Study period | |||||
---|---|---|---|---|---|
Pre-randomization | Intervention | Post-intervention follow-up | Close-out | ||
TIMEPOINT | Year 1 | 0 | Year 1 | Year 1 | |
Sept – Nov | Sept – March | April – May | |||
Year 2 | Year 2 | Year 2 | |||
Sept – Nov | Sept – March | April – May | |||
Year 3 and 4 | Year 3 and 4 | Year 3 and 4 | Year 4 | ||
Sept – Nov | Sept – March | April – May | June – Aug | ||
INTERVENTIONS: | |||||
‘Standard dose’ 400 IU/day | X | X | |||
‘High dose’ 2000 IU/day | X | X | |||
PROCEDURES: | |||||
Informed consent | X | ||||
Eligibility screen | X | ||||
Randomization | X | ||||
ASSESSMENTS: | |||||
Baseline survey data | X | X | |||
Anthropometrics | X | ||||
25-hydroxyvitamin D serum level | X | X | |||
Laboratory-confirmed URTI | X | ||||
Asthma exacerbations | X | ||||
Follow-up survey data | X | ||||
ANALYSIS | X |