ArticlePDF Available

Abstract and Figures

Background Vitamin D is a micronutrient which is essential to help maintain bone and musculoskeletal health 1. However, recent research has highlighted a crucial supportive role for vitamin D in immune cell function, particularly in modulating the inflammatory response to viral infection 2,3. At a cellular level, vitamin D modulates both the adaptive and innate immune system through cytokines and regulation of cell signalling pathways 4. Vitamin D receptor (VDR) is present on both T and B immune cells; Vitamin D modulates the proliferation, inhibition and differentiation of these cells 5. In experimental models of lipopolysaccharide-induced inflammation, vitamin D is associated with lower concentrations of the pro-inflammatory cytokine Interleukin-6 (IL-6) 6 , which plays a significant role in Covid-19 induced acute respiratory distress syndrome (ARDS) 7. Vitamin D also reduces lipolysaccharide-induced lung injury in mice by blocking Abstract Background Recent research has indicated that vitamin D may have immune supporting properties through modulation of both the adaptive and innate immune system through cytokines and regulation of cell signalling pathways. We hypothesize that vitamin D status may influence the severity of responses to Covid-19 and that the prevalence of vitamin D deficiency in Europe will be closely aligned to Covid-19 mortality.
Content may be subject to copyright.
Issue: Ir Med J; Vol 113; No. 5; P81
Vitamin D and Inflammation: Potential Implications for Severity of Covid-19
E. Laird1, J. Rhodes2, R.A. Kenny1
1. The Irish Longitudinal Study on Ageing, School of Medicine, Trinity College Dublin, Ireland.
2. Institute of Translational Medicine, University of Liverpool.
Background
Vitamin D is a micronutrient which is essential to help maintain bone and musculoskeletal health1. However, recent
research has highlighted a crucial supportive role for vitamin D in immune cell function, particularly in modulating the
inflammatory response to viral infection2,3. At a cellular level, vitamin D modulates both the adaptive and innate
immune system through cytokines and regulation of cell signalling pathways4. Vitamin D receptor (VDR) is present on
both T and B immune cells; Vitamin D modulates the proliferation, inhibition and differentiation of these cells5. In
experimental models of lipopolysaccharide-induced inflammation, vitamin D is associated with lower concentrations
of the pro-inflammatory cytokine Interleukin- 6 (IL-6)6, which plays a significant role in Covid-19 induced acute
respiratory distress syndrome (ARDS)7. Vitamin D also reduces lipolysaccharide-induced lung injury in mice by blocking
Abstract
Background
Recent research has indicated that vitamin D may have immune supporting properties through modulation of both
the adaptive and innate immune system through cytokines and regulation of cell signalling pathways. We hypothesize
that vitamin D status may influence the severity of responses to Covid-19 and that the prevalence of vitamin D
deficiency in Europe will be closely aligned to Covid-19 mortality.
Methods
We conducted a literature search on PubMed (no language restriction) of vitamin D status (for older adults) in
countries/areas of Europe affected by Covid-19 infection. Countries were selected by severity of infection (high and
low) and were limited to national surveys or where not available, to geographic areas within the country affected by
infection. Covid-19 infection and mortality data was gathered from the World Health Organisation.
Results
Counter-intuitively, lower latitude and typically ‘sunny’ countries such as Spain and Italy (particularly Northern Italy),
had low mean concentrations of 25(OH)D and high rates of vitamin D deficiency. These countries have also been
experiencing the highest infection and death rates in Europe. The northern latitude countries (Norway, Finland,
Sweden) which receive less UVB sunlight than Southern Europe, actually had much higher mean 25(OH)D
concentrations, low levels of deficiency and for Norway and Finland, lower infection and death rates. The correlation
between 25(OH)D concentration and mortality rate reached conventional significance (P=0.046) by Spearman's Rank
Correlation.
Conclusions
Optimising vitamin D status to recommendations by national and international public health agencies will certainly
have benefits for bone health and potential benefits for Covid-19. There is a strong plausible biological hypothesis
and evolving epidemiological data supporting a role for vitamin D in Covid-19.
effects on the Ang-2-Tie-2 and renin-angiotensin pathways that are highly relevant to Severe Acute Respiratory
Syndrome Coronavirus2 (SARS-CoV-2) pathogenicity8. A ‘sufficient’ vitamin D serum level is linked to a switch from a
pro- to anti-inflammatory profiles in older adults9. This impact on the regulation of inflammation is of particular
importance in older adults, the obese and those with chronic conditions as they may already be pre-set for a higher
inflammatory response if exposed to Covid-19. A heightened immune response in people who are vitamin D deficient
may therefore increase the potential for ‘cytokine storm’ and consequent ARDS10.
In a recent large cross-sectional clinical trial (n = 18,883) lower vitamin D were associated with higher respiratory
infection rates and the effect was more pronounced in those with underlying lung conditions11. Case-control studies
have also reported associations between low vitamin D and increased risk of infection12 and supplementation with
vitamin D seems to help reduce both symptoms and antibiotic use13. Meta-analysis has also indicated a weak but
reduced risk of acute respiratory infection with vitamin D supplementation14 while a higher blood vitamin D status has
been associated with a small reduction in risk of pneumonia15. Thus, although vitamin D deficiency probably increases
risk of upper respiratory viral infections, the size of this effect is small. It is the impact of vitamin D deficiency on
cytokine response, and potentially therefore on lung injury, that is potentially much more important in the context of
Covid-19.
Common risk factors for vitamin D deficiency and Covid-19
Curiously, many of the risk factors for vitamin D deficiency (defined as a 25-hydroxyvitamin D (25(OH)D) <30nmol/L)
are also risk factors for Covid-19 infection/worse outcomes. For instance older age, obesity, being male and having
pre-existing chronic conditions are risk factors for deficiency16,17 all of which can also make individuals particularly
vulnerable to Covid-19 and complications from the virus18,19. Coincidentally, the mortality rate for Covid-19 is the
highest for those aged >80 years e.g. >20% in Italy and typically this is the age group with the highest levels of deficiency
regardless of country. Recent reports have indicated that those residing at higher latitudes, or with darker skin
pigmentation (Black Asian Minority ethnics BAME in UK) may be particularly affected by Covid-1920. BAME are also
at higher risk of obesity, pre-existing chronic disease (such as heart disease or diabetes) and vitamin D deficiency21,22.
Importantly, it is already evident that there is a world-wide association between northern latitude and increased Covid-
19 mortality23. Whilst there could be various explanations for this, it supports the hypothesis that sunlight exposure
and hence vitamin D status could be impacting on Covid-19 severity.
We hypothesize vitamin D plays a role in severity of responses to Covid-19 and the prevalence of vitamin D deficiency
in Europe will be closely aligned to Covid-19 mortality.
Methods
We conducted a literature search on PubMed (no language restriction) of vitamin D status (for older adults) in
countries/areas of Europe affected by Covid-19 infection. Countries were selected by severity of infection (high and
low) and were limited to national surveys or where not available, to geographic areas within the country affected by
infection (Italy, Spain, United Kingdom, France, Germany, Netherlands, Sweden, Ireland, Scotland, Portugal, Norway,
Finland (22-38). Papers were selected from 1999 onwards, when most measurements in older adults were available
in Europe. Covid-19 infection and mortality data was gathered from the World Health Organisation (for Scotland data
was sourced from Public Health England and the National Records Office Scotland)
Results are presented in Table 1 detailing for each country the total population (millions), the percentage aged >60
years and presence of vitamin D food fortification policy, vitamin D levels and Covid-19 mortality rates. As is the case
for vitamin D research, the majority of the studies used different methodologies for assessing vitamin D status and
many used different cut-points for deficiency status. Therefore, to standardise as much as possible we used the
commonly accepted thresholds of <25 nmol/L and <30 nmol/L as deficient status and low status is denoted as <50
nmol/L. Winter and summer values are also widely reported across papers and we have tried to average as much as
possible.
Results
Counter-intuitively, the lower latitude and typically ‘sunny’ countries such as Spain and Italy (particularly Northern
Italy), had low mean concentrations of 25(OH)D and high rates of vitamin D deficiency. These countries have also been
experiencing the highest infection and death rates in Europe. The northern latitude countries (Norway, Finland,
Sweden) which receive less UVB sunlight than Southern Europe, actually had much higher mean 25(OH)D
concentrations, low levels of deficiency and for Norway and Finland, lower infection and death rates. Across the mid-
latitudes of Europe, mean 25(OH)D is similar but with slight deviations. For instance, the mean level is slightly higher
in Ireland vs. Germany, UK or France and Ireland is also reporting lower rates of infection and deaths. Portugal appears
to be an outlier with a lower vitamin D status but also with lower rates of infection and mortality.
The calculated Covid-19 mortality rate (per million) from the selected countries was plotted against mean 25(OH)D
concentrations in Figure 1. The correlation between 25(OH)D concentration and mortality rate reached conventional
significance (P=0.046) by Spearman's Rank Correlation.
Table 1. Vitamin D status and Covid infection and mortality rates in UK and selected European countries1
1 Covid-19 infection and mortality data from the World Health Organisation (For Scotland data was sourced from Public Health
England and the National Records Office Scotland). The population percentage aged >65 years was from the World Bank data
resource. Due to the nature of vitamin D studies, 25(OH)D values have been measured by different methodologies and some have
been measured winter/summer though averages have been tried to be taken where possible. Covid-19 death rate calculated from
reported Covid deaths and country population
Figure 1. Calculated Covid-19 mortality rate and mean 25(OH)D concentration
P=0.046
Spain
Italy
France
Netherlands
UK
Sweden
Scotland
Ireland
Portugal
Germany
Norway
Finland
Discussion
In this short report we observed that low 25(OH)D concentrations appear to be associated with increased mortality
from Covid-19. Countries with a formal vitamin D fortification policy appear to have the lowest rates of infection whilst
countries with no policy and highest deficiency rates appear to be more adversely affected. This difference in Covid-
19 mortality by country has also been observed to form a North-South latitude gradient23. Observational reports have
also highlighted that Covid-19 infection and death rates appear to be higher in ethnic minority populations with darker
skin20 which research has shown to be at much higher risk of vitamin D deficiency21,22.
Given the strong plausible hypothesis and evolving clinical studies supporting role for vitamin D and immune function
for Covid-19, these observations are of concern. Optimising vitamin D status to public health recommendations could
enhance immune response but will be a significant challenge for both the UK and Europe. Dietary intakes of the vitamin
D are low across the continent / UK41 and few countries (apart from Sweden or Finland) have any formal mandatory
vitamin D food fortification policy. The Nordic countries also tend to have higher dietary intakes of vitamin D and their
higher vitamin D status reflects intakes from all sources and not just mandatory fortification. Ireland currently has a
‘voluntary vitamin D fortification policy’ and the higher 25(OH)D concentration compared with the UK or Scotland
could be reflective of this but again Ireland is much lower compared to the Nordic countries. However, introducing
mandatory fortification of products (such as dairy) with vitamin D (as practiced in some Nordic countries) and
promoting an increased dietary intake of vitamin D rich foods is considered safe and has the potential to help virtually
eliminate deficiency in the population33,42. This new policy would require formal Government approval and careful
modelling of the current level of vitamin D intake taking into account voluntary fortification and self-supplementation.
However, it could have significant benefits in terms of bone and musculoskeletal health (economically and socially)43-
45 in addition to the suggested immune health benefits. Moreover this is particularly timely given current lock-down
arrangements and government advice e.g. in UK to avoid sunbathing. In the interim strong public awareness campaigns
regarding vitamin D sources and supplementation are recommended.
Official vitamin D intake policy
Recommendations for vitamin D intakes for older adults by various public health agencies (the Institute of Medicine
(IOM) report (North American Health authority)1, the Scientific Advisory Committee on Nutrition (SACN) (United
Kingdom) report46, the Nordic Nutritional Recommendations (NNR) report (Nordic countries)47 and the European Food
Safety Authority (EFSA) report)48 are displayed in Table 2. For those with little sun exposure (housebound or confined)
the recommended daily intake is 10 -20 ug (400-800 International units per day). Due to inadequate intake in the diet
and lack of mandatory fortification in Europe and the United Kingdom (and confinement - lack of sunlight), a vitamin
D supplement maybe required to achieve these recommendations. Currently there is insufficient evidence that
suggests that higher intakes of vitamin D are required for extra-skeletal health. The optimum doses for Covid-19
protection are not known.
Table 2. Public health authority vitamin D intake recommendations
Report
25(OH)D cut-off
for deficiency
Optimal
25(OH)D
Recommended intake
for older adults with
little or no sunlight
exposure
Institute of Medicine (IOM)
2011 report1
<30 nmol/L
>50 nmol/L
20 μg daily
Scientific Advisory
Committee on Nutrition
(SACN) 2016 report46
<25 nmol/L
Not stated
10 μg daily
Nordic Nutritional
Recommendations (NNR)
2012 report47
<25 nmol/L
>50 mmol/L
15 μg to 20 μg daily
EFSA 2016 report48
not stated
>50 nmol/L
15 μg daily
Limitations
Interpretation of observational and cross-sectional data on vitamin D is hampered by the lack of formal set cut-off
points which denote deficiency across different countries and the method of vitamin D measurement which can over
or underestimate concentrations. Therefore some caution must be used in the interpretation of any analysis although
this is typical in vitamin D cross-country comparisons and we have adhered to deficiency cut-points applied in similar
analyses. Furthermore, there are also many more micronutrients which have been observed to have
immunomodulation effects (such as zinc, selenium, vitamin B6 etc.) which may also have a role in immune function in
Covid-19 infections which we did not examine as it was not the focus of this particular analysis. Moreover, the data on
Covid-19 infection rates country by country are difficult to interpret because of variation in testing. Finally, this work
is observational and maybe be confounded by a number of factors including the varied rate of infection in different
countries, different approaches to screening which alters prevalence rates, differences in demographics ie ageing
cohorts, and given the speed of the outbreak and infection, it is likely that other unknown factors will exist.
Conclusions
The circumstantial and experimental evidence suggests that vitamin D may have an important supportive role for the
immune system, particularly in regulating cytokine response to pathogens. Vitamin D levels are low in countries in
Europe which have high infection and mortality rates. Optimising vitamin D status to recommendations by national
and international public health agencies will certainly have benefits for bone health and potential benefits for Covid-
19. There is a strong plausible biological hypothesis and evolving epidemiological data supporting a role for vitamin D
in Covid-19. Ideally, results from randomized controlled trials are required to fully investigate the association.
However, these would have to be community-based, which would be impractical during lock-down, and there would
also likely be difficulty in persuading participants to risk taking a placebo vitamin. Observational studies correlating
vitamin D at time of hospital admission with subsequent outcome would be extremely valuable and should be urgently
pursued. In the meantime we recommend that more publicity be given to current guidelines for vitamin D dietary
intake and supplementation as denoted by the public health agencies in the USA, UK and Europe.
Declaration of Conflicts of Interest:
The authors have nothing to declare.
Corresponding Author:
Professor Rose Anne Kenny
Department of Medical Gerontology,
6th floor, Mercers Institute for Ageing,
St James Hospital,
Dublin 8,
Ireland.
Email: rkenny@tcd.ie
References:
1. Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, Institute of Medicine. Dietary
Reference Intakes for Calcium and Vitamin D. Washington, DC: The National Academies Press; 2011.
2. Vanherwegen AS, Gysemans C, Mathieu. Regulation of immune function by vitamin D and its use in diseases of
immunity. Endocrinol Metab Clin. 2017 Dec 1;46:1061-1094.
3. Beard JA, Bearden A, Striker R (2011) Vitamin D and the antiviral state. J Clin Virol. 2011 Mar 1;50:194-200
4. Di Rosa M, Malaguarnera M, Nicoletti F, Malaguarnera L. Vitamin D3: a helpful immuno-modulator. Immunology.
2011 Oct 1;134:123-139.
5. Wu D, Lewis ED, Pae M, Meydani SN. Nutritional modulation of immune function: analysis of evidence,
mechanisms, and clinical relevance. Frontiers in immunology. 2019 Jan 15;9:3160.
6. Zhang Y, Leung DY, Richers BN, Liu Y, Remigio LK, Riches DW, Goleva E. Vitamin D inhibits monocyte/macrophage
proinflammatory cytokine production by targeting MAPK phosphatase-1. J Immunol. 2012 Mar 1;88:2127-2135.
7. McGonagle D, Sharif K, O’Regan A, Bridgewood C. The Role of Cytokines including Interleukin-6 in COVID-19
induced Pneumonia and Macrophage Activation Syndrome-Like Disease. Autoimmunity Reviews (In Press) April
2020.
8. Kong J, Zhu X, Shi Y, Liu T, Chen Y, Bhan I, Zhao Q, Thadhani R, Li YC.
Mol Endocrinol. 2013 Dec;2712:2116-25.
9. Laird E, McNulty H, Ward M, Hoey L, McSorley E, Wallace JM, Carson E, Molloy AM, Healy M, Casey MC,
Cunningham C. Vitamin D deficiency is associated with inflammation in older Irish adults. J Clin Endocrinol &
Metab. 2014 May 1;99:1807-1815.
10. Xu Z, Shi L, Wang Y, Zhang J, Huang L, Zhang C, Liu S, Zhao P, Liu H, Zhu L, Tai Y. Pathological findings of COVID-19
associated with acute respiratory distress syndrome. Lancet Respir Med. 2020 Apr 1;8(4):420-422.
11. Ginde AA, Mansbach JM, Camargo CA. Association between serum 25-hydroxyvitamin D level and upper
respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009
Feb 23;169:384-390.
12. Jolliffe DA, Griffiths CJ, Martineau AR. Vitamin D in the prevention of acute respiratory infection: Systematic review
of clinical studies. J Steroid Biochem Mol Biol. 2013 Jul 1;136:321-329.
13. Bergman P, Norlin AC, Hansen S, Rekha RS, Agerberth B, Björkhem-Bergman L, Ekström L, Lindh JD, Andersson J.
Vitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind
intervention study. BMJ open. 2012 Jan 1;2:e001663.
14. Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, Dubnov-Raz G, Esposito S, Ganmaa D,
Ginde AA, Goodall EC. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review
and meta-analysis of individual participant data. BMJ. 2017;356:i6583.
15. Zhou YF, Luo BA, Qin LL. The association between vitamin D deficiency and community-acquired pneumonia: A
meta-analysis of observational studies. Medicine (Baltimore). 2019 Sep 1;98:e17252.
16. Laird E, Kenny RA. Vitamin D deficiency in Ireland: Implications for COVID-19. Results from the Irish Longitudinal
Study on Ageing. April 4 2020. https://www.doi.org/10.38018/TildaRe.2020-05.
17. Pearce SH, Cheetham TD. Diagnosis and management of vitamin D deficiency. BMJ. 2010 Jan 11;340:b5664.
18. Jia X, Yin C, Lu S, Chen Y, Liu Q, Bai J, Lu Y. Two Things about COVID-19 Might Need Attention. Preprints. 2020,
2020020315 (doi 10.20944/preprints202002.0315.v1)
19. Thornton J. Don’t forget chronic lung and immune conditions during covid-19, says WHO. BMJ. 2020;368:m1192
20. ICNARC report on COVID-19 in critical care. Accessed 07/04/2020. https://www.icnarc.org/About/Latest-
News/2020/04/04/Report-On-2249-Patients-Critically-Ill-With-Covid-19
21. Laird E, O'Malley D, Crowley VE, Healy M. A high prevalence of vitamin D deficiency observed in the Dublin South
East Asian population. Proceedings of the Nutrition Society. 2018;77(OCE3).
22. Farrar MD, Kift R, Felton SJ, Berry JL, Durkin MT, Allan D, Vail A, Webb AR, Rhodes LE. Recommended summer
sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin. Am J Clin
Nutr. 2011 Nov 1;94:1219-1224.
23. Braiman Mark. Latitude Dependence of the COVID-19 Mortality Rate-A Possible Relationship to Vitamin D
Deficiency? SSRN. Mar 26; 3561958.
24. Pini G, Troiano L, Vescovini R, Sansoni P, Passeri M, Gueresi P, Delsignore R, Pedrazzoni M, Franceschi C (2003)
Low vitamin D status, high bone turnover, and bone fractures in centenarians. J Clin Endocrinol Metab Nov
1;88:5109-5115.
25. Shardell M, Hicks GE, Miller RR, Kritchevsky S, Andersen D, Bandinelli S, Cherubini A, Ferrucci L (2009) Association
of low vitamin D levels with the frailty syndrome in men and women. J Gerontol A Biol Sci Med Sci Jan 1; 64:69-
75.
26. Bettica P, Bevilacqua M, Vago T, Norbiato G. High prevalence of hypovitaminosis D among free-living
postmenopausal women referred to an osteoporosis outpatient clinic in northern Italy for initial screening.
Osteoporos Int. 1999 Mar 1; 9:226-229.
27. Isaia G, Giorgino R, Rini GB, Bevilacqua M, Maugeri D, Adami S. Prevalence of hypovitaminosis D in elderly women
in Italy: clinical consequences and risk factors. Osteoporos Int. 2003 Jul 1;14:577-582.
28. Aguado P, Del Campo MT, Garces MV, Gonzalez-Casaus ML, Bernad M, Gijon-Banos J, Mola EM, Torrijos A,
Martinez ME. Low vitamin D levels in outpatient postmenopausal women from a rheumatology clinic in Madrid,
Spain: their relationship with bone mineral density. Osteoporos Int. Sep1;11:739-744.
29. Almirall J, Vaqueiro M, Baré ML, Anton E. Association of low serum 25-hydroxyvitamin D levels and high arterial
blood pressure in the elderly. Nephrol Dial Transplant. 2010 Feb 1;25:503-509.
30. Olmos JM, Hernández JL, García-Velasco P, Martínez J, Llorca J, González-Macías J. Serum 25-hydroxyvitamin D,
parathyroid hormone, calcium intake, and bone mineral density in Spanish adults. Osteoporos Int. 2016 Jan
1;27:105-113.
31. Ramnemark A, Norberg M, Pettersson-Kymmer U, Eliasson M. Adequate vitamin D levels in a Swedish population
living above latitude 63 N: the 2009 Northern Sweden MONICA study. Int J Circumpolar Health. 2015 Jan
31;74:27963.
32. Petrenya N, Lamberg-Allardt C, Melhus M, Broderstad AR, Brustad M. Vitamin D status in a multi-ethnic population
of northern Norway: the SAMINOR 2 clinical survey. Public Health Nutr. 2019 Feb 15;15:1-5.
33. Jääskeläinen T, Itkonen ST, Lundqvist A, Erkkola M, Koskela T, Lakkala K, Dowling KG, Hull GL, Kröger H, Karppinen
J, Kyllönen E. The positive impact of general vitamin D food fortification policy on vitamin D status in a
representative adult Finnish population: evidence from an 11-y follow-up based on standardized 25
hydroxyvitamin D data. Am J Clin Nutr 2017 Jun1;105:1512-1520.
34. Aspell N, Laird E, Healy M, Shannon T, Lawlor B, O’Sullivan M. The prevalence and determinants of vitamin D status
in community-dwelling older adults: results from the English Longitudinal Study of Ageing (ELSA). Nutrients. 2019
Jun 1;11:1253.
35. Laird E, O’Halloran AM, Carey D, Healy M, O’Connor D, Moore P, Shannon T, Molloy AM, Kenny RA. The prevalence
of vitamin D deficiency and the determinants of 25 (OH) D concentration in older Irish adults: Data from The Irish
Longitudinal Study on Ageing (TILDA). J Gerontol A Biol Sci Med Sci. 2018 Mar 14;73:519-525.
36. Macdonald HM, Mavroeidi A, Fraser WD, Darling AL, Black AJ, Aucott L, O’Neill F, Hart K, Berry JL, Lanham-New
SA, Reid DM. Sunlight and dietary contributions to the seasonal vitamin D status of cohorts of healthy
postmenopausal women living at northerly latitudes: a major cause for concern? Osteoporos Int. 2011 Sep
1;22:2461-2472.
37. Rabenberg M, Scheidt-Nave C, Busch MA, Rieckmann N, Hintzpeter B, Mensink GB. Vitamin D status among adults
in Germanyresults from the German Health Interview and Examination Survey for Adults (DEGS1). BMC Public
health. 2015 Dec 1;15:641.
38. Cougnard-Grégoire A, Merle BM, Korobelnik JF, Rougier MB, Delyfer MN, Féart C, Le Goff M, Dartigues JF,
Barberger-Gateau P, Delcourt C. Vitamin D deficiency in community-dwelling elderly is not associated with age-
related macular degeneration. J Nutr. 2015 Aug 1;145:1865-1872.
39. Santos A, Amaral TF, Guerra RS, Sousa AS, Álvares L, Moreira P, Padrão P, Afonso C, Borges N. Vitamin D status
and associated factors among Portuguese older adults: results from the Nutrition UP 65 cross-sectional study. BMJ
open. 2017 Jun1; 7(6).
40. Snijder MB, van Dam RM, Visser M, Deeg DJ, Dekker JM, Bouter LM, Seidell JC, Lips P. Adiposity in relation to
vitamin D status and parathyroid hormone levels: a population-based study in older men and women. J Clin
Endocrinol Metab. 2005 Jul 1; 90:4119-4123.
41. Lips P, Cashman KD, Lamberg-Allardt C, Bischoff-Ferrari HA, Obermayer-Pietsch B, Bianchi ML, Stepan J, Fuleihan
GE, Bouillon R. Current vitamin D status in European and Middle East countries and strategies to prevent vitamin
D deficiency: a position statement of the European Calcified Tissue Society. Eur J Endocrinol. 2019 Apr 1 180:P23-
54.
42. Itkonen ST, Andersen R, Björk AK, Brugård Konde Å, Eneroth H, Erkkola M, Holvik K, Madar AA, Meyer HE, Tetens
I, Torfadóttir JE. Vitamin D status and current policies to achieve adequate vitamin D intake in the Nordic countries.
Scand J Public Health. 2020 Jan 9:1403494819896878.
43. Aguiar M, Andronis L, Pallan M, Högler W, Frew E. The economic case for prevention of population vitamin D
deficiency: a modelling study using data from England and Wales. EJCN 2019 Aug 20:1-9.
44. Sandmann A, Amling M, Barvencik F, König HH, Bleibler F. Economic evaluation of vitamin D and calcium food
fortification for fracture prevention in Germany. Public health nutrition. 2017 Jul 1;20:1874-1883.
45. Hiligsmann M, Reginster JY. The projected public health and economic impact of vitamin D fortified dairy products
for fracture prevention in France. Expert review of pharmacoeconomics & outcomes research. 2018 Mar 4;18:191-
195.
46. Scientific Advisory Committee on Nutrition. Vitamin D and Health. 2016;2016.
47. Secretary of the Nordic Council of Ministers, Nordic Council of Ministers. Nordic Nutrition Rcommendations:
Integrating nutrition and physical activity. 2014.
48. EFSA Panel on Dietetic Products NaAN. Dietary reference values for vitamin D. 2016.
... [83,84] The epidemiological data reveals importance of vitamin D to reduce infection rate, severity and complications and may play a potential role during COVID-19 due to anti-inflammatory responses. [85] This impact of retardation of inflammation is particularly important in immuno-compromised individuals as they suffer from hyper-inflammatory responses after COVID-19. In people with deficiency of vitamin D, immune response may not regulate properly and hence produce more cytokines and consequently acute respiratory distress syndrome. ...
... [97] It is also noteworthy that individuals with darker skin pigmentation or those who reside at high latitudes are particularly infected with COVID-19. These populations also have high risk of preexisting chronic disease, obesity and deficiency of vitamin D. [85,98] The severity of disease in these individuals is due to inadequate sun exposure and hence, deficiency of vitamin D. ...
Article
Full-text available
The possible use of dietary components as therapeutic agents is well known and could be a tool against Coronavirus Disease 2019 (COVID-19). This review summarizes the evidence-based literature for immuno-modulation and antiviral activity of different vitamins (A, B, C, D, E), omega-3 fatty acids, selenium, zinc and flavonoids. These substances lessen the vulnerability of risk groups and retard intricate chain of events related to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) invasion. The potential roles of these substances include inhibition of SARS-CoV-2 pathogenesis, inactivation of ACE2 receptors, regulation of innate and adaptive immunity, stimulation of anti-inflammatory responses, regulation of cytotoxic cells activity, antiviral immune induction, retardation of incessant viral replications, suppression of cell signaling pathways and putative inhibition of SARS-CoV-2 major proteases. Moreover, after recovery from COVID-19, nourishing diet is needed to speed up the long-haul symptoms and lingering health issues. ARTICLE HISTORY
... [83,84] The epidemiological data reveals importance of vitamin D to reduce infection rate, severity and complications and may play a potential role during COVID-19 due to anti-inflammatory responses. [85] This impact of retardation of inflammation is particularly important in immuno-compromised individuals as they suffer from hyper-inflammatory responses after COVID-19. In people with deficiency of vitamin D, immune response may not regulate properly and hence produce more cytokines and consequently acute respiratory distress syndrome. ...
... [97] It is also noteworthy that individuals with darker skin pigmentation or those who reside at high latitudes are particularly infected with COVID-19. These populations also have high risk of preexisting chronic disease, obesity and deficiency of vitamin D. [85,98] The severity of disease in these individuals is due to inadequate sun exposure and hence, deficiency of vitamin D. ...
Article
Full-text available
The possible use of dietary components as therapeutic agents is well known and could be a tool against Coronavirus Disease 2019 (COVID-19). This review summarizes the evidence-based literature for immuno-modulation and antiviral activity of different vitamins (A, B, C, D, E), omega-3 fatty acids, selenium, zinc and flavonoids. These substances lessen the vulnerability of risk groups and retard intricate chain of events related to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) invasion. The potential roles of these substances include inhibition of SARS-CoV-2 pathogenesis, inactivation of ACE2 receptors, regulation of innate and adaptive immunity, stimulation of anti-inflammatory responses, regulation of cytotoxic cells activity, antiviral immune induction, retardation of incessant viral replications, suppression of cell signaling pathways and putative inhibition of SARS-CoV-2 major proteases. Moreover, after recovery from COVID-19, nourishing diet is needed to speed up the long-haul symptoms and lingering health issues.
... Of note, the severely ill COVID-19 patients also had significantly higher IL-6 levels as compared to those seen in asymptomatic patients [116•]. Contrary to expectation, in a study that observed the prevalence of high and low COVID-19 cases and vitamin D status across several European countries, sunny countries were reported to having lower vitamin D levels, higher vitamin D deficiency, and the higher rates of infections than countries that received less UVB sunlight [109]. However, association studies are incapable of demonstrating causation. ...
Article
Full-text available
Purpose of Review Although COVID-19 was originally characterized as a respiratory disease, recent findings have shown lingering side effects in those who have recovered, and much is still unknown about the long-term consequences of the illness. Thus, the potential of unearthing multi-system dysfunction is high, with current data revealing significant impacts on musculoskeletal health. Recent Findings Multiple animal models of COVID-19 infection have revealed significant post-infection bone loss at several different skeletal sites. While how this loss occurred is unknown, this current review discusses the primary bone loss studies, and examines the possible mechanisms of action including: direct infection of bone marrow macrophages or hematopoietic progenitors, a proinflammatory response as a result of the COVID-19 induced cytokine storm, and/or a result of hypoxia and oxidative stress. This review will further examine how therapeutics used to treat COVID-19 affect the skeletal system. Finally, this review will examine the possible consequence that delayed care and limited healthcare accessibility has on musculoskeletal-related patient outcomes. Summary It is important to investigate the potential impact COVID-19 infection has on musculoskeletal health.
... D dans la population générale, soit en raison d'une faible exposition au soleil ou d'une alimentation pauvre en graisses. Les jeunes enfants, les personnes âgées et les personnes obèses sont les groupes de populations les plus susceptibles de connaître cette hypovitaminose [20]. Par ailleurs, de multiples maladies liées à l'immunité sont corrélées à de faibles niveaux sériques de Vit. ...
Article
Introduction. From the onset of the COVID-19 pandemic, calls for taking certain dietary supplements were launched to prevent or treat this disease. Given the novelty of the subject, there are few national or international data on their consumption by the general public. Objective. To explore changes in dietary supplement consumption before and during this pandemic. Population and methods. A cross-sectional study was carried out online using a questionnaire, among 1000 Algerian citizens. Results. The prevalence of dietary supplement consumption doubled during this crisis (29.4% before vs 63.4% after the pandemic). Overall, a significant increase was noted in vitamins minerals, trace elements, and plant supplements intake, and was respectively 24.7%, 18.4% and 9.2% before vs 58.0%, 50.0% and 26.0% during the pandemic. The major changes concerned supplements based on vitamins (Vit.) C and D, zinc, magnesium, selenium, cloves, ginger, turmeric, liquorice, and omega-3. Conclusion. Although the scientific debate about the health impact of dietary supplements is endless, their consumption continues to increase. The biggest challenge now is to standardize their indications.
... D dans la population générale, soit en raison d'une faible exposition au soleil ou d'une alimentation pauvre en graisses. Les jeunes enfants, les personnes âgées et les personnes obèses sont les groupes de populations les plus susceptibles de connaître cette hypovitaminose [20]. Par ailleurs, de multiples maladies liées à l'immunité sont corrélées à de faibles niveaux sériques de Vit. ...
Article
Full-text available
Introduction. Dès l’apparition de la pandémie de COVID-19, des appels à la prise de certains compléments alimentaires ont été lancés pour prévenir ou traiter cette maladie. Vu la nouveauté du sujet, il existe peu de données nationales ou internationales sur leur consommation par le grand public. Objectif. Explorer les changements dans la consommation des compléments alimentaires avant et pendant cette pandémie. Population et méthodes. Une étude transversale a été réalisée en ligne par le biais d’un questionnaire, auprès de 1000 citoyens algériens. Résultats. La prévalence de prise des compléments alimentaires a doublé pendant cette crise (29,4% avant vs 63,4% durant la pandémie). Globalement, une hausse significative de la prise des suppléments á base de vitamines (Vit.), de minéraux et oligo-éléments et de plantes a été notée et était respectivement de 24,7%, 18,4% et 9,2% avant vs 58,0%, 50,0% et 26,0% durant la pandémie. Les changements majeurs concernaient les suppléments à base de Vit. C et D, zinc, magnésium, sélénium, clou de girofle, gingembre, curcuma, réglisse et oméga 3. Conclusion. Bien que le débat scientifique autour de l’impact sanitaire des compléments alimentaires n’en finisse pas, leur consommation continue sa progression. Le plus grand défi maintenant est de standardiser leurs indications.
... Its involvement goes beyond bone metabolism to act at different levels of human physiology: preventing cancers (3), cardiovascular protection (4), regulation of the immune system (5). In many recent studies, vitamin D status has been also correlated with the severity of Corona Virus Disease 2019 (6,7). ...
Article
Full-text available
Background: Vitamin D deficiency is one of the most common medical conditions worldwide. In Tunisia, several studies evaluated Vitamin D status, but this was concerning specific populations (pregnant women, obese or diabetic patients and children with asthma). The only study that evaluated Vitamin D status in a healthy Tunisian population was conducted by Meddeb and al. in 2002. The update of data available, based on the currently recommended limits, is necessary. This study aimed to estimate the prevalence of hypovitaminosis D in a healthy Tunisian population, and correlate the values with potential risk factors. Methods: It was conducted on 209 Tunisian healthy subjects. Data collected included clinical characteristics and dietary intakes. We measured 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), glycemia, creatinine, calcium, phosphorus, and alkaline phosphatase concentrations. Hypovitaminosis D was retained for 25(OH)D concentrations <75 nmol/L. Vitamin D deficiency was defined by 25(OH)D concentrations <25 nmol/L. Results: The prevalence of hypovitaminosis D and vitamin D deficiency were respectively 92.3% and 47.6%. The main factors that were significantly associated with low vitamin D
... There are suggested biological mechanisms indicating that vitamin D could contribute to reduction of COVID-19 severity among infected patients [14]. An ecological study from Europe showed that countries with lower mean serum 5-hydroxyvitamin D [25(OH) D] concentration had higher odds of mortality from COVID-19 [15]. According to a recent systematic review published on The Lancet Global Health, vitamin D deficiency is common, affecting large segment of population in Africa [16]. ...
Article
Full-text available
Introduction: there is a large body of literature that has linked vitamin D status in the population with COVID-19 infection risk and disease severity. However, there is paucity of evidence in African context. Hence, this study aimed to conduct an ecological analysis to explore correlation between population level vitamin D status, COVID-19 infection, and mortality in Africa. Methods: an ecological study was conducted using data from different open sources, published literatures and organizational databases. In the final analysis, we included 23 African countries which had data on prevalence of vitamin D deficiency, population level mean serum 25 (OH) D concentrations and COVID-19 data. We employed spearman correlation and linear regression. All tests were two-sided, and P- value <0.05 was considered statistically significant. Results: based on our analysis, the prevalence of vitamin D deficiency is positively correlated (r=0.6265; p= 0.0094) while mean 25(OH) D concentration is negatively correlated (r=-0.4941; p= 0.0194) with COVID-19 mortality. In addition, the median age of the national population (r=0.7015; p= 0.0003), prevalence of current use of tobacco (r=0.6071; p= 0.0075) and prevalence of obesity among adult population (r=0.7143; p= 0.0003) were positively correlated with both COVID-19 infection and mortality in Africa. Nonetheless, vitamin D status was not positively correlated with observed case fatality rate and COVID-19 infection rate. Conclusion: population vitamin D status might be related to COVID-19 mortality but not with infection rate in Africa. Due to the increasing weight of evidence that shows a link between COVID-19 and vitamin D, we strongly recommend well-designed controlled studies to explore causality and clinical trials to find out the effect of vitamin-D supplementation in the treatment and prevention of COVID-19 in African settings.
Coronavirus 2019 (COVID-19) is an infectious disease that has brought life to a standstill around the world. Until a vaccine was found to combat COVID-19, the world conducted research and made recommendations for nutritional natural foods. Considering the risks incurred by contracting the disease, even though the production of various vaccines and vaccination of healthy people has started in some countries, individuals need useful foods to be ready for the COVID-19 pandemic. Recently, nutrient contents such as antioxidant compounds, vitamins, minerals, and probiotics that contribute to the immune system have been investigated. This paper attempts to determine the role of these dietary supplements in reducing the risk of COVID-19 and/or changing the course of the disease in COVID-19 patients and their effects on mortality. Supplements used and recommended for the COVID-19 pandemic life were investigated. In conclusion, more research is needed to determine the effectiveness of nutrients, vitamins, minerals, probiotics, prebiotics, and antioxidants used during the COVID-19 pandemic to inhibit the effect of SARS-CoV-2. In order to overcome the new global crisis, nutritional cures and treatments should be upgraded. However, additional research on the subject is needed.
Article
Purpose: To correlate in COVID-19 pneumonia CT-based semi-quantitative score of pulmonary involvement with high serum levels of KL-6, a biomarker of disease severity. Methods: Between March 28 to May 21, 2020, 196 patients with strong suspicion of SARS-CoV-2 were evaluated with RT-PCR for SARS-CoV-2, chest CT scan and blood test, including KL-6 serum protein, in our Emergency Unit. The final population included only patients who underwent blood sampling for KL-6 within 5 days from CT scan (n = 63), including n = 37 COVID-19-positive patients and n = 26 with negative RT-PCR testing for SARS-CoV-2 (control group). A semi-quantitative CT score was calculated based on the extent of lobar involvement (0:0%; 1, < 5%; 2:5-25%; 3:26-50%; 4:51-75%; 5, > 75%; range 0-5; global score 0-25). Results: CT score was significantly correlated with serum value of KL-6 (r = 27, p = 0.035). This correlation was also present in COVID-19 positive patients (r = 0.423, p = 0.009) and CT score median value was significantly higher in patients with high KL-6 value (> 400 U/mL; 12.00, IQR 5.00-18.00, p-value 0.027). In control group, no statistically significant correlation was found between CT score and KL-6 value and CT score was higher in patients with high KL-6, although this difference was not statistically significant (5.00, IQR:1.75-8.00 versus 3.50, IQR:2.00-6.50). "Crazy paving" at the right upper (n = 8; 61.5%) and middle lobe (n = 4; 30.8%) and "consolidation" at the middle lobe (n=5; 38.5%) were observed in COVID-19 group with a significant difference between patients with high KL-6 value. Conclusion: CT score is highly correlated with KL-6 value in COVID-19 patients and might be beneficial to speed-up diagnostic workflow in symptomatic cases.
Article
Full-text available
Since the beginning of the SARS-CoV-2 pandemic, there has been much discussion about the role of diet and antiviral immunity in the context of SARS-CoV-2 infection. Intake levels of vitamins D, C, B12, and iron have been demonstrated to be correlated with lower COVID-19 incidence and mortality. Obesity has been demonstrated to be an independent risk for the severity of COVID-19 infection in adults and also in children. This may be due to different mechanisms, mainly including the gut dysbiosis status observed in obese children. Moreover, the existence of a gut–lung axis added new knowledge to on the potential mechanisms by which diet and dietary substances may affect immune function. The aim of this narrative review is to address the intricate inter-relationship between COVID-19, immune function, and obesity-related inflammation and to describe the role of nutrients and dietary patterns in enhancing the immune system. Two ways to fight against COVID-19 disease exist: one with an antiviral response through immune system boosting and another with antioxidants with an anti-inflammatory effect. In the current pandemic situation, the intake of a varied and balanced diet, rich in micronutrients and bioactive compounds including fibers, should be recommended. However, clinical studies conducted on children affected by SARS-CoV-2 infection and comorbidity are warranted.
Article
Full-text available
Emerging evidence has shown that vitamin D deficiency may be related with community-acquired pneumonia (CAP), but individually published studies showed inconclusive results. The aim of this study was to quantitatively summarize the association between vitamin D and the CAP.We conducted this meta-analysis though a systematic literature search of PubMed, Medline, and EMBASE up to 31 September 2018 with the following keywords 'vitamin D' or 'cholecalciferol' or '25-hydroxyvitamin D' or '25(OH)D' in combination with 'community-acquired pneumonia' or 'CAP' or 'pneumonia' with no limitations. This meta-analysis was performed following the guidelines of Meta-analysis of Observational Studies in Epidemiology. The association between vitamin D levels and CAP were measured as odds ratio (OR) and weighted mean difference (WMD). Results were combined using a random-effect or a fix-effect meta-analysis, and sensitivity analyses were conducted to explore potential factors.Eight observational studies involving 20,966 subjects were included. In this meta-analysis, CAP patients with vitamin D deficiency (serum 25(OH)D levels <20 ng/mL) experienced a significantly increased risk of CAP (odds ratio (OR) = 1.64, 95% confidence intervals (CI): 1.00, 2.67), and an obvious decrease of -5.63 ng/mL (95% CI: -9.11, -2.14) in serum vitamin D was demonstrated in CAP patients. Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect.The evidence from this meta-analysis indicates an association between vitamin D deficiency and an increased risk of CAP patients. However, well-designed trails are required to determine the explicit effect of vitamin D supplementation.
Article
Full-text available
Background: Vitamin D deficiency (VDD) affects the health and wellbeing of millions worldwide. In high latitude countries such as the United Kingdom (UK), severe complications disproportionally affect ethnic minority groups. Objective: To develop a decision-analytic model to estimate the cost effectiveness of population strategies to prevent VDD. Methods: An individual-level simulation model was used to compare: (I) wheat flour fortification; (II) supplementation of at-risk groups; and (III) combined flour fortification and supplementation; with (IV) a 'no additional intervention' scenario, reflecting the current Vitamin D policy in the UK. We simulated the whole population over 90 years. Data from national nutrition surveys were used to estimate the risk of deficiency under the alternative scenarios. Costs incurred by the health care sector, the government, local authorities, and the general public were considered. Results were expressed as total cost and effect of each strategy, and as the cost per 'prevented case of VDD' and the 'cost per Quality Adjusted Life Year (QALY)'. Results: Wheat flour fortification was cost saving as its costs were more than offset by the cost savings from preventing VDD. The combination of supplementation and fortification was cost effective (£9.5 per QALY gained). The model estimated that wheat flour fortification alone would result in 25% fewer cases of VDD, while the combined strategy would reduce the number of cases by a further 8%. Conclusion: There is a strong economic case for fortifying wheat flour with Vitamin D, alone or in combination with targeted vitamin D3 supplementation.
Article
Full-text available
Vitamin D deficiency is often associated with adverse health outcomes in older adults. The circulating 25-hydroxyvitamin D (25(OH)D) status predominately relies on UV exposure. However, the extent of which northerly latitude exasperates deficiency is less explored in ageing. We aimed to investigate vitamin D deficiency in community-dwelling, older adults, residing at latitudes 50–55° north. This study was comprised of 6004 adults, aged >50 years from wave 6 (2012–2013) of the English Longitudinal Study of Ageing (ELSA). Deficiency was categorised by two criteria: Institute of Medicine (IOM) (<30 nmol/L) and Endocrine Society (ES) (<50 nmol/L). The overall prevalence of Institute of Medicine (IOM) and Endocrine Society (ES) definitions of deficiency were 26.4% and 58.7%, respectively. Females (odds ratio (OR) 1.23; CI: 1.04–1.44), those aged 80+ (OR: 1.42; CI: 1.01–1.93), smoking (OR: 1.88; CI: 1.51–2.34); of non-white ethnicity (OR: 3.8; CI:2.39–6.05); being obese (OR: 1.32; CI:1.09–1.58), and of poor self-reported health (OR:1.99; CI:1.33, 2.96), were more likely to be vitamin D deficient (by IOM). Residents in the south of England had a reduced risk of deficiency (OR: 0.78; CI:0.64–0.95), even after adjustment for socioeconomic and traditional predictors (obesity, age, lifestyle, etc.) of vitamin D status. Other factors, such as being retired, having a normal BMI, engaging in regular vigorous physical activity, vitamin D supplement use, sun travel, and summer season were also significantly positive correlates of deficiency. Similar results were observed for the ES cut-off definition. Importantly, more than half of adults aged >50 years had 25(OH)D concentrations <50 nmol/L. These findings demonstrate that low vitamin D status is highly prevalent in older English adults and the crucial importance of public health strategies throughout midlife and older age to achieve optimal vitamin D status.
Article
Full-text available
Objective To investigate serum 25-hydroxyvitamin D (S-25(OH)D) concentration in a multi-ethnic population of northern Norway and determine predictors of S-25(OH)D, including Sami ethnicity. Design Cross-sectional data from the second survey of the Population-based Study on Health and Living Conditions in Regions with Sami and Norwegian Populations (the SAMINOR 2 Clinical Survey, 2012–2014). S-25(OH)D was measured by the IDS-iSYS 25-Hydroxy Vitamin Dˢ assay. Daily dietary intake was assessed using an FFQ. BMI was calculated using weight and height measurements. Setting Ten municipalities of northern Norway (latitude 68°–70°N). Participants Males ( n 2041) and females ( n 2424) aged 40–69 years. Results Mean S-25(OH)D in the study sample was 64·0 nmol/l and median vitamin D intake was 10·3 µg/d. The prevalence of S-25(OH)D<30 nmol/l was 1·9 % and <50 nmol/l was 24·7 %. In sex-specific multivariable linear regression models, older age, blood sample collection in September–October, solarium use, sunbathing holiday, higher alcohol intake (in females), use of cod-liver oil/fish oil supplements, use of vitamin/mineral supplements and higher intakes of vitamin D were significantly associated with higher S-25(OH)D, whereas being a current smoker and obesity were associated with lower S-25(OH)D. These factors explained 21–23 % of the variation in S-25(OH)D. Conclusions There were many modifiable risk factors related to S-25(OH)D, however no clear ethnic differences were found. Even in winter, the low prevalence of vitamin D deficiency found among participants with non-Sami, multi-ethnic Sami and Sami self-perceived ethnicity was likely due to adequate vitamin D intake.
Article
Severe COVID-19 associated pneumonia patients may exhibit features of systemic hyper-inflammation designated under the umbrella term of macrophage activation syndrome (MAS) or cytokine storm, also known as secondary haemophagocytic lymphohistocytosis (sHLH). This is distinct from HLH associated with immunodeficiency states termed primary HLH -with radically different therapy strategies in both situations. COVID-19 infection with MAS typically occurs in subjects with adult respiratory distress syndrome (ARDS) and historically, non-survival in ARDS was linked to sustained IL-6 and IL-1 elevation. We provide a model for the classification of MAS to stratify the MAS-like presentation in COVID-19 pneumonia and explore the complexities of discerning ARDS from MAS. We describe the potential impact of viral load and therapy timing towards improving the outcome of IL-6 antagonism and other immunomodulatory therapies.
Article
Aims: Nordic countries share fairly similar food culture and geographical location as well as common nutrition recommendations. The aim of this paper was to review the latest data on vitamin D status and intake and to describe the national supplementation and food fortification policies to achieve adequate vitamin D intake in the Nordic countries. Methods: The data are based on results derived from a literature search presented in a workshop held in Helsinki in November 2018 and completed by recent studies. Results: Vitamin D policies and the implementation of the recommendations differ among the Nordic countries. Vitamin D fortification policies can be mandatory or voluntary and widespread, moderate or non-existent. Vitamin D supplementation recommendations differ, ranging from all age groups being advised to take supplements to only infants. In the general adult population of the Nordic countries, vitamin D status and intake are better than in the risk groups that are not consuming vitamin D supplements or foods containing vitamin D. Non-Western immigrant populations in all Nordic countries share the problem of vitamin D insufficiency and deficiency. Conclusions: Despite the common nutrition recommendations, there are differences between the Nordic countries in the implementation of the recommendations and policies to achieve adequate vitamin D intake and status. There is a need for wider Nordic collaboration studies as well as strategies to improve vitamin D status, especially in risk groups.
Article
Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) < 50 nmol/l or 20 ng/ml), is common in Europe and the Middle East. It occurs in < 20 % of the population in Northern Europe, in 30-60% in Western, Southern and Eastern Europe and up to 80 % in Middle East countries. Severe deficiency (serum 25(OH)D < 30 nmol/l or 12 ng/ml) is found in > 10 % of Europeans. The ECTS advises that the measurement of serum 25(OH)D be standardized e.g. by the Vitamin D Standardization Program. Risk groups include young children, adolescents, pregnant women, older people, especially the institutionalized, and non-western immigrants. Consequences of vitamin D deficiency include mineralization defects and lower bone mineral density causing fractures. Extra-skeletal consequences may be muscle weakness, falls and acute respiratory infection, and are the subject of large ongoing clinical trials. The ECTS advises to improve vitamin D status by food fortification and the use of vitamin D supplements in risk groups. Fortification of foods by adding vitamin D to dairy products, bread and cereals can improve the vitamin D status of the whole population, but quality assurance monitoring is needed to prevent intoxication. Specific risk groups such as infants and children up to 3 years, pregnant women, older persons and non-western immigrants should routinely receive vitamin D supplements. Future research should include genetic studies to better define individual vulnerability for vitamin D deficiency, and Mendelian randomization studies to address the effect of vitamin D deficiency on long term non-skeletal outcomes such as cancer.