{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:05:37Z","timestamp":1760234737297,"version":"build-2065373602"},"reference-count":64,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,6,9]],"date-time":"2021-06-09T00:00:00Z","timestamp":1623196800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background and aims: Vitamin D inadequacy may be involved in the mechanisms of SARS-CoV-2 infection and in potential risk factors for disease propagation or control of coronavirus disease 2019 (COVID-19). This study assessed a short-term evolution of vitamin D status and its influence upon different clinical parameters in critically ill patients with COVID-19. Methods: A prospective analytical study in which 37 critically ill volunteers between 41 and 71 years of age with COVID-19 were evaluated at baseline and three days of intensive care unit (ICU) stay. 25-OH-D3 and 25-OH-D2 were analyzed by liquid chromatography\u2013tandem mass spectrometry and total 25-OH-D levels were calculated as the sum of both. Results: All patients presented low 25-OH-D levels at baseline, decreasing total 25-OH-D (p = 0.011) mainly through 25-OH-D2 (p = 0.006) levels during ICU stay. 25-OH-D2 levels decreased a mean of 41.6% \u00b1 89.6% versus 7.0% \u00b1 23.4% for the 25-OH-D3 form during the ICU stay. Patients who did not need invasive mechanical ventilation presented higher levels of 25-OH-D2 at baseline and follow-up. Lower 25-OH-D and 25-OH-D3 levels were associated with higher D-dimer at baseline (p = 0.003; p = 0.001) and at follow up (p = 0.029), higher procalcitonin levels (p = 0.002; p = 0.018) at follow up, and lower percentage lymphocyte counts (p = 0.044; p = 0.040) during ICU stay. Conclusions: Deficient vitamin D status in critical patients was established at the admission and further worsened after three days of stay. Lower vitamin D levels were related to key altered clinical and biochemical parameters on patients with SARS-CoV-2 infection. Given the different response of the 25-OH-D3 and 25-OH-D2 forms, it would be useful to monitor them on the evolution of the critically ill patient.<\/jats:p>","DOI":"10.3390\/nu13061988","type":"journal-article","created":{"date-parts":[[2021,6,9]],"date-time":"2021-06-09T14:16:04Z","timestamp":1623248164000},"page":"1988","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Bad Prognosis in Critical Ill Patients with COVID-19 during Short-Term ICU Stay regarding Vitamin D Levels"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1407-322X","authenticated-orcid":false,"given":"Lourdes","family":"Herrera-Quintana","sequence":"first","affiliation":[{"name":"Department of Physiology, Institute of Nutrition and Food Technology \u201cJose Mataix\u201d, School of Pharmacy, University of Granada, 18071 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0921-2168","authenticated-orcid":false,"given":"Yenifer","family":"Gamarra-Morales","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute of Nutrition and Food Technology \u201cJose Mataix\u201d, School of Pharmacy, University of Granada, 18071 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0183-6902","authenticated-orcid":false,"given":"H\u00e9ctor","family":"V\u00e1zquez-Lorente","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute of Nutrition and Food Technology \u201cJose Mataix\u201d, School of Pharmacy, University of Granada, 18071 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2516-5226","authenticated-orcid":false,"given":"Jorge","family":"Molina-L\u00f3pez","sequence":"additional","affiliation":[{"name":"Faculty of Education, Psychology and Sports Sciences, University of Huelva, 21007 Huelva, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jos\u00e9","family":"Casta\u00f1o-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Intensive Care Unit, Virgen de las Nieves Hospital, Fuerzas Armadas Avenue, 18014 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7852-6553","authenticated-orcid":false,"given":"Juan Francisco","family":"Machado-Casas","sequence":"additional","affiliation":[{"name":"Intensive Care Unit, Virgen de las Nieves Hospital, Fuerzas Armadas Avenue, 18014 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5014-5644","authenticated-orcid":false,"given":"Ram\u00f3n","family":"Coca-Z\u00fa\u00f1iga","sequence":"additional","affiliation":[{"name":"Intensive Care Unit, Virgen de las Nieves Hospital, Fuerzas Armadas Avenue, 18014 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jos\u00e9 Miguel","family":"P\u00e9rez-Villares","sequence":"additional","affiliation":[{"name":"Intensive Care Unit, Virgen de las Nieves Hospital, Fuerzas Armadas Avenue, 18014 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elena","family":"Planells","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute of Nutrition and Food Technology \u201cJose Mataix\u201d, School of Pharmacy, University of Granada, 18071 Granada, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1373","DOI":"10.1016\/j.jiph.2020.06.021","article-title":"Role of Vitamin D in Preventing of COVID-19 Infection, Progression and Severity","volume":"13","author":"Ali","year":"2020","journal-title":"J. Infect. Public Health"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"De las Heras, N., Mart\u00edn Gim\u00e9nez, V.M., Ferder, L., Manucha, W., and Lahera, V. (2020). Implications of Oxidative Stress and Potential Role of Mitochondrial Dysfunction in COVID-19: Therapeutic Effects of Vitamin D. Antioxidants, 9.","DOI":"10.3390\/antiox9090897"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1080\/22221751.2020.1770129","article-title":"Profiling Serum Cytokines in COVID-19 Patients Reveals IL-6 and IL-10 Are Disease Severity Predictors","volume":"9","author":"Han","year":"2020","journal-title":"Emerg. Microbes Infect."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1157","DOI":"10.1007\/s00210-020-01911-4","article-title":"Vitamin D Can Prevent COVID-19 Infection-Induced Multiple Organ Damage","volume":"393","author":"Aygun","year":"2020","journal-title":"Naunyn. Schmiedebergs Arch. Pharmacol."},{"key":"ref_5","first-page":"R146","article-title":"Oxidative Stress Is Increased in Critically Ill Patients According to Antioxidant Vitamins Intake, Independent of Severity: A Cohort Study","volume":"10","author":"Aguayo","year":"2006","journal-title":"Crit. Care"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1186\/s13054-019-2450-5","article-title":"Pyroglutamic Acidosis by Glutathione Regeneration Blockage in Critical Patients with Septic Shock","volume":"23","author":"Gamarra","year":"2019","journal-title":"Crit. Care"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1002\/jpen.1953","article-title":"Evaluation of Nutrition Risk and Its Association with Mortality Risk in Severely and Critically Ill COVID-19 Patients","volume":"45","author":"Zhao","year":"2020","journal-title":"J. Parenter. Enter. Nutr."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"110834","DOI":"10.1016\/j.nut.2020.110834","article-title":"Nutrition Support in the Time of SARS-CoV-2 (COVID-19)","volume":"74","author":"Laviano","year":"2020","journal-title":"Nutrition"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1631","DOI":"10.1016\/j.clnu.2020.03.022","article-title":"ESPEN Expert Statements and Practical Guidance for Nutritional Management of Individuals with SARS-CoV-2 Infection","volume":"39","author":"Barazzoni","year":"2020","journal-title":"Clin. Nutr."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Zabetakis, I., Lordan, R., Norton, C., and Tsoupras, A. (2020). COVID-19: The Inflammation Link and the Role of Nutrition in Potential Mitigation. Nutrients, 12.","DOI":"10.3390\/nu12051466"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"110835","DOI":"10.1016\/j.nut.2020.110835","article-title":"Early Nutritional Supplementation in Non-Critically Ill Patients Hospitalized for the 2019 Novel Coronavirus Disease (COVID-19): Rationale and Feasibility of a Shared Pragmatic Protocol","volume":"74","author":"Caccialanza","year":"2020","journal-title":"Nutrition"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1002\/ncp.10566","article-title":"Relevant Nutrition Therapy in COVID-19 and the Constraints on Its Delivery by a Unique Disease Process","volume":"35","author":"Patel","year":"2020","journal-title":"Nutr. Clin. Pract."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Alexander, J., Tinkov, A., Strand, T.A., Alehagen, U., Skalny, A., and Aaseth, J. (2020). Early Nutritional Interventions with Zinc, Selenium and Vitamin D for Raising Anti-Viral Resistance Against Progressive COVID-19. Nutrients, 12.","DOI":"10.3390\/nu12082358"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/j.trac.2016.02.005","article-title":"Analysis of Vitamin D Metabolites by Liquid Chromatography-Tandem Mass Spectrometry","volume":"84","year":"2016","journal-title":"TrAC Trends Anal. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1654","DOI":"10.1016\/j.jchromb.2009.11.026","article-title":"Advances in Determination of Vitamin D Related Compounds in Biological Samples Using Liquid Chromatography\u2013Mass Spectrometry: A Review","volume":"878","author":"Higashi","year":"2010","journal-title":"J. Chromatogr. B"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1177\/0148607115587948","article-title":"Clinical Trial of Vitamin D 2 vs. D 3 Supplementation in Critically Ill Pediatric Burn Patients","volume":"41","author":"Gottschlich","year":"2017","journal-title":"J. Parenter. Enter. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Grant, W.B., Lahore, H., McDonnell, S.L., Baggerly, C.A., French, C.B., Aliano, J.L., and Bhattoa, H.P. (2020). Evidence That Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients, 12.","DOI":"10.20944\/preprints202003.0235.v2"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"117808","DOI":"10.1016\/j.lfs.2020.117808","article-title":"Lungs as Target of COVID-19 Infection: Protective Common Molecular Mechanisms of Vitamin D and Melatonin as a New Potential Synergistic Treatment","volume":"254","author":"Inserra","year":"2020","journal-title":"Life Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/j.arteri.2020.05.003","article-title":"Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection","volume":"32","author":"Mansur","year":"2020","journal-title":"Cl\u00edn. Investig. Arterioscler."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e107","DOI":"10.7861\/clinmed.2020-0301","article-title":"Does Vitamin D Deficiency Increase the Severity of COVID-19?","volume":"20","author":"Weir","year":"2020","journal-title":"Clin. Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"620","DOI":"10.1136\/jclinpath-2012-201301","article-title":"Vitamin D: A Negative Acute Phase Reactant","volume":"66","author":"Waldron","year":"2013","journal-title":"J. Clin. Pathol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1373\/clinchem.2011.176545","article-title":"Accuracy of 6 Routine 25-Hydroxyvitamin D Assays: Influence of Vitamin D Binding Protein Concentration","volume":"58","author":"Heijboer","year":"2012","journal-title":"Clin. Chem."},{"key":"ref_23","first-page":"e2159","article-title":"Vitamin D and Covid-19: From Potential Therapeutic Effects to Unanswered Questions","volume":"31","author":"Marashi","year":"2020","journal-title":"Rev. Med. Virol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"R133","DOI":"10.1530\/EJE-20-0665","article-title":"Mechanisms in endocrinology: Vitamin D and COVID-19","volume":"183","author":"Bilezikian","year":"2020","journal-title":"Eur. J. Endocrinol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"322","DOI":"10.1186\/s12967-020-02488-5","article-title":"The Importance of Vitamin d Metabolism as a Potential Prophylactic, Immunoregulatory and Neuroprotective Treatment for COVID-19","volume":"18","author":"Xu","year":"2020","journal-title":"J. Transl. Med."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"765","DOI":"10.1007\/s40618-020-01370-x","article-title":"Vitamin D Deficiency as a Predictor of Poor Prognosis in Patients with Acute Respiratory Failure Due to COVID-19","volume":"44","author":"Carpagnano","year":"2020","journal-title":"J. Endocrinol. Investig."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e2019722","DOI":"10.1001\/jamanetworkopen.2020.19722","article-title":"Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results","volume":"3","author":"Meltzer","year":"2020","journal-title":"JAMA Netw. Open"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1911","DOI":"10.1210\/jc.2011-0385","article-title":"Evaluation, Treatment, and Prevention of Vitamin D Deficiency: An Endocrine Society Clinical Practice Guideline","volume":"96","author":"Holick","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1097\/CM9.0000000000000866","article-title":"Interpretations of \u201cDiagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (Trial Version 7)\u201d","volume":"133","author":"Zhao","year":"2020","journal-title":"Chin. Med. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1037\/0033-2909.112.1.155","article-title":"A Power Primer","volume":"112","author":"Cohen","year":"1992","journal-title":"Psychol. Bull."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1016\/j.chest.2020.08.2065","article-title":"Male Sex, Severe Obesity, Older Age, and Chronic Kidney Disease Are Associated With COVID-19 Severity and Mortality in New York City","volume":"159","author":"Rapp","year":"2020","journal-title":"Chest"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1790","DOI":"10.1038\/s41366-020-0597-4","article-title":"COVID-19 and the Role of Chronic Inflammation in Patients with Obesity","volume":"44","author":"Chiappetta","year":"2020","journal-title":"Int. J. Obes."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1080\/10408363.2020.1770685","article-title":"Biomarkers associated with COVID-19 disease progression","volume":"57","author":"Ponti","year":"2020","journal-title":"Crit. Rev. Clin. Lab. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1097\/MCC.0000000000000328","article-title":"Vitamin D and Critical Illness Outcomes","volume":"22","author":"Christopher","year":"2016","journal-title":"Curr. Opin. Crit. Care"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"R47","DOI":"10.1186\/cc13790","article-title":"Vitamin D Status and Its Association with Season, Hospital and Sepsis Mortality in Critical Illness","volume":"18","author":"Amrein","year":"2014","journal-title":"Crit. Care"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1007\/s11154-017-9424-1","article-title":"The Vitamin D Deficiency Pandemic: Approaches for Diagnosis, Treatment and Prevention","volume":"18","author":"Holick","year":"2017","journal-title":"Rev. Endocr. Metab. Disord."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Kaufman, H.W., Niles, J.K., Kroll, M.H., Bi, C., and Holick, M.F. (2020). SARS-CoV-2 Positivity Rates Associated with Circulating 25-Hydroxyvitamin D Levels. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0239252"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"513","DOI":"10.3389\/fpubh.2020.00513","article-title":"A Basic Review of the Preliminary Evidence That COVID-19 Risk and Severity Is Increased in Vitamin D Deficiency","volume":"8","author":"Benskin","year":"2020","journal-title":"Front. Public Health"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.1007\/s40520-020-01570-8","article-title":"The Role of Vitamin D in the Prevention of Coronavirus Disease 2019 Infection and Mortality","volume":"32","author":"Ilie","year":"2020","journal-title":"Aging Clin. Exp. Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2141","DOI":"10.1007\/s40520-020-01677-y","article-title":"Evidence for possible association of vitamin D status with cytokine storm and unregulated inflammation in COVID-19 patients","volume":"32","author":"Daneshkhah","year":"2020","journal-title":"Aging Clin. Exp. Res."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"P23","DOI":"10.1530\/EJE-18-0736","article-title":"Current vitamin D status in European and Middle East coun-tries and strategies to prevent vitamin D deficiency: A position statement of the European Calcified Tissue Society","volume":"180","author":"Lips","year":"2019","journal-title":"Eur. J. Endocrinol."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Maghbooli, Z., Sahraian, M.A., Ebrahimi, M., Pazoki, M., Kafan, S., Tabriz, H.M., Hadadi, A., Montazeri, M., Nasiri, M., and Shirvani, A. (2020). Vitamin D Sufficiency, a Serum 25-Hydroxyvitamin D at Least 30 Ng\/ML Reduced Risk for Adverse Clinical Outcomes in Patients with COVID-19 Infection. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0239799"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2469","DOI":"10.1016\/j.clnu.2020.10.055","article-title":"Vitamin D 25OH Deficiency in COVID-19 Patients Admitted to a Tertiary Referral Hospital","volume":"40","author":"Cereda","year":"2020","journal-title":"Clin. Nutr."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Vassiliou, A.G., Jahaj, E., Pratikaki, M., Orfanos, S.E., Dimopoulou, I., and Kotanidou, A. (2020). Low 25-Hydroxyvitamin D Levels on Admission to the Intensive Care Unit May Predispose COVID-19 Pneumonia Patients to a Higher 28-Day Mortality Risk: A Pilot Study on a Greek ICU Cohort. Nutrients, 12.","DOI":"10.3390\/nu12123773"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"V\u00e1zquez-Lorente, H., Herrera-Quintana, L., Molina-L\u00f3pez, J., Gamarra-Morales, Y., L\u00f3pez-Gonz\u00e1lez, B., Miralles-Adell, C., and Planells, E. (2020). Response of Vitamin D after Magnesium Intervention in a Postmenopausal Population from the Province of Granada, Spain. Nutrients, 12.","DOI":"10.3390\/nu12082283"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"2736","DOI":"10.1210\/jc.2014-1069","article-title":"Higher 25(OH)D2 Is Associated with Lower 25(OH)D3 and 1,25(OH)2D3","volume":"99","author":"Swanson","year":"2014","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Wang, L., Liu, X., Hou, J., Wei, D., Liu, P., Fan, K., Zhang, L., Nie, L., Li, X., and Huo, W. (2020). Serum Vitamin D Affected Type 2 Diabetes Though Altering Lipid Profile and Modified the Effects of Testosterone on Diabetes Status. Nutrients, 13.","DOI":"10.3390\/nu13010090"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1129","DOI":"10.1017\/S0950268806007175","article-title":"Epidemic Influenza and Vitamin D","volume":"134","author":"Cannell","year":"2006","journal-title":"Epidemiol. Infect."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1007\/s00134-021-06346-w","article-title":"COVID-19 Increased the Risk of ICU-Acquired Bloodstream Infections: A Case\u2013Cohort Study from the Multicentric OUTCOMEREA Network","volume":"47","author":"Buetti","year":"2021","journal-title":"Intensive Care Med."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Infante, M., Buoso, A., Pieri, M., Lupisella, S., Nuccetelli, M., Bernardini, S., Fabbri, A., Iannetta, M., Andreoni, M., and Colizzi, V. (2021). Low Vitamin D Status at Admission as a Risk Factor for Poor Survival in Hospitalized Patients with COVID-19: An Italian Retrospective Study. J. Am. Coll. Nutr., 1\u201316.","DOI":"10.1080\/07315724.2021.1877580"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"694","DOI":"10.1093\/ajcn\/84.4.694","article-title":"The Case against Ergocalciferol (Vitamin D2) as a Vitamin Supplement","volume":"84","author":"Houghton","year":"2006","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"e1913","DOI":"10.1210\/clinem\/dgz290","article-title":"The D-Sparaging of Vitamin D2: How Physiologically and Pharmacologically Relevant Is It for the Clinician?","volume":"105","author":"Holick","year":"2020","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Bigman, G. (2020). Vitamin D Metabolites, D3 and D2, and Their Independent Associations with Depression Symptoms among Adults in the United States. Nutr. Neurosci., 1\u20139.","DOI":"10.1080\/1028415X.2020.1794422"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"301","DOI":"10.3389\/fmed.2020.00301","article-title":"Immune-Inflammatory Parameters in COVID-19 Cases: A Systematic Review and Meta-Analysis","volume":"7","author":"Feng","year":"2020","journal-title":"Front. Med."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1002\/ajh.25829","article-title":"Hematological Findings and Complications of COVID -19","volume":"95","author":"Terpos","year":"2020","journal-title":"Am. J. Hematol."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.2337\/dc11-1944","article-title":"Circulating 25-Hydroxyvitamin D Concentrations Are Correlated with Cardiometabolic Risk Among American Black and White Adolescents Living in a Year-Round Sunny Climate","volume":"35","author":"Parikh","year":"2012","journal-title":"Diabetes Care"},{"key":"ref_57","first-page":"36","article-title":"Determinants of Vitamin D Activation in Patients with Acute Coronary Syndromes and Its Correlation with Inflammatory Markers","volume":"31","author":"Verdoia","year":"2020","journal-title":"Nutr. Metab. Cardiovasc. Dis."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"584","DOI":"10.1016\/j.clnu.2018.07.009","article-title":"Monitoring Nutrition in the ICU","volume":"38","author":"Berger","year":"2019","journal-title":"Clin. Nutr."},{"key":"ref_59","first-page":"1418","article-title":"Current Trends in the Analytical Determination of Vitamin D","volume":"36","author":"Planells","year":"2019","journal-title":"Nutr. Hosp."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"1011","DOI":"10.1016\/j.clnu.2012.04.009","article-title":"The Prevalence of Vitamin Deficiency in Clinical Practice Is Assay-Dependent","volume":"31","year":"2012","journal-title":"Clin. Nutr."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.cca.2014.07.007","article-title":"Critical Care and Vitamin D Status Assessment: What about Immunoassays and Calculated Free 25OH-D?","volume":"437","author":"Rousseau","year":"2014","journal-title":"Clin. Chim. Acta"},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"105771","DOI":"10.1016\/j.jsbmb.2020.105771","article-title":"Vitamin D and Survival in COVID-19 Patients: A Quasi-Experimental Study","volume":"204","author":"Annweiler","year":"2020","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"105751","DOI":"10.1016\/j.jsbmb.2020.105751","article-title":"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","volume":"203","author":"Miranda","year":"2020","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"856","DOI":"10.1038\/s41430-020-0661-0","article-title":"Perspective: Improving Vitamin D Status in the Management of COVID-19","volume":"74","author":"Ebadi","year":"2020","journal-title":"Eur. J. Clin. 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