NICE response to Vitamin D correspondence
In response to correspondence from Dr Ellen Grant (2 July 2020; https://www.bmj.com/content/369/bmj.m2503/rr-5) and Professor Peter Cobbold (20 June 2020; https://www.bmj.com/content/369/bmj.m2475/rr) on the NICE rapid evidence summary on vitamin D for COVID-19 (29 June 2020), we would like to clarify the following.
First, the authors appear to have misunderstood the role that NICE plays in clinical research. The remit of NICE is not to conduct scientific trials, but to produce guidance and advice for health, public health and social care practitioners based on evidence, and the expert interpretation of that evidence for UK clinical practice.
Second, the authors may have missed the description in the scope that stated the purpose of the NICE evidence summary on vitamin D for COVID-19 (1) was to review the best available evidence on the effectiveness and safety of vitamin D supplementation for the treatment or prevention of COVID-19, or the susceptibility to COVID-19 based on vitamin D status.
The evidence summary did not aim to define a level at which vitamin D status is deficient. Rather, it reiterated current UK Government advice and the findings of the 2016 Scientific Advisory Committee on Nutrition (SACN) report on vitamin D and health (2) that to protect musculoskeletal health, 25(OH)D levels should not fall below 25 nmol/L.
The scope of the NICE evidence summary also did not include studies on vitamin D for acute respiratory tract infections more generally, or the association of vitamin D status with immunity, hypertension or obesity, for example. However, a rapid review on vitamin D and acute respiratory tract infections (3), as well as a rapid scoping exercise on nutrition and immune function in relation to COVID-19 (4) was released by SACN at the same time as the NICE evidence summary was published.
While we coordinated with SACN on the release of the two reviews, they are ultimately separate. Should there be any changes to the UK government advice on vitamin D levels we will update our evidence summary accordingly.
Finally, the research included in this summary was selected following a thorough and precise literature search. Although no published randomised controlled trials on vitamin D and COVID-19 were found, 5 observational studies from peer-reviewed journals met the criteria for inclusion and were selected.
To clarify, NICE evidence summaries do not routinely include preprints (such as the Indonesian study mentioned), because they have not been through a minimum quality standard of peer-review prior to publishing.
However, both preprints and ongoing studies were listed in appendices to the evidence summary to alert readers to the wider, emerging evidence base. Our team is also continuing to monitor ongoing research on the subject should a review and update of the evidence summary become necessary.
1. National Institute for Health and Care Excellence. (2020). COVID-19 rapid evidence summary: vitamin D for COVID-19. Available at: https://www.nice.org.uk/advice/es28/chapter/Key-messages (Accessed: 6 July 2020).
2. The Scientific Advisory Committee on Nutrition. (2016). SACN vitamin D and health report. Available at: https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report (Accessed: 6 July 2020).
3. The Scientific Advisory Committee on Nutrition. (2020). Rapid review: Vitamin D and acute respiratory tract infections. Available at: https://www.gov.uk/government/groups/scientific-advisory-committee-on-nu... (Accessed: 6 July 2020).
4. The Scientific Advisory Committee on Nutrition. (2020). Rapid scoping exercise: Nutrition and immune function in relation to COVID-19. Available at: https://www.gov.uk/government/groups/scientific-advisory-committee-on-nu... (Accessed: 6 July 2020).
Competing interests: No competing interests