Reasons to disqualify a Vitamin D trial

The 4 methodological reasons leading to a disqualification of a vitamin D trial.

1. Before the application of vitamin D, the vitamin D level was not determined.
2. There was no proof that improved vitamm D levels were reached by therapy
3. After the intitial therapy there was no long-term treatment to maintain the improved vitamin D level
4. There was no loading dose to fill the vitamin D storage

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See also VitaminDWiki

• Vitamin D clinical trials should be based on Vitamin D tests – Aug 2017 co-authored by Henry Lahore
  • Additional points to consider

1. Seek participants with low baseline serum 25(OH)D values.
2. Use vitamin D3, not vitamin D2 and at sufficiently high doses, 1000–4000 IU/d.
3. Consider giving a modest loading dose of vitamin D3 to reach target 25(OH)D concentrations rapidly .
4. Measure baseline serum 25(OH)D concentrations and repeat at suitable intervals to assess compliance and the achievement of target 25(OH)D values (e.g., using blood spot assays, where acceptable, affordable, convenient, and sufficiently accurate).
5. If calcium and magnesium are given, give them in both RCT arms .
6. Monitor participants’ UVB exposure as well as dietary and supplemental intakes of vitamin D3 and potential confounders, including obesity and genetic variants.
7. Allow for the natural history of disease development in planning RCT duration and dosing, and for subject age.
8. Analyze results in terms of 25(OH)D values at baseline, at completion, and at intervals before disease diagnosis, rather than solely with vitamin D3 dose.
9. Carefully consider vitamin D3 dosing interval with respect to compliance and physiological effect.
10. If, for ethical reasons, participants in the control are given 400 IU/d vitamin D3, the resulting increase in 25(OH)D concentration should be factored into the selection of participants and into outcome analyses.

• Guidelines for optimizing design and analysis of clinical studies of nutrient effects – Jan 2014
  • Rules for individual clinical studies of nutrient effects.
• 1. Basal nutrient status must be measured, used as an inclusion criterion for entry into study, and recorded in the report of the trial.
• 2. The intervention (i.e., change in nutrient exposure or intake) must be large enough to change nutrient status and must be quantified by suitable analyses.
• 3. The change in nutrient status produced in those enrolled in the trials must be measured and recorded in the report of the trial.
• 4. The hypothesis to be tested must be that a change in nutrient status (not just a change in diet) produces the sought-for effect.
• 5. Conutrient status must be optimized in order to ensure that the test nutrient is the only nutrition-related, limiting factor in the response.