( PDF ) Rev Osteoporos Metab Miner. 2021; 13 (2): 102
To the editors,
We read with interest the position paper of the Spanish Society for Bone Research and Mineral Metabolism (SEIOMM) on COVID-19 and vitamin D, recently published in your journal . This document helps clarify the role of vitamin D in this infectious disease. One of its conclusions caught our attention. In the final section on the risk/benefit ratio of administering vitamin D, it stated that “it is considered that the administration of 10,000 IU/day of cholecalciferol or 4,000 IU/day of calcifediol is safe”. This assertion is bibliographically referenced with a review on the benefit-risk balance of vitamin D by Bischoff-Ferrari et al.  In this paper, an evaluation of the effectiveness and safety of several clinical trials in which cholecalciferol (vitamin D3) [mostly] or ergocalciferol (vitamin D2). In no case does the review collect clinical data generated from calcifediol supplementation, so including calcifediol in the phrase seems to us to generate some confusion.
Actually, the authors’ thesis of the cited article is that, based on the scientific evidence available at the date of publication, it could be concluded that 10,000 IU of cholecalciferol/day may be the maximum safety limit for supplementation with vitamin D (it is even said that there is no robust evidence that even higher doses cause severe hypercalcaemia and/or vascular calcifications) and that doses of up to 4,000 IU of cholecalciferol/day are safe, without mentioning anything about calcifediol as an alternative supplementation with vitamin D. We would like to show that we agree with the conclusions of Bischoff-Ferrari et al.  Therefore, we consider that the statement made in the SEIOMM document on vitamin D and COVID- 19 regarding the safety of vitamin D should refer only to cholecalciferol.
López-Medrano F, Costa-Segovia R, Díaz-Pedroche C
Internal Medicine Service. Research Institute i + 12.
University Hospital October 12. Madrid (Spain).
Medical Department. School of Medicine. Complutense University of Madrid (Spain)
1. Pérez Castrillón JL, Casado E, Corral Gudino L, Gómez Alonso C, Peris P, Riancho, JA. COVID-19 y vitamina D. Documento de posición de la Sociedad Española de Investigación Ósea y del Metabolismo Mineral (SEIOMM). Rev Osteoporos Metab Miner. 2020;12(4):155-9.
2. Bischoff-Ferrari HA, Shao A, Dawson-Hughes B, Hathcock J, Giovannucci E, Willett WC. Benefit-risk assessment of vitamin D supplementation. Osteoporos Int. 2010;21(7):1121-32.
We have read with interest the letter by Lopez-Medrano et al. regarding the SEIOMM Position Paper on COVID and vitamin D. They are correct when they indicate that the article by Bishoff-Ferrari et al.  assesses the effectiveness and safety of several clinical trials in which cholecalciferol (vitamin D3) [mostly] or ergocalciferol (vitamin D2) was used, the dose being 10,000 IU daily, the maximum safety limit for supplementation with vitamin D. The maximum dose of 25-hydroxyvitamin D that has been indicated is determined by the difference in potency between the two supplements, 2 to 4 times more potent than calcifedio  . The equivalence recently reported by Rizoli , 10 micrograms of calcifediol (600 IU)/day would equal 1,200 IU of cholecalciferol. The document presented is not a systematic review and has a limited number of citations, so a generic citation was preferred.
Internal Medicine Service. Rio Hortega University Hospital.
1. Bischoff-Ferrari HA, Shao A, Dawson-Hughes B, Hathcock J, Giovannucci E, Willett WC. Benefit-risk assessment of vitamin D supplementation. Osteoporos Int. 2010;21(7): 1121-32.
2. Quesada-Gomez JM, Bouillon R. Is calcifediol better than cholecalciferol for vitamin D supplementation? Osteoporos Int. 2018;29(8):1697-711.
3. Rizoli R. Vitamin D supplementation: upper limit for safety revisited? Aging Clin Exp Res. 2021;33:19-24.