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. 2016 Sep 5;2016(9):CD011511. doi: 10.1002/14651858.CD011511.pub2

Jensen 2016.

Methods Single‐centre, double‐blind, randomised, placebo‐controlled trial of 6 months’ duration. Concomitant asthma medications were not discontinued during the trial, and analysis was by intention‐to‐treat. There was no run‐in period. The trial was a pilot study, powered to compare the proportion of participants achieving serum 25(OH)D concentration ≥ 75 nmol/L. Target enrolment was 17 per arm, actual enrolment was 11 per arm; enrolment was discontinued on receipt of funding for the substantive trial for which this was the pilot
Participants Participants (n = 22) were recruited from the asthma clinic, hospital wards, and emergency department of the Sainte‐Justine University Health Centre, Montreal, Canada, and randomised to intervention vs control arms of the study in equal numbers. Baseline characteristics were well matched, other than an excess of eczema among participants randomised to vitamin D3 vs placebo.
Inclusion criteria:

  1. Age 1 to 5 years.

  2. Physician‐diagnosed asthma, based on clinical signs of airflow obstruction and reversibility.

  3. URTIs as the main exacerbation trigger, reported by parents.

  4. ≥ 4 parent‐reported URTIs in the past 12 months.

  5. ≥ 1 exacerbation requiring oral corticosteroids in the past 6 months or ≥ 2 in the past 12 months.


Exclusion criteria:

  1. Extreme prematurity (< 28 weeks' gestation).

  2. "High risk of vitamin D deficiency".

  3. Other chronic respiratory disease.

  4. Disordered calcium or vitamin D metabolism.

  5. Oral medications interfering with vitamin D metabolism.

  6. Vitamin D supplementation greater than 1000 IU/day in the past 3 months.
Interventions Active intervention (n = 11): 100,000 IU vitamin D3 oral bolus at baseline, followed by 400 IU vitamin D3 IU orally daily.
Control intervention (n = 11): oral placebo at baseline, followed by 400 vitamin D3 IU orally daily.
Mean serum 25(OH)D concentration, intervention arm: 62 nmol/L (baseline), 157 nmol/L (10 days)
Outcomes Primary outcome:
The mean group change in total serum 25(OH)D from baseline to 3 months.
Secondary outcomes:

  1. The proportion of children with total 25(OH)D ≥ 75 nmol/L (30 ng/mL) at 3 months and in total 25(OH)D values over 6 months.

  2. The proportion of children with hypercalciuria (urinary calcium: creatinine ratio (Ca:Cr) > 1.25 (1 to 2 years) and > 1 (2 to 5 years) mmol/mmol) at any time point.

  3. Serum calcium, phosphorus, and alkaline phosphatase (ALP).

  4. Event rates for exacerbations requiring rescue oral corticosteroids (documented in medical or pharmacy records or both).
Notes Note that low‐dose vitamin D was administered to participants in both intervention and control arms of this trial. Unpublished full text obtained from corresponding author. No conflict of interest identified. Funding: Thrasher Research Fund
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Computer‐generated random sequence
Allocation concealment (selection bias) Low risk Group assignment, recorded on a sequentially numbered list, was allocated by the Sainte‐Justine Hospital Research Pharmacy, which held the randomisation code. To maintain blinding, the intervention and placebo dose were identical in colour, appearance, volume, taste, and packaging. All research personnel, physicians, nurses, participants and their parents were blinded to group allocation. The code was not broken until the study trial was complete (information from principal investigator)
Blinding of participants and personnel (performance bias) 
 All outcomes Low risk Double blind, placebo controlled
Blinding of outcome assessment (detection bias) 
 All outcomes Low risk Double blind, placebo controlled
Incomplete outcome data (attrition bias) 
 All outcomes Low risk 21/22 participants were included in analysis of primary outcome
Selective reporting (reporting bias) Low risk All prespecified primary and secondary outcomes were reported in the main paper. All exploratory/additional outcomes were also reported, with the exception of the duration of exacerbations and viral infections and the severity of exacerbations (due to poor questionnaire completion rate, as well as space restrictions for the manuscript). The additional outcome of cytokine profile is to be reported separately (information from principal investigator; original study protocol was not obtained)
Other bias Low risk Nil. Information on risk of bias for this trial relates to unpublished data