| 1. Study design appropriate? |
Ambiguously described, obviously bias inducing or unsuitable for the objectives and stated conclusions |
Possibly restricting but reflected in the scope of the objectives and the stated conclusions |
Planned to minimise bias and allow generalisability beyond the immediate scope of the objectives |
| 2. Are CONSORT guidelines followed? |
Not described, not followed or poorly adherent |
CONSORT report presented but some data missing |
Full adherence to CONSORT guidelines |
| 2. Adequate description of study participants? |
Little or no information given |
Incl/excl and other criteria such as term/ pre-term/ small for gestational age baby given in some way; at least two useful measures including measure of vitamin D status, ethnicity |
Incl/excl and other criteria such as term/ pre-term/ small for gestational age baby given in some way; at least three useful measures including measure of vitamin D status, ethnicity with measures of precision |
| 4. Is randomisation adequate? |
No randomisation or not discussed |
Some attempt at randomisation |
Robust randomisation |
| 5. Is there placebo control and is blinding adequate? |
Not controlled, not adequate or not discussed |
Placebo control, either not blinded or single blinded |
Placebo control, double-blinded |
| 6. Are details of the study medication given? |
No details |
Some detail e.g. “vitamin D 1000 iu per day” |
Full details including D2 or D3, manufacturer, GMP compliant, full regimen. |
| 7. Is change in maternal vitamin D status measured? |
N/A |
No |
Yes |
| 8. Are details of the assay given? |
No details |
Some details e.g. Diasorin RIA |
Fully detail-type, manufacturer, precision, D2/D3 pick up. |
| 9. Measurements of outcomes reliably ascertained? |
Inadequately explained or obviously unsuitable |
Adequate description and reliability/suitability of at least one of the following: instruments, technique/ definition/protocol, people, place |
Detailed description and reliability of one and at least adequate description of the others |
| 10. Measurements of later outcomes objective? |
Subjective measure, eg bone or muscle pain, wheezing |
Ascertained from researcher examination |
Objective measure e.g. DXA, bone biopsy, lung function tests |
| 11. Measures of vitamin D intake/ 25(OH)-vitamin D level, bone outcomes, e.g. BMC rounded? |
Measures categorised or rounded very roughly, or if any clear evidence of rounding exists without explanation in the text |
Yes, but not by much |
No information given and no obvious reason to suspect rounding has occurred; or explicitly stated that measurements were not rounded |
| 12. Consideration for the effects of important confounding factors? (e.g. season, sunlight exposure, calcium intake, maternal compliance, infant feeding) |
One factor controlled for in tables, nothing for the others (NB whether they were measured or not is irrelevant) |
Most factors controlled for in tables, or fewer if one or more is adjusted for in regression |
Most factors adjusted for in regression |
| 13. What proportion of the cohort completed the trial? |
% FU is not given, unclear, or low (below 70%) |
% FU is low to average (70-90%) |
% FU is high (over 90%) |
| 14. Info on non-participants |
Very little or no information, or information given that is adequate but suggests a serious potential for bias |
Adequate information given, or information given that is very clear but suggests a moderate potential for bias |
Above average information given, none of which suggests a potential for bias |
| 15. Analysis rigorous and appropriate? |
No statistical analyses carried out (just tables or description) |
Appropriate statistical techniques but no mention of whether intention to treat or pre protocol |
Appropriate statistical techniques and intention to treat primary analysis |
| 16. Sample size |
Extremely ambiguous, not given, or small (under 100) |
Average (100 to 250) |
Large (over 250) |
