Key Question 3. What is the association between serum 25(OH)D concentrations or calcium balance and clinical outcomes?
Key Question 4. What is the effect of vitamin D or combined vitamin D and calcium intakes on serum 25(OH)D concentrations?
Key Question 5. What is the association between serum 25(OH)D concentrations and surrogate or intermediate outcomes?
The review focused on electronic searches of the medical literature (1969–April 2009) to identify publications addressing the aforementioned questions. One hundred and sixty-five primary articles and 11 systematic reviews that incorporated more than 200 additional primary articles were systematically reviewed, and each was rated on quality and used to assess the strength of evidence for each outcome.
The methods and results chapters of the AHRQ-Tufts evidence review are reprinted below. The report in its entirety, including appendices and evidence tables, can be accessed and viewed at http://www.ahrq.gov/clinic/tp/vitadcaltp.htm.