| Characteristic |
Beser 2004 |
Du 2004 |
Duhamel 2000 |
Strand 2002/2003 |
| Intervention 1 (I1) / intervention 2 (I2) / control 1 (C1) |
I1. vitamin D 400 IU/day per os
C1. no placebo or other intervention |
I1: fortified milk, averaged calcium 245 mg/day per os
I2: fortified milk, averaged calcium 245 mg/day per os, vitamin D3 133 IU/day per so
C1: no placebo or other intervention |
I1. vitamin D3 100,000 IU every 3 months per os
C1. placebo |
I1: promoting of exclusive breastfeeding from birth, supplementation of solid foods at age 5 months, weaning at 12 to 18 months, vitamin D 300 IU/day per os during the first 12 months, calcium 378 mg/day per os from age 5 months to 24 months
C1: no placebo or other intervention. |
| Randomised controlled clinical trial (RCT) |
N |
Y |
Y |
Y |
| Controlled clinical trial |
?
(presumed Y) |
N |
N |
N |
| Prospective cohort study |
N |
N |
N |
N |
| Method of randomisation (specify) |
N/A |
? |
? |
? |
| Unit of randomisation (individuals, cluster ‐ specify) |
N/A |
cluster (pupils of matched 3 x 3 schools) |
individuals |
cluster (children of 16 matched villages ) |
| Randomisation stratified for centres |
N/A |
N/A |
? |
N/A |
| Randomisation ratio |
N/A |
? |
? |
?
(intervention group: 14 villages, control group: 2 villages) |
| Concealment of allocation (specify) |
N/A |
? |
? |
? |
| Study population representative of population |
Y |
? |
?
(recruited from hospital) |
Y |
| Method of selection of controls (specify) (*) |
N/A |
N/A |
N/A |
N/A |
| Patients in different groups form same population (*) |
N/A |
N/A |
N/A |
N/A |
| Exposed/unexposed over same period of time (*) |
N/A |
N/A |
N/A |
N/A |
| Ascertainment of group determination (specify) (*) |
N/A |
N/A |
N/A |
N/A |
| Ascertainment of outcome (specify) |
direct measurement |
direct measurement |
direct measurement |
direct measurement |
| Stated blinding (open; single, double, triple blind) |
? |
? |
double |
? |
| Actual blinding: participant/parents |
N/A |
? |
Y |
N/A |
| Actual blinding: caregiver / treatment administrator |
N/A |
? |
? |
N/A |
| Actual blinding: outcome assessor |
? |
? |
? |
N |
| Actual blinding: others |
? |
? |
? |
? |
| Blinding checked: participant |
? |
? |
? |
? |
| Blinding checked: caregiver / treatment administrator |
? |
? |
? |
? |
| Blinding checked: outcome assessor |
? |
? |
? |
? |
| Primary endpoint defined |
Y |
N |
N |
Y |
| [n] of primary endpoint(s) |
1 |
? |
? |
1 |
| [n] of secondary endpoints |
0 |
? |
? |
2 |
| Total [n] of endpoints |
1 |
12
(no distinction made between primary and secondary outcomes) |
8
(no distinction made between primary and secondary outcomes) |
3 |
| Prior publication of study design |
? |
? |
? |
? |
| Power calculation |
? |
? |
? |
? |
| [n] participants per group calculated |
? |
? |
? |
? |
| Intention‐to‐treat analysis (ITT) |
Y
(no summary statistic in analysis) |
Y
(no summary statistic for rickets in analysis) |
Y
(no summary statistic for rickets in analysis) |
N
(based on analysed patients) |
| Per‐protocol‐analysis |
N |
N |
N |
N
(based on analysed patients) |
| ITT defined |
N |
N |
N |
N |
| Dealing with missing data |
? |
? |
? |
?
(imputing for birth weight which is not relevant for this review) |
| [n] of screened participants (I1/ I2 / C1 / total) |
? |
? |
? |
? |
| [n] of randomised/included participants (for primary endpoint) |
I1: 302
C1: 374 |
I1: 238
I2: 260
C1: 259 |
I1: 32
C1: 34 |
Total: 259 |
| [n] of participants finishing the study |
I1: 293
C1: 369 |
I1: 209
I2: 242
C1: 247 |
I1: 32
C1: 31 |
Total: 245 |
| [n] of patients analysed (for primary endpoint) |
no summary statistic provided |
no summary statistic for rickets provided |
no summary statistic for rickets provided |
I1: 183
C1: 46
Total: 229 |
| Description of discontinuing participants |
N |
Y |
N |
N |
| Drop‐outs (reasons explained) |
N |
Y |
N |
N |
| Withdrawals (reasons explained) |
N |
Y |
N |
N |
| Losses‐to‐follow‐up (reasons explained) |
N |
Y |
N |
N |
| [n] of participants who discontinued |
14 |
59 |
3 |
14 |
| [%] discontinuation rate |
2 |
8 |
5 |
5 |
| Discontinuation rate similar between groups |
Y |
Y |
Y |
Y |
| Differences [n] calculated to analysed patients |
N/A |
N/A |
N/A |
N/A |
| Adjustment for multiple outcomes / repeated measurements |
N/A
no summary statistic provided |
Y
no summary statistic for rickets provided |
N/A
no summary statistic provided |
Y |
| Baseline characteristics: clinically relevant differences |
? |
? |
? |
Y
(more preterm born children in intervention group) |
| Treatment identical (apart from intervention) |
? |
? |
? |
? |
| Compliance measured |
? |
Y |
Y |
Y |
| Other important covariates measured (specify) |
? |
? |
? |
? |
| Co‐morbidities measured |
? |
? |
? |
? |
| Co‐medications measured |
? |
? |
? |
? |
| Different length of follow‐up (taken into account) (*) |
N/A |
N/A |
N/A |
N/A |
| Loss of study patients taken into account |
Y |
Y |
Y |
Y |
| Specific doubts about study quality |
N |
N |
N |
N |
| Funding: commercial |
? |
N |
? |
N |
| Funding: non‐commercial |
? |
Y |
? |
Y |
| Publication status: peer review journal |
Y |
Y |
Y |
Y |
| Publication status: journal supplement |
N |
N |
N |
N |
| Publication status: abstract |
N |
N |
N |
N |
| Publication status: other |
N |
N |
N |
N |
| Symbols & abbreviations: Y = yes; N = no; ? = unclear; N/A = not applicable; I = intervention; C = control
(*) for prospective cohort studies only |
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