Vitamine D et virus?

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Vitamin D Intake May Reduce SARS-CoV-2 Infection Morbidity in Health Care Workers
by Tatiana L. Karonova Nutrients 2022, 14(3), 505;

In the last 2 years, observational studies have shown that a low 25-hydroxyvitamin D (25(OH)D) level affected the severity of infection with the novel coronavirus (COVID-19). This study aimed to analyze the potential effect of vitamin D supplementation in reducing SARS-CoV-2 infection morbidity and severity in health care workers. Of 128 health care workers, 91 (consisting of 38 medical doctors (42%), 38 nurses (42%), and 15 medical attendants (16%)) were randomized into two groups receiving vitamin D supplementation. Participants of group I (n = 45) received water-soluble cholecalciferol at a dose of 50,000 IU/week for 2 consecutive weeks, followed by 5000 IU/day for the rest of the study. Participants of group II (n = 46) received water-soluble cholecalciferol at a dose of 2000 IU/day. For both groups, treatment lasted 3 months.

Baseline serum 25(OH)D level in health care workers varied from 3.0 to 65.1 ng/mL (median, 17.7 (interquartile range, 12.2; 24.7) ng/mL). Vitamin D deficiency, insufficiency, and normal vitamin D status were diagnosed in 60%, 30%, and 10%, respectively. Only 78 subjects completed the study. Vitamin D supplementation was associated with an increase in serum 25(OH)D level, but only intake of 5000 IU/day was accompanied by normalization of serum 25(OH)D level, which occurred in 53% of cases. Neither vitamin D intake nor vitamin D deficiency/insufficiency were associated with a decrease in SARS-CoV-2 morbidity (odds ratio = 2.27; 95% confidence interval, 0.72 to 7.12). However, subjects receiving high-dose vitamin D had only asymptomatic SARS-CoV-2 in 10 (26%) cases; at the same time, participants who received 2000 IU/day showed twice as many SARS-CoV-2 cases, with mild clinical features in half of them.

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Traduction de l'étude

L'apport en vitamine D peut réduire la morbidité de l'infection par le SRAS-CoV-2 chez les travailleurs de la santé
par Tatiana L. Karonova Nutrients 2022, 14(3), 505 ;

Au cours des 2 dernières années, des études observationnelles ont montré qu'un faible taux de 25-hydroxyvitamine D (25(OH)D) affectait la sévérité de l'infection par le nouveau coronavirus (COVID-19). Cette étude visait à analyser l'effet potentiel de la supplémentation en vitamine D sur la réduction de la morbidité et de la gravité de l'infection par le SRAS-CoV-2 chez les travailleurs de la santé. Sur 128 travailleurs de la santé, 91 (composés de 38 médecins (42 %), 38 infirmières (42 %) et 15 aides-soignants (16 %)) ont été randomisés en deux groupes recevant une supplémentation en vitamine D. Les participants du groupe I (n = 45) ont reçu du cholécalciférol hydrosoluble à une dose de 50 000 UI/semaine pendant 2 semaines consécutives, suivie de 5 000 UI/jour pendant le reste de l'étude. Les participants du groupe II (n = 46) ont reçu du cholécalciférol hydrosoluble à une dose de 2000 UI/jour. Pour les deux groupes, le traitement a duré 3 mois.

Le taux sérique de base de 25(OH)D chez les travailleurs de la santé variait de 3,0 à 65,1 ng/mL (médiane, 17,7 (intervalle interquartile, 12,2 ; 24,7) ng/mL). Une carence en vitamine D, une insuffisance et un statut normal en vitamine D ont été diagnostiqués chez 60 %, 30 % et 10 %, respectivement. Seuls 78 sujets ont terminé l'étude. La supplémentation en vitamine D a été associée à une augmentation du taux sérique de 25(OH)D, mais seule la prise de 5000 UI/jour s'est accompagnée d'une normalisation du taux sérique de 25(OH)D, qui s'est produite dans 53 % des cas. Ni l'apport en vitamine D ni la carence/insuffisance en vitamine D n'ont été associées à une diminution de la morbidité du SRAS-CoV-2 (rapport de cotes = 2,27 ; intervalle de confiance à 95 %, 0,72 à 7,12). Cependant, les sujets recevant de la vitamine D à forte dose n'avaient que le SRAS-CoV-2 asymptomatique dans 10 (26 %) cas ; dans le même temps, les participants qui ont reçu 2000 UI/jour ont montré deux fois plus de cas de SRAS-CoV-2, avec des caractéristiques cliniques bénignes chez la moitié d'entre eux.

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Serious vitamin D deficiency in healthcare workers during the COVID-19 pandemic
Takanori Funaki BMJ Nutr Prev health 2022

Several reports suggest that vitamin D (VitD) deficiency could increase the predisposition to systemic infection, including respiratory tract infections and impaired immune response.1–4 A recent meta-analysis demonstrated that VitD supplementation can reduce the risk of respiratory tract infections overall based on data from randomised controlled trials.5 Moreover, an article reported a possible association of VitD level with cytokine storm and unregulated inflammation in elderly patients with COVID-19.6 It supported the potential protective impact of VitD by enhancing the immune system and possibly reducing the risk of complications associated with cytokine storm and unregulated inflammation in patients with severe COVID-19. VitD is a lipid-soluble vitamin that acts as a ligand to the intranuclear receptor superfamily and plays a significant role in regulating between innate and acquired immunity.1 25-Hydroxy vitamin D (25(OH)D) is the major circulating form of VitD in humans and currently accepted as the best marker of VitD status.7 To date, there are only a few reports focusing on nutritional status including 25(OH)D in healthcare workers (HCWs) during the COVID-19 pandemic.8

During the COVID-19 pandemic, we conducted a prospective observational study to evaluate several blood markers in HCWs at high risk of SARS-CoV-2 infection at the National Center for Child Health and Development in Tokyo, Japan.7 Blood sampling was performed from the enrolled participants from 1 March 2021 to 5 March 2021, and all clinical laboratory testing of the blood including VitD, zinc and natural killer (NK) cell activity were examined at the SRL Hachioji Laboratory Complex, in Tokyo, Japan. 25(OH)D was measured using chemiluminescent enzyme immunoassay, and serum zinc level was determined using the colorimetric method. Also, chromium-51 release assay was used to assess the NK cell activity. We analysed the relationship between gender and VitD levels using the Fisher’s exact test. In addition, the correlationship between VitD levels and age was calculated by the Pearson’s product–moment correlation coefficient and that between VitD levels and NK cell activity by the Spearman’s rank correlation coefficient. All the statistical analyses were performed using SPSS V.22.0 software package (IBM). A two-sided p<0.05 was considered statistically significant. In the study, 361 HCWs were enrolled, of whom 274 (75.9%) were women. The median age was 35 years (range, 22–67 years). The measured blood markers are summarised in table 1.

Most of the measured data were within their normal ranges in most cases except for the blood markers of decreased ability to protect against infections. The NK cell activity widely varied between the participants and was below the lower limit of normal in 42.5% (37/87) of the male participants and 58.4% (76/274) of the female participants. However, there was no correlation between the NK cell activity and 25(OH)D level (r=–0.047, p=0.374). The zinc level was deficient in 17.2% (15/87) of the male participants and 27.7% (76/274) of the female participants.

Surprisingly, the 25(OH)D level was remarkably low in our study participants. The 25(OH)D level was deficient (<20 ng/mL) in 89.7% (78/87) of the male participants (figure 1A) and in 92.7% (254/274) of the female participants (figure 1B). In addition, 25.3% (22/87) of the male participants and 48.2% (132/274) of the female participants had severe 25(OH)D deficiency (<10 ng/mL). The rate of the female participants with severe 25(OH)D deficiency was significantly higher than that of the male participants (p=0.001). Additionally, there was no correlation between age and serum 25(OH)D level (r=0.094, p=0.074).

A recent article from the UK showed that HCWs with VitD deficiency were more likely to develop COVID-19.8 In the study population, HCWs in the black, Asian and minority ethnic groups were VitD deficient (70%), compared with Caucasians (30%).8 A study targeting Japanese women aged 39–64 years reported a mean 25(OH)D level of 24.63 ng/mL and that 31.6%, 27.0% and 14.9% of women aged 39–49, 50–59 and 60–64 years, respectively.9

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La ligne noire en pointillés indiquent les seuils de déficit sévère en 25(OH)D.

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Emerging Roles of Vitamin D-Induced Antimicrobial Peptides in Antiviral Innate Immunity
by John H. White Nutrients 2022, 14(2), 284;

Vitamin D deficiency, characterized by low circulating levels of calcifediol (25-hydroxyvitamin D, 25D) has been linked to increased risk of infections of bacterial and viral origin. Innate immune cells produce hormonal calcitriol (1,25-dihydroxyvitamin D, 1,25D) locally from circulating calcifediol in response to pathogen threat and an immune-specific cytokine network. Calcitriol regulates gene expression through its binding to the vitamin D receptor (VDR), a ligand-regulated transcription factor. The hormone-bound VDR induces the transcription of genes integral to innate immunity including pattern recognition receptors, cytokines, and most importantly antimicrobial peptides (AMPs). Transcription of the human AMP genes β-defensin 2/defensin-β4 (HBD2/DEFB4) and cathelicidin antimicrobial peptide (CAMP) is stimulated by the VDR bound to promoter-proximal vitamin D response elements. HDB2/DEFB4 and the active form of CAMP, the peptide LL-37, which form amphipathic secondary structures, were initially characterized for their antibacterial actively.

Notably, calcitriol signaling induces secretion of antibacterial activity in vitro and in vivo, and low circulating levels of calcifediol are associated with diverse indications characterized by impaired antibacterial immunity such as dental caries and urinary tract infections. However, recent work has also provided evidence that the same AMPs are components of 1,25D-induced antiviral responses, including those against the etiological agent of the COVID-19 pandemic, the SARS-CoV2 coronavirus.

This review surveys the evidence for 1,25D-induced antimicrobial activity in vitro and in vivo in humans and presents our current understanding of the potential mechanisms by which CAMP and HBD2/DEFB4 contribute to antiviral immunity.

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Traduction de l'étude

Rôles émergents des peptides antimicrobiens induits par la vitamine D dans l'immunité innée antivirale
par John H. White Nutrients 2022, 14(2), 284 ;

Une carence en vitamine D, caractérisée par de faibles taux circulants de calcifediol (25-hydroxyvitamine D, 25D) a été associée à un risque accru d'infections d'origine bactérienne et virale. Les cellules immunitaires innées produisent localement du calcitriol hormonal (1,25-dihydroxyvitamine D, 1,25D) à partir du calcifediol circulant en réponse à la menace pathogène et à un réseau de cytokines spécifiques au système immunitaire. Le calcitriol régule l'expression des gènes par sa liaison au récepteur de la vitamine D (VDR), un facteur de transcription régulé par un ligand. Le VDR lié aux hormones induit la transcription de gènes faisant partie intégrante de l'immunité innée, notamment les récepteurs de reconnaissance de formes, les cytokines et, surtout, les peptides antimicrobiens (AMP). La transcription des gènes AMP humains β-défensine 2/défensine-β4 (HBD2/DEFB4) et du peptide antimicrobien cathélicidine (CAMP) est stimulée par le VDR lié aux éléments de réponse de la vitamine D proximaux au promoteur. HDB2/DEFB4 et la forme active de CAMP, le peptide LL-37, qui forment des structures secondaires amphipathiques, ont été initialement caractérisés pour leur activité antibactérienne.

Notamment, la signalisation du calcitriol induit la sécrétion d'une activité antibactérienne in vitro et in vivo, et de faibles niveaux circulants de calcifediol sont associés à diverses indications caractérisées par une immunité antibactérienne altérée telles que les caries dentaires et les infections des voies urinaires. Cependant, des travaux récents ont également fourni la preuve que les mêmes AMP sont des composants des réponses antivirales induites par le 1,25D, y compris celles contre l'agent étiologique de la pandémie de COVID-19, le coronavirus SARS-CoV2.

Cette revue examine les preuves de l'activité antimicrobienne induite par le 1,25D in vitro et in vivo chez l'homme et présente notre compréhension actuelle des mécanismes potentiels par lesquels CAMP et HBD2/DEFB4 contribuent à l'immunité antivirale.

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Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness
Amiel A. Dror PLOS one February 3, 2022

Objective
Studies have demonstrated a potential correlation between low vitamin D status and both an increased risk of infection with SARS-CoV-2 and poorer clinical outcomes. This retrospective study examines if, and to what degree, a relationship exists between pre-infection serum 25-hydroxyvitamin D (25(OH)D) level and disease severity and mortality due to SARS-CoV-2.

Participants
The records of individuals admitted between April 7th, 2020 and February 4th, 2021 to the Galilee Medical Center (GMC) in Nahariya, Israel, with positive polymerase chain reaction (PCR) tests for SARS-CoV-2 (COVID-19) were searched for historical 25(OH)D levels measured 14 to 730 days prior to the positive PCR test.

Design
Patients admitted to GMC with COVID-19 were categorized according to disease severity and level of 25(OH)D. An association between pre-infection 25(OH)D levels, divided between four categories (deficient, insufficient, adequate, and high-normal), and COVID-19 severity was ascertained utilizing a multivariable regression analysis. To isolate the possible influence of the sinusoidal pattern of seasonal 25(OH)D changes throughout the year, a cosinor model was used.

Results
Of 1176 patients admitted, 253 had records of a 25(OH)D level prior to COVID-19 infection. A lower vitamin D status was more common in patients with the severe or critical disease (<20 ng/mL [87.4%]) than in individuals with mild or moderate disease (<20 ng/mL [34.3%] p < 0.001). Patients with vitamin D deficiency (<20 ng/mL) were 14 times more likely to have severe or critical disease than patients with 25(OH)D ≥40 ng/mL (odds ratio [OR], 14; 95% confidence interval [CI], 4 to 51; p < 0.001).

Conclusions
Among hospitalized COVID-19 patients, pre-infection deficiency of vitamin D was associated with increased disease severity and mortality.

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Niveaux de 25-hydroxyvitamine D3 avant l'infection et association avec la gravité de la maladie COVID-19

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Vitamin D, D-binding protein, free vitamin D and COVID-19 mortality in hospitalized patients
Sreedhar Subramanian, The American Journal of Clinical Nutrition, 31 January 2022

Background
Vitamin D deficiency has been associated with worse coronavirus disease 2019 (COVID-19) outcomes but circulating 25-hydroxyvitamin D (25(OH)D) is largely bound to vitamin D binding protein (DBP) or albumin both of which tend to fall in illness making 25(OH)D status hard to interpret. Because of this, measurement of unbound “free” and albumin-bound “bioavailable” 25(OH) D has been proposed.

Objective
We aimed to examine the relationship between vitamin D status and mortality from COVID-19.

Methods
In this observational study conducted in Liverpool, UK, hospitalized COVID-19 patients with surplus sera available for 25(OH)D analysis were studied. Clinical data including age, ethnicity and co-morbidities were extracted from case notes. Serum 25(OH)D, DBP and albumin concentrations were measured. Free and bioavailable 25(OH) D were calculated. Relationships between total, free and bioavailable 25(OH)D and 28-day mortality were analyzed by logistic regression.

Findings
Four hundred and seventy-two patients with COVID-19 were included, of whom 112 (23.7%) died within 28 days. Non-survivors were older (mean age 73, [range 34-98]) than survivors (65, [19-95]; P = 0.003) and more likely male (67%; P = 0.02). The frequency of vitamin D deficiency (25(OH)D <50nmol/L) was similar between non-survivors (71/112 [63.4%]) and survivors (204/360 [56.7%]; P = 0.15) but, after adjustment for age, sex and co-morbidities, increased odds for mortality were present in those with severe deficiency (25(OH)D <25nmol/L), OR 2.37 (95% CI 1.17, 4.78), or high 25(OH)D (≥100nmol/L), OR 4.65 (95% CI 1.51, 14.34) compared with 25(OH)D 50-74 nmol/L (reference). Serum DBP levels were not associated with mortality after adjustment for 25(OH)D, age, sex and co-morbidities. Neither free nor bioavailable 25(OH)D were associated with mortality.

Conclusion:
Vitamin D deficiency as commonly defined by serum 25 (OH)D levels (<50nmol/L) is not associated with increased mortality from COVID-19 but extreme low (<25nmol/L) and high (>100nmol/L) levels may be associated with risk. Neither free nor bioavailable 25(OH) D associate with risk.

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Traduction de l'étude

Vitamine D, D-binding protein, vitamine D libre et mortalité liée au COVID-19 chez les patients hospitalisés
Sreedhar Subramanian, The American Journal of Clinical Nutrition, 31 janvier 2022

Fond
La carence en vitamine D a été associée à de pires résultats de la maladie à coronavirus 2019 (COVID-19), mais la 25-hydroxyvitamine D (25(OH)D) en circulation est largement liée à la protéine de liaison à la vitamine D (DBP) ou à l'albumine, qui ont toutes deux tendance à tomber dans maladie rendant le statut 25(OH)D difficile à interpréter. Pour cette raison, la mesure de la 25(OH) D non liée « libre » et « biodisponible » liée à l'albumine a été proposée.

Objectif
Notre objectif était d'examiner la relation entre le statut en vitamine D et la mortalité par COVID-19.

Méthodes
Dans cette étude observationnelle menée à Liverpool, au Royaume-Uni, des patients COVID-19 hospitalisés avec des sérums excédentaires disponibles pour l'analyse 25(OH)D ont été étudiés. Les données cliniques, y compris l'âge, l'origine ethnique et les comorbidités, ont été extraites des notes de cas. Les concentrations sériques de 25(OH)D, de DBP et d'albumine ont été mesurées. La 25(OH)D libre et biodisponible a été calculée. Les relations entre la 25(OH)D totale, libre et biodisponible et la mortalité à 28 jours ont été analysées par régression logistique.

Résultats
Quatre cent soixante-douze patients atteints de COVID-19 ont été inclus, dont 112 (23,7 %) sont décédés dans les 28 jours. Les non-survivants étaient plus âgés (moyenne d'âge 73 ans, [intervalle 34-98]) que les survivants (65 ans, [19-95] ; P = 0,003) et plus probablement de sexe masculin (67 % ; P = 0,02). La fréquence de la carence en vitamine D (25(OH)D <50nmol/L) était similaire entre les non-survivants (71/112 [63,4 %]) et les survivants (204/360 [56,7 %] ; P = 0,15) mais, après ajustement pour l'âge, le sexe et les comorbidités, un risque accru de mortalité était présent chez les personnes présentant une carence sévère (25(OH)D <25nmol/L), OR 2,37 (IC à 95 % 1,17, 4,78) ou 25(OH) élevé D (≥ 100 nmol/L), OR 4,65 (IC à 95 % 1,51, 14,34) par rapport à 25(OH)D 50-74 nmol/L (référence). Les taux sériques de DBP n'étaient pas associés à la mortalité après ajustement pour le 25(OH)D, l'âge, le sexe et les comorbidités. Ni le 25(OH)D libre ni biodisponible n'ont été associés à la mortalité.

Conclusion:
La carence en vitamine D, telle qu'elle est communément définie par les taux sériques de 25 (OH)D (<50 nmol/L), n'est pas associée à une mortalité accrue due au COVID-19, mais des taux extrêmement faibles (<25 nmol/L) et élevés (>100 nmol/L) peuvent être associé au risque. Ni le 25(OH) D libre ni biodisponible n'est associé à un risque.

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The Immunologic Profile of Vitamin D and Its Role in Different Immune-Mediated Diseases: An Expert Opinion
by Sandro Giannini Nutrients 2022, 14(3), 473;

Historically, vitamin D is recognized as an essential component for the maintenance of the musculoskeletal system. The immunomodulatory role of vitamin D in health and disease has gained much interest in recent years due to the many pathologies that share underlying immunological features where vitamin D has been shown to exert a potential role. Evidence from pre-clinical studies show that vitamin D elicits biological effects on both the innate and adaptive immune systems. Furthermore, in vivo studies have shown that administration of vitamin D can lead to changes in or the development of a range of immune-related diseases. This encourages the hypothesis that data derived from clinical and epidemiological studies connect vitamin D with the incidence and severity of many immune-mediated disorders such as rheumatoid arthritis, diabetes, and infectious diseases. Since some other immune-mediated diseases share similar features to that of viral infection such as COVID-19, in this review, we examined these other areas and the role of vitamin D in these diseases.

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Traduction de l'étude

Le profil immunologique de la vitamine D et son rôle dans différentes maladies à médiation immunitaire : un avis d'expert
par Sandro Giannini Nutriments 2022, 14(3), 473 ;

Historiquement, la vitamine D est reconnue comme un composant essentiel pour le maintien du système musculo-squelettique. Le rôle immunomodulateur de la vitamine D dans la santé et la maladie a suscité beaucoup d'intérêt ces dernières années en raison des nombreuses pathologies qui partagent des caractéristiques immunologiques sous-jacentes où il a été démontré que la vitamine D exerce un rôle potentiel. Les preuves issues d'études précliniques montrent que la vitamine D provoque des effets biologiques sur les systèmes immunitaires inné et adaptatif. De plus, des études in vivo ont montré que l'administration de vitamine D peut entraîner des changements ou le développement d'une gamme de maladies liées au système immunitaire. Cela encourage l'hypothèse selon laquelle les données issues d'études cliniques et épidémiologiques relient la vitamine D à l'incidence et à la gravité de nombreux troubles à médiation immunitaire tels que la polyarthrite rhumatoïde, le diabète et les maladies infectieuses. Étant donné que certaines autres maladies à médiation immunitaire partagent des caractéristiques similaires à celles des infections virales telles que le COVID-19, dans cette revue, nous avons examiné ces autres domaines et le rôle de la vitamine D dans ces maladies.

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Evaluating the Evidence in Clinical Studies of Vitamin D in COVID-19
by Tom D. Thacher Nutrients 2022, 14(3), 464;

Laboratory evidence provides a biological rationale for the benefits of vitamin D in COVID-19, and vitamin D supplementation is associated with reduced risk of respiratory infections. Most of the clinical studies of vitamin D in COVID-19 have been observational, and the most serious problem with observational study design is that of confounding. Observational studies typically assess the relationship of 25(OH)D values with COVID-19 outcomes.

Many conditions associated with low vitamin D status are also associated with worse COVID-19 outcomes. Randomized controlled trials (RCTs) overcome the problem of confounding, typically comparing outcomes between groups receiving vitamin D supplementation or placebo. However, any benefit of vitamin D in COVID-19 may be related to the dose, duration, daily vs. bolus administration, interaction with other treatments, and timing of administration prior to or during the illness.

Serum 25(OH)D values >50 nmol/L have been associated with reduced infection rates, severity of COVID-19, and mortality in observational studies. Few RCTs of vitamin D supplementation have been completed, and they have shown no benefit of vitamin D in hospitalized patients. Vitamin D may benefit those with mild or asymptomatic COVID-19, and those with greater 25(OH)D values may have lower risk of acquiring infection. Because those at greatest risk of COVID-19 are also at greatest risk of vitamin D deficiency, it is reasonable to recommend vitamin D supplementation 15–20 mcg (600–800 IU) daily for the general population during the COVID-19 pandemic. Vitamin D doses greater than 100 mcg (4000 IU) daily should not be used without monitoring serum 25(OH)D and calcium.

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Traduction de l'étude

Évaluation des preuves dans les études cliniques sur la vitamine D dans le COVID-19
par Tom D. Thacher Nutriments 2022, 14(3), 464 ;

Les preuves de laboratoire fournissent une justification biologique des avantages de la vitamine D dans le COVID-19, et la supplémentation en vitamine D est associée à un risque réduit d'infections respiratoires. La plupart des études cliniques sur la vitamine D dans le COVID-19 ont été observationnelles, et le problème le plus grave avec la conception des études observationnelles est celui de la confusion. Les études observationnelles évaluent généralement la relation entre les valeurs de 25(OH)D et les résultats de la COVID-19.

De nombreuses conditions associées à un faible statut en vitamine D sont également associées à de moins bons résultats pour le COVID-19. Les essais contrôlés randomisés (ECR) surmontent le problème de la confusion, comparant généralement les résultats entre les groupes recevant une supplémentation en vitamine D ou un placebo. Cependant, tout avantage de la vitamine D dans le COVID-19 peut être lié à la dose, à la durée, à l'administration quotidienne par rapport au bolus, à l'interaction avec d'autres traitements et au moment de l'administration avant ou pendant la maladie.

Des valeurs sériques de 25(OH)D > 50 nmol/L ont été associées à une réduction des taux d'infection, de la gravité de la COVID-19 et de la mortalité dans les études observationnelles. Peu d'ECR sur la supplémentation en vitamine D ont été achevés et ils n'ont montré aucun avantage de la vitamine D chez les patients hospitalisés. La vitamine D peut être bénéfique pour les personnes atteintes de COVID-19 léger ou asymptomatique, et celles dont les valeurs de 25(OH)D sont supérieures peuvent avoir un risque plus faible de contracter une infection. Étant donné que les personnes les plus à risque de COVID-19 sont également les plus à risque de carence en vitamine D, il est raisonnable de recommander une supplémentation en vitamine D de 15 à 20 mcg (600 à 800 UI) par jour pour la population générale pendant la pandémie de COVID-19. Des doses de vitamine D supérieures à 100 mcg (4 000 UI) par jour ne doivent pas être utilisées sans surveillance de la 25(OH)D et du calcium sériques.

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Vitamin D deficiency aggravates COVID-19: systematic review and meta-analysis
Marcos Pereira Critical Reviews in Food Science and Nutrition Volume 62, 2022 - Issue 5 Pages 1308-1316

There is still limited evidence regarding the influence of vitamin D in people with COVID-19. In this systematic review and meta-analysis, we analyze the association between vitamin D deficiency and COVID-19 severity, via an analysis of the prevalence of vitamin D deficiency and insufficiency in people with the disease. Five online databases—Embase, PubMed, Scopus, Web of Science, ScienceDirect and pre-print Medrevix were searched. The inclusion criteria were observational studies measuring serum vitamin D in adult and elderly subjects with COVID-19. The main outcome was the prevalence of vitamin D deficiency in severe cases of COVID-19. We carried out a meta-analysis with random effect measures. We identified 1542 articles and selected 27.

Vitamin D deficiency was not associated with a higher chance of infection by COVID-19 (OR = 1.35; 95% CI = 0.80–1.88), but we identified that severe cases of COVID-19 present 64% (OR = 1.64; 95% CI = 1.30–2.09) more vitamin D deficiency compared with mild cases. A vitamin D concentration insufficiency increased hospitalization (OR = 1.81, 95% CI = 1.41–2.21) and mortality from COVID-19 (OR = 1.82, 95% CI = 1.06–2.58). We observed a positive association between vitamin D deficiency and the severity of the disease.