Vitamin D supplementation and testing in the UK: costly but ineffective?
BMJ 2021; 372 doi: https://doi.org/10.1136/bmj.n484 (Published 02 March 2021) Cite this as: BMJ 2021;372:n484
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Dear Editor
We read with interest the article by Bolland et al. (2021), Vitamin D supplementation and testing in the UK: costly but ineffective?
The Scientific Advisory Committee on Nutrition (SACN) welcomes the examination of the evidence on vitamin D and health and will consider whether any future assessment is required by the committee. However, we wish to note some inaccuracies in the paper in relation to SACN’s risk assessment of vitamin D and musculoskeletal outcomes (reference: SACN 2016).
It is incorrect to state that SACN did not assess the quality of the included evidence. This was undertaken using SACN’s framework for the evaluation of evidence, as stated in chapter 1 of the report. (reference: SACN framework)
It is incorrect to state that SACN’s recommendations are based on retracted or unreliable data. In particular, SACN’s conclusions on muscle strength and function were not reliant on studies undertaken by Pfeiffer et al (Pfeifer et al, 2009) and Sato et al (Sato et al, 2005a and Sato et al, 2005b) and the limitations of the Sato studies were noted in the report. Furthermore, the report highlights that the evidence on musculoskeletal health was mixed but overall suggested that risk of poor musculoskeletal health is increased at serum 25(OH)D <25 nmol/L.
It is important to recognise that the setting of a Reference Nutrient Intake (RNI) for the UK population was a precautionary approach to protect the most vulnerable groups in the population, to take account of variable exposure to sunshine and diet, and to ensure that 97.5% of the population maintained a serum 25(OH)D concentration ≥ 25 nmol/L throughout the year. The RNI of 10 micrograms per day therefore meets the needs of most adults and children age 1 year and over, including those at greater risk of deficiency because of little or no sunshine exposure (for example, because of being frail, housebound or wearing concealing clothing) or they have dark skin and may not synthesise enough vitamin D from sunlight (for example, people of African, African-Caribbean or south Asian family origin).
Population vitamin D intakes and status are monitored through the National Diet and Nutrition Survey. As noted in the SACN report, for all age groups in the UK, mean plasma 25(OH)D concentration is lowest in winter and highest in summer. Around 30-40% of the population have a plasma 25(OH)D concentration < 25 nmol/L in winter months (October to early March) compared to 2-13% in the summer. However, a large proportion of some population groups do not achieve a plasma/serum 25(OH)D concentration ≥ 25 nmol/L in summer (for example, around half of women of south Asian ethnic origin in southern England) (SACN, 2016).
Risk management, including economic evaluation or the assessment of policy options such as food fortification, is the responsibility of government and is outside SACN’s remit unless the committee has been specifically asked to advise on practical solutions. Economic evaluation is also outside SACN’s remit. (reference: code of practice).
Finally, Bolland et al (2021) highlight the widespread and costly testing of vitamin D status and prescribing of vitamin D supplements. While this is also outside SACN’s remit, we are aware that this practice is at odds with existing guidance from NICE, first published in 2014 (reference: NICE PH56).
Best wishes
Professor Ian Young (Chair, SACN) and Professor Julie Lovegrove (Deputy Chair, SACN) on behalf of SACN
References:
Bolland et al. Vitamin D supplementation and testing in the UK: costly but ineffective? (2021) BMJ 2021;372: n484 | doi: 10.1136/bmj.n484
Scientific Advisory Committee on Nutrition (SACN) (2016) Vitamin D and Health report Available here: SACN vitamin D and health report - GOV.UK (www.gov.uk)
SACN Framework for the Evaluation of Evidence (2012) ) Available here: Scientific Advisory Committee on Nutrition (SACN) - GOV.UK (www.gov.uk)
SACN Code of Practice (2020) Available here: Scientific Advisory Committee on Nutrition (SACN) - GOV.UK (www.gov.uk)
Pfeifer M, Begerow B, Minne HW, Suppan K, Fahrleitner-Pammer A & Dobnig H (2009) Effects of a long-term vitamin D and calcium supplementation on falls and parameters of muscle function in community-dwelling older individuals. Osteoporosis International. 20(2):315-322.
Sato Y, Iwamoto J, Kanoko T & Satoh K (2005a) Amelioration of osteoporosis and hypovitaminosis D by sunlight exposure in hospitalized, elderly women with Alzheimer's disease: a randomized controlled trial. Journal of Bone and Mineral Research. 20(8):1327-1333.
Sato Y, Iwamoto J, Kanoko T & Satoh K (2005b) Low-dose vitamin D prevents muscular atrophy and reduces falls and hip fractures in women after stroke: a randomized controlled trial. Cerebrovascular Diseases. 20(3):187-192.
Competing interests: No competing interests
Dear Editor
VitaminDforAll.org
Over 200 Scientists & Doctors Call For Increased Vitamin D Use To Combat COVID-19. VitaminDforAll.org [1]
On February 6 2021 there were 220 total signatories from 33 countries.
131 had medical degrees
116 had PhDs or equivalent or higher degrees
115 were professors
128 signatories took at least 4000 IU of Vitamin D per day
29 signatories took at least 10,000 IU of Vitamin D per day
Signatory Dr Steve Jones, a Fellow of the Royal Society and Emeritus Professor of Human Genetics, Department of Genetics, Evolution and Environment, University College London, UK, reports taking 4000 IU Vitamin D/day.
Throughout evolution Vitamin D and Vitamin C have protected us from viruses. However in the UK, a high incidence of vitamin D deficiency has been reported.[2] Although Vitamin D is safe and inexpensive, NICE guidelines recommend only 400 IU (10 micrograms) of vitamin D3, which is inadequate to combat the risk of severe Covid-19 infection.[3]
Microbiologist Dr Elizabeth Price writes that Vitamin D toxicity from supplements is rare and is associated with serum levels higher than 250 nmol/L.[4] Also that a daily dose of 4000 IU (100 micrograms) for three months will not result in levels anywhere near this figure which leaves a wide margin of safety.[5-7] She thinks that calcifediol should be used for treatment in the UK because it is more rapidly effective, better absorbed and 3.2 times more active than cholecalciferol which can take over a week to be fully active.[8] That may be too late for moderately or severely ill patients to respond to Vitamin D supplementation.[9]
I was also a signatory to Vitamin D for All. Cholecalciferol is one of the cheapest essential nutrient supplements but calcifediol, if available, would be better - even for a Scot like me!
1 VitaminDforAll: Over 200 Scientists and Doctors Call For Vitamin D To Combat COVID19
2 Sutherland JP, Zhou A, Leach MJ, Hyppönen E. Differences and determinants of vitamin D deficiency among UK biobank participants: A cross-ethnic and socioeconomic study. Clin Nutr. 2020 Nov 25;S0261-5614(20)30639-7 doi 10.1016/j.clnu.2020.11.019
3 NICE. Vitamin D for covid-19: evidence reviews for the use of vitamin D supplementation as prevention and treatment of covid-19. 2020. https://www.nice.org.uk/guidance/ng187/evidence/evidence-reviews-for-the...
4 Price EH. Vitamin D -- dose for prevention and the calcifediol derivative for treatment of COVID-19 | The BMJ
5 Jones G. Pharmacokinetics of vitamin D toxicity The American Journal of Clinical Nutrition, Volume 88, Issue 2, August 2008, Pages 582S–586S, https://doi.org/10.1093/ajcn/88.2.582S
6 Vieth R. Critique of the considerations for establishing the tolerable upper intake level for vitamin D: critical need for revision upwards. J Nutr 2006 Apr;136(4):1117-12. https://doi.org/10.1093/jn/136.4.1117
7 Vieth R, Chan PC, MacFarlane GD. Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level Am J Clin Nutr 2001 Feb;73(2):288-94. doi: 10.1093/ajcn/73.2.288)30639-7 doi: 10.1016/j.clnu.2020.11.019
8 J M Quesada-Gomez, R. Bouillon. Is calcifediol better than cholecalciferol for vitamin D supplementation? Osteoporosis International 2018; 29:1697–1711.
9 Entrenas Castillo M, Entrenas Costa LM, Vaquero Barrios JM, et al. Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study. J Steroid Biochem Mol Biol 2020;203:105751. doi: 10.1016/j.jsbmb.2020.105751. pmid: 32871238
Competing interests: No competing interests
Dear Editor
Bolland and colleagues summarise the issues around Vitamin D testing and supplementation very well.
At their 2018 annual conference Scottish GP representatives called on the Scottish Government (SG) to promote a 'Realistic Medicine' approach to Vitamin D testing and prescribing. The Chief Medical Officer (CMO) in Scotland gives clear advice on Vitamin D supplementation at https://www.gov.scot/publications/vitamin-d-advice-for-all-age-groups/.
The consensus among GPs was that we should follow the CMO advice and encourage the purchase of vitamin supplements by the majority of the population (estimated cost £5 per annum),
For those unable to afford this we called on SG to make Vitamin D available free of charge on the Minor ailments (now Pharmacy First) scheme. This has not happened.
Clinicians were asked to advise people follow CMO advice at consultations rather than perform Vitamin D tests and prescribe. GPs supported laboratories that insisted that there needed to be high clinical suspicion of osteomalacia or abnormal bone biochemistry before any vitamin D would be tested.
This has not led to a consistent approach and many doctors in Scotland continue to test vitamin D levels in February, find a deficiency and then advise lifelong vitamin D prescription via a GP.
All 4 devolved administrations need to take a lead on this issue and a adopt the low cost, mass self care approach with support provided to those who cannot self care. Testing should be reserved for the rare circumstance that someone is suspected of being vitamin D deficient despite taking routine supplementation as per CMO guidance.
The decision to not provide leadership on this issue for a further decade will see a further £1 billion of valuable public funds wasted for doubtful benefit.
Competing interests: No competing interests
Response to the chair and deputy chair of SACN
Dear Editor
We are surprised by the claims made by the chair and deputy chair of SACN that our article has inaccuracies/is incorrect about SACN’s 2016 report on vitamin D.
Firstly, we did not “state that SACN did not assess the quality of the included evidence.” Instead, we stated that SACN “did not provide any quality assessment of studies it reviewed.” There are 54 tables in Annex 2 of the report describing studies SACN considered during their evaluation, but none of them provide the measures of quality outlined in SACN’s Framework for the Evaluation of Evidence cited by the correspondents. If quality assessments were performed for individual studies and systematic reviews, that information was not conveyed to the reader, as would be standard practice in analysis of pooled evidence.
Secondly, we did not “state that SACN’s recommendations are based on retracted or unreliable data.” In fact, we highlighted that for the specific outcomes of muscle strength and function, the meta-analyses used to inform SACN’s judgements included studies that were later considered to be unreliable. Removal of these studies from those meta-analyses changes their findings, meaning that conclusions made by SACN based on these meta-analyses - that vitamin D improves muscle strength and function - are no longer valid.
The remainder of the response mainly elaborates upon SACN’s conclusions and roles and has little to do with our paper. We agree with the correspondents that the pattern of progressive increases in vitamin D supplementation and testing is at odds with the recommendations made by groups such as NICE, SACN, and its predecessor COMA. Those disparities raise important questions about both the value of the recommendations and their implementation.
We hope that SACN will revisit the broader issue of vitamin D deficiency and supplementation. As Dr Drummond Begg states in his rapid response to our article ‘the decision to not provide leadership on this issue for a further decade will see a further £1 billion of valuable public funds wasted for doubtful benefit’. The current practice around vitamin D is hugely expensive, but the relevant policies do not appear to protect the most vulnerable groups at highest risk of osteomalacia and rickets.
Competing interests: No competing interests