitamin D3 over 6 months and that only 16% of children receiving placebo would correct their vitamin deficiency. Assuming 10% drop out (i.e. 10 children remaining in each group at 12 months) and with statistical significance set at p<0.05 (two-tailed), we have power of 0.85 to detect a difference in prevalence of deficiency between each vitamin D supplemented group and placebo of 70% i.e. between 90% of children no longer being deficient in vitamin D groups and 20% of children no longer being deficiency in the placebo group.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 287395 0
Name [1] 287395 0
The Royal Australian College of General Practitioners
Address [1] 287395 0
College House
1 Palmerston Crescent
South Melbourne, Victoria 3205
Country [1] 287395 0
Primary sponsor type
Menzies Research Institute Tasmania, University of Tasmania
17 Liverpool St (Private Bag 23)
Hobart, TAS
Secondary sponsor category [1] 286136 0
Name [1] 286136 0
Address [1] 286136 0
Country [1] 286136 0

Ethics approval
Ethics application status
Ethics committee name [1] 289372 0
Tasmania Health & Medical Human Research Ethics Committee (EC00337)
Ethics committee address [1] 289372 0
Office of Research Services
University of Tasmania
Private Bag 01
Hobart TAS 7001
Ethics committee country [1] 289372 0
Date submitted for ethics approval [1] 289372 0
Approval date [1] 289372 0
Ethics approval number [1] 289372 0

Brief summary
Adolescents are at particular risk of vitamin D deficiency and are also a group who may not take medications regularly. The optimal dosage regimen for adolescents to help them take vitamin D regularly enough to correct deficiency is not known. Therefore the main aim of this study is to test two different vitamin D dosage regimens to see if they can both correct vitamin D deficiency in adolescents. The study will also show whether vitamin D deficient adolescents can be successfully identified through general practice and provide preliminary pilot data on whether correcting vitamin D deficiency results in significant improvements in bone density.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 40518 0
A/Prof Tania Winzenberg
Address 40518 0
Menzies Research Institute Tasmania
17 Liverpool St (Private Bag 23)
Hobart, TAS
Country 40518 0
Phone 40518 0
+61 3 6226 7770
Fax 40518 0
Email 40518 0
Contact person for public queries
Name 40519 0
A/Prof Tania Winzenberg
Address 40519 0
Menzies Research Institute Tasmania
17 Liverpool St (Private Bag 23)
Hobart, TAS
Country 40519 0
Phone 40519 0
+61 3 6226 7770
Fax 40519 0
Email 40519 0
Contact person for scientific queries
Name 40520 0
A/Prof Tania Winzenberg
Address 40520 0
Menzies Research Institute Tasmania
17 Liverpool St (Private Bag 23)
Hobart, TAS
Country 40520 0
Phone 40520 0
+61 3 6226 7770
Fax 40520 0
Email 40520 0