A vitamin D conference, “Vitamin D — Minimum, maximum, optimum” was held in Warsaw, Poland, Oct. 19-20, 2012, to develop guidelines for vitamin D for Central Europe. It was organized by Pawel Plodowski and Elzbieta Karczmarewicz. There were 550 attendees from Poland and other countries. The international scientific committee included:
Many other countries were represented including Australia, Finland, Kenya, Norway, Russia, and Scotland. Several dozen posters were also presented.
Non-skeletal effects including autoimmune diseases including multiple sclerosis and rheumatoid arthritis, cancer, diabetes mellitus, cardiovascular disease, chronic kidney disease, diabetes mellitus, immunity, musculoskeletal defects, rickets and adverse pregnancy outcomes were discussed. Adverse effects of high serum 25-hydroxyvitamin D [25(OH)D] were discussed with the conclusion that there is little verified evidence of harm below a daily intake of 10,000-20,000 IU/d vitamin D3 or serum 25(OH)D concentrations above 100 ng/ml. Graham Carter of DEQAS (Vitamin D External Quality Assessment Scheme) discussed the accuracy of 25(OH)D assays worldwide.1 Papers by many speakers were published in two Polish journals, Standardy Medyczne/Pediatria (Standards of Medicine/Pediatrics) 2012;9(5): and Postepy Nauk Medycznych (Progress in Medicine) 2012;XXV(3). Henry Lahore is making many of the papers available at www.vitamindwiki.com in html format, which permits translation into any of 57 languages.
The committee included consideration of observational studies in addition to randomized controlled trials (RCTs), a significant contrast to the Institute of Medicine (IOM) which considered only RCTs and set the recommended 25(OH)D concentration at 20 ng/ml. Although Glenville Jones made the case for the IOM position here, that proposal received very little support from the scientific committee or others at the conference.
The primary recommendation was that the 25(OH)D concentration should be between 30-60 ng/ml. A paper by Lorenc et al.  suggested the range be set at 30-80 ng/ml, but the conference decided there is a lack of evidence for higher concentrations for the time being. Committee members voted on many issues prior to the meeting, with the results presented at the end of the conference.
Given the care in assembling a scientific committee with a number of the world’s leading vitamin D researchers, the recording of the presentations, the publication of speakers’ reviews, and the very large attendance, the recommendations from this conference should be considered and receive widespread acceptance.
As an aside, the reason that the IOM considered only RCTs is that they were following the principles of evidence based medicine. I prepared a paper for this conference that applied Hill’s criteria for causality to vitamin D and cancer .4 Many factors and studies can be considered with such criteria. You can read his original paper in its entirety.
For those interested in some of the short-comings of evidence based medicine, see Tarnished Gold, the Sickness of Evidence Based Medicine by Steve Hickey and Hilary Roberts, published in 2011. I believe that the Hill criteria are more suitable for public health recommendations than those relating evidence based medicine based primarily on RCTs.