Association between Average Vitamin D Levels and COVID-19 Mortality in 19 European Countries—A Population-Based Study

DOI record: { "DOI": "10.3390/nu15224818", "ISSN": [ "2072-6643" ], "URL": "http://dx.doi.org/10.3390/nu15224818", "abstract": "<jats:p>Early epidemic reports have linked low average 25(OH) vitamin D levels with increased COVID-19 mortality. However, there has been limited updated research on 25(OH) vitamin D and its impact on COVID-19 mortality. This study aimed to update the initial report studying the link between vitamin D deficiency and COVID-19 mortality by using multi-country data in 19 European countries up to the middle of June 2023. COVID-19 data for 19 European countries included in this study were downloaded from Our World in Data from 1 March 2020, to 14 June 2023, and were included in the statistical analysis. The 25(OH) vitamin D average data were collected by conducting a literature review. A generalized estimation equation model was used to model the data. Compared to European countries with 25(OH) vitamin D levels of ≤50 nmol/L, European countries with 25(OH) vitamin D average levels greater than &gt;50 nmol/L had lower COVID-19 mortality rates (RR = 0.794, 95% CI: 0.662–0.953). A statistically significant negative Spearman rank correlation was observed between 25(OH) vitamin D average levels and COVID-19 mortality. We also found significantly lower COVID-19 mortality rates in countries with high average 25(OH) vitamin D levels. Randomized trials on vitamin D supplementation are needed. In the meantime, the issue of vitamin D use should be debated in relation to the ongoing discussions of national post-COVID-19 resilience against future pandemics.</jats:p>", "alternative-id": [ "nu15224818" ], "author": [ { "affiliation": [ { "name": "Cancer Intelligence, Cancer Research UK, Oxford OX4 9GZ, UK" } ], "family": "Ahmad", "given": "Amar S.", "sequence": "first" }, { "ORCID": "http://orcid.org/0000-0002-7316-5530", "affiliation": [ { "name": "Public Health Research Center, New York University Abu Dhabi, Abu Dhabi P.O. Box 129188, United Arab Emirates" } ], "authenticated-orcid": false, "family": "Juber", "given": "Nirmin F.", "sequence": "additional" }, { "affiliation": [ { "name": "Academic Unit of Medical Education, University of Southampton, Southampton SO17 1BJ, UK" } ], "family": "Al-Naseri", "given": "Heba", "sequence": "additional" }, { "ORCID": "http://orcid.org/0000-0002-4718-595X", "affiliation": [ { "name": "Department of Statistics, Ludwig Maximilian University of Munich, 80539 München, Germany" } ], "authenticated-orcid": false, "family": "Heumann", "given": "Christian", "sequence": "additional" }, { "affiliation": [ { "name": "MRC Epidemiology Unit, University of Cambridge, Cambridge CB2 0SL, UK" } ], "family": "Ali", "given": "Raghib", "sequence": "additional" }, { "affiliation": [ { "name": "Barts Cancer Institute, Queen Mary University of London, London EC1M 6AU, UK" } ], "family": "Oliver", "given": "Tim", "sequence": "additional" } ], "container-title": "Nutrients", "container-title-short": "Nutrients", "content-domain": { "crossmark-restriction": false, "domain": [] }, "created": { "date-parts": [ [ 2023, 11, 17 ] ], "date-time": "2023-11-17T14:23:43Z", "timestamp": 1700231023000 }, "deposited": { "date-parts": [ [ 2023, 11, 17 ] ], "date-time": "2023-11-17T15:01:35Z", "timestamp": 1700233295000 }, "indexed": { "date-parts": [ [ 2023, 11, 18 ] ], "date-time": "2023-11-18T00:39:18Z", "timestamp": 1700267958952 }, "is-referenced-by-count": 0, "issue": "22", "issued": { "date-parts": [ [ 2023, 11, 17 ] ] }, "journal-issue": { "issue": "22", "published-online": { "date-parts": [ [ 2023, 11 ] ] } }, "language": "en", "license": [ { "URL": "https://creativecommons.org/licenses/by/4.0/", "content-version": "vor", "delay-in-days": 0, "start": { "date-parts": [ [ 2023, 11, 17 ] ], "date-time": "2023-11-17T00:00:00Z", "timestamp": 1700179200000 } } ], "link": [ { "URL": "https://www.mdpi.com/2072-6643/15/22/4818/pdf", "content-type": "unspecified", "content-version": "vor", "intended-application": "similarity-checking" } ], "member": "1968", "original-title": [], "page": "4818", "prefix": "10.3390", "published": { "date-parts": [ [ 2023, 11, 17 ] ] }, "published-online": { "date-parts": [ [ 2023, 11, 17 ] ] }, "publisher": "MDPI AG", "reference": [ { "DOI": "10.1016/S0140-6736(20)30211-7", "article-title": "Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: A descriptive study", "author": "Chen", "doi-asserted-by": "crossref", "first-page": "507", "journal-title": "Lancet", "key": "ref_1", "volume": "395", "year": "2020" }, { "DOI": "10.1016/S2589-7500(20)30026-1", "article-title": "Early epidemiological analysis of the coronavirus disease 2019 outbreak based on crowdsourced data: A population-level observational study", "author": "Sun", "doi-asserted-by": "crossref", "first-page": "e201", "journal-title": "Lancet Digit. Health", "key": "ref_2", "volume": "2", "year": "2020" }, { "DOI": "10.1056/NEJMoa2001316", "article-title": "Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia", "author": "Li", "doi-asserted-by": "crossref", "first-page": "1199", "journal-title": "N. Engl. J. Med.", "key": "ref_3", "volume": "382", "year": "2020" }, { "DOI": "10.1007/s10654-022-00853-w", "article-title": "Infection fatality rate of COVID-19 in community-dwelling elderly populations", "author": "Axfors", "doi-asserted-by": "crossref", "first-page": "235", "journal-title": "Eur. J. Epidemiol.", "key": "ref_4", "volume": "37", "year": "2022" }, { "DOI": "10.1038/s41591-020-0961-x", "article-title": "COVID-19 in Africa: The spread and response", "author": "Tshangela", "doi-asserted-by": "crossref", "first-page": "999", "journal-title": "Nat. Med.", "key": "ref_5", "volume": "26", "year": "2020" }, { "DOI": "10.1136/bmj.m3038", "article-title": "COVID-19: Excess deaths point to hidden toll in South Africa as cases surge", "author": "Dyer", "doi-asserted-by": "crossref", "first-page": "m3038", "journal-title": "BMJ", "key": "ref_6", "volume": "370", "year": "2020" }, { "DOI": "10.1111/tmi.13575", "article-title": "Understanding varying COVID-19 mortality rates reported in Africa compared to Europe, Americas and Asia", "author": "Okonji", "doi-asserted-by": "crossref", "first-page": "716", "journal-title": "Trop. Med. Int. Health", "key": "ref_7", "volume": "26", "year": "2021" }, { "DOI": "10.1080/03009734.2020.1828513", "article-title": "Excess deaths from COVID-19 correlate with age and socio-economic status. A database study in the Stockholm region", "author": "Strang", "doi-asserted-by": "crossref", "first-page": "297", "journal-title": "Upsala J. Med. Sci.", "key": "ref_8", "volume": "125", "year": "2020" }, { "DOI": "10.1007/s11356-020-10689-0", "article-title": "Pollution, economic growth, and COVID-19 deaths in India: A machine learning evidence", "author": "Mele", "doi-asserted-by": "crossref", "first-page": "2669", "journal-title": "Environ. Sci. Pollut. Res. Int.", "key": "ref_9", "volume": "28", "year": "2020" }, { "DOI": "10.1111/1475-5890.12234", "article-title": "The COVID-19 Economic Crisis", "author": "Cloyne", "doi-asserted-by": "crossref", "first-page": "489", "journal-title": "Fisc. Stud.", "key": "ref_10", "volume": "41", "year": "2020" }, { "DOI": "10.1016/j.nut.2021.111441", "article-title": "A critical update on the role of mild and serious vitamin D deficiency prevalence and the COVID-19 epidemic in Europe", "author": "Bakaloudi", "doi-asserted-by": "crossref", "first-page": "111441", "journal-title": "Nutrition", "key": "ref_11", "volume": "93", "year": "2022" }, { "DOI": "10.1017/S0007114517000435", "article-title": "Malnutrition is associated with increased mortality in older adults regardless of the cause of death", "author": "Rosenblad", "doi-asserted-by": "crossref", "first-page": "532", "journal-title": "Br. J. Nutr.", "key": "ref_12", "volume": "117", "year": "2017" }, { "DOI": "10.4103/bbrj.bbrj_69_18", "article-title": "The relationship between nutrition and infectious diseases: A review", "author": "Farhadi", "doi-asserted-by": "crossref", "first-page": "168", "journal-title": "Biomed. Biotechnol. Res. J.", "key": "ref_13", "volume": "2", "year": "2018" }, { "DOI": "10.1097/MAJ.0000000000000360", "article-title": "Impact of vitamin D on infectious disease", "author": "Kearns", "doi-asserted-by": "crossref", "first-page": "245", "journal-title": "Am. J. Med. Sci.", "key": "ref_14", "volume": "349", "year": "2015" }, { "article-title": "Vitamin D and chronic kidney disease: Insights on lipid metabolism of tubular epithelial cell and macrophages in tubulointerstitial fibrosis", "author": "Basso", "first-page": "499", "journal-title": "Front. Physiol.", "key": "ref_15", "volume": "14", "year": "2023" }, { "DOI": "10.4161/derm.24494", "article-title": "Sunlight and Vitamin D: A global perspective for health", "author": "Wacker", "doi-asserted-by": "crossref", "first-page": "51", "journal-title": "Derm. Endocrinol.", "key": "ref_16", "volume": "5", "year": "2013" }, { "DOI": "10.3390/ijms19082419", "doi-asserted-by": "crossref", "key": "ref_17", "unstructured": "Gruber-Bzura, B.M. (2018). Vitamin D and Influenza-Prevention or Therapy?. Int. J. Mol. Sci., 19." }, { "DOI": "10.1136/bmj.i6583", "article-title": "Vitamin D supplementation to prevent acute respiratory tract infections: Systematic review and meta-analysis of individual participant data", "author": "Martineau", "doi-asserted-by": "crossref", "first-page": "i6583", "journal-title": "BMJ", "key": "ref_18", "volume": "356", "year": "2017" }, { "article-title": "Vitamin D supplementation to prevent acute respiratory infections: Systematic review and meta-analysis of aggregate data from randomised controlled trials", "author": "Jolliffe", "first-page": "276", "journal-title": "medRxiv", "key": "ref_19", "volume": "9", "year": "2020" }, { "DOI": "10.1016/j.dsx.2021.03.006", "article-title": "Impact of the vitamin D deficiency on COVID-19 infection and mortality in Asian countries", "author": "Jayawardena", "doi-asserted-by": "crossref", "first-page": "757", "journal-title": "Diabetes Metab. Syndr. Clin. Res. Rev.", "key": "ref_20", "volume": "15", "year": "2021" }, { "DOI": "10.1002/jmv.26832", "article-title": "Vitamin D deficiency is associated with COVID-19 positivity and severity of the disease", "author": "Demir", "doi-asserted-by": "crossref", "first-page": "2992", "journal-title": "J. Med. Virol.", "key": "ref_21", "volume": "93", "year": "2021" }, { "DOI": "10.1016/j.dsx.2020.04.050", "article-title": "Vitamin D concentrations and COVID-19 infection in UK Biobank", "author": "Hastie", "doi-asserted-by": "crossref", "first-page": "561", "journal-title": "Diabetes Metab. Syndr.", "key": "ref_22", "volume": "14", "year": "2020" }, { "DOI": "10.3390/nu15071581", "doi-asserted-by": "crossref", "key": "ref_23", "unstructured": "Basińska-Lewandowska, M., Lewandowski, K., Horzelski, W., Lewiński, A., and Skowrońska-Jóźwiak, E. (2023). Frequency of COVID-19 infection as a function of vitamin D levels. Nutrients, 15." }, { "DOI": "10.1101/2021.01.04.21249219", "doi-asserted-by": "crossref", "key": "ref_24", "unstructured": "Nikniaz, L., Akbarzadeh, M.A., Hosseinifard, H., and Hosseini, M. (2021). Vitamin D supplementation on mortality rate and clinical outcomes of COVID-19 patients: A systematic review and meta-analysis. medRxiv." }, { "DOI": "10.1186/s41043-023-00409-y", "article-title": "High-dose vitamin D supplementation is related to an improvement in serum alkaline phosphatase in COVID-19 patients; a randomized double-blinded clinical trial", "author": "Moghaddam", "doi-asserted-by": "crossref", "first-page": "71", "journal-title": "J. Health Popul. Nutr.", "key": "ref_25", "volume": "42", "year": "2023" }, { "DOI": "10.1007/s40520-020-01570-8", "article-title": "The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality", "author": "Ilie", "doi-asserted-by": "crossref", "first-page": "1195", "journal-title": "Aging Clin. Exp. Res.", "key": "ref_26", "volume": "32", "year": "2020" }, { "DOI": "10.1007/s00508-021-01833-y", "article-title": "Strong correlation between prevalence of severe vitamin D deficiency and population mortality rate from COVID-19 in Europe", "author": "Pugach", "doi-asserted-by": "crossref", "first-page": "403", "journal-title": "Wien. Klin. Wochenschr.", "key": "ref_27", "volume": "133", "year": "2021" }, { "DOI": "10.3934/mbe.2022417", "article-title": "Analyzing the relationship between the vitamin D deficiency and COVID-19 mortality rate and modeling the time-delay interactions between body’s immune healthy cells, infected cells, and virus particles with the effect of vitamin D levels", "author": "Pham", "doi-asserted-by": "crossref", "first-page": "8975", "journal-title": "Math. Biosci. Eng.", "key": "ref_28", "volume": "19", "year": "2022" }, { "DOI": "10.1038/s41597-020-00688-8", "article-title": "A cross-country database of COVID-19 testing", "author": "Hasell", "doi-asserted-by": "crossref", "first-page": "345", "journal-title": "Sci. Data", "key": "ref_29", "volume": "7", "year": "2020" }, { "key": "ref_30", "unstructured": "Our World in Data (2023, June 15). Explore the Global Situation: COVID-19 Data Explorer 2020–2022. Available online: https://ourworldindata.org/coronavirus#explore-the-global-situation." }, { "key": "ref_31", "unstructured": "Mathieu, E., Ritchie, H., Rodés-Guirao, L., Appel, C., Giattino, C., Hasell, J., Herre, B., Macdonald, B., Mathieu, E., and Mersmann, S. (2023, June 15). Coronavirus Pandemic (COVID-19): Our World Data. Available online: https://ourworldindata.org/coronavirus." }, { "DOI": "10.1007/s40520-020-01619-8", "article-title": "Revisiting the role of vitamin D levels in the prevention of COVID-19 infection and mortality in European countries post infections peak", "author": "Singh", "doi-asserted-by": "crossref", "first-page": "1609", "journal-title": "Aging Clin. Exp. Res.", "key": "ref_32", "volume": "32", "year": "2020" }, { "DOI": "10.1530/EJE-18-0736", "article-title": "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", "author": "Lips", "doi-asserted-by": "crossref", "first-page": "23", "journal-title": "Eur. J. Endocrinol.", "key": "ref_33", "volume": "180", "year": "2019" }, { "DOI": "10.1055/s-0030-1269854", "article-title": "Effect of vitamin D supplementation on testosterone levels in men", "author": "Pilz", "doi-asserted-by": "crossref", "first-page": "223", "journal-title": "Horm. Metab. Res.", "key": "ref_34", "volume": "43", "year": "2011" }, { "DOI": "10.1038/s41598-022-21513-9", "article-title": "Vitamin D status and severity of COVID-19", "author": "Nielsen", "doi-asserted-by": "crossref", "first-page": "19823", "journal-title": "Sci. Rep.", "key": "ref_35", "volume": "12", "year": "2022" }, { "DOI": "10.1016/j.nut.2020.111106", "article-title": "Increased risk for COVID-19 in patients with vitamin D deficiency", "author": "Katz", "doi-asserted-by": "crossref", "first-page": "111106", "journal-title": "Nutrition", "key": "ref_36", "volume": "84", "year": "2021" }, { "DOI": "10.1080/07435800.2020.1867162", "article-title": "Vitamin D status and COVID-19 clinical outcomes in hospitalized patients", "author": "Szeto", "doi-asserted-by": "crossref", "first-page": "66", "journal-title": "Endocr. Res.", "key": "ref_37", "volume": "46", "year": "2021" }, { "DOI": "10.1136/bmjopen-2021-059477", "article-title": "COVID-19 pandemic and vitamin D: Rising trends in status and in daily amounts of vitamin D provided by supplements", "author": "McKenna", "doi-asserted-by": "crossref", "first-page": "e059477", "journal-title": "BMJ Open", "key": "ref_38", "volume": "12", "year": "2022" }, { "DOI": "10.1080/10920277.2011.10597633", "article-title": "Jackknife Empirical likelihood intervals for Spearman’s rho", "author": "Wang", "doi-asserted-by": "crossref", "first-page": "475", "journal-title": "Am. Actuar. J.", "key": "ref_39", "volume": "15", "year": "2011" }, { "DOI": "10.1136/bmj.f3438", "article-title": "Statistics notes: Missing outcomes in randomised trials", "author": "Vickers", "doi-asserted-by": "crossref", "first-page": "f3438", "journal-title": "BMJ", "key": "ref_40", "volume": "346", "year": "2013" }, { "key": "ref_41", "unstructured": "R Core Team (2021). R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing. Available online: https://www.R-project.org/." }, { "DOI": "10.20944/preprints202003.0235.v2", "doi-asserted-by": "crossref", "key": "ref_42", "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": "10.3389/fimmu.2022.1023903", "article-title": "Vitamin D supplementation for the treatment of COVID-19: A systematic review and meta-analysis of randomized controlled trials", "author": "Krumbein", "doi-asserted-by": "crossref", "first-page": "1023903", "journal-title": "Front. Immunol.", "key": "ref_43", "volume": "13", "year": "2022" }, { "DOI": "10.1371/journal.pone.0267918", "doi-asserted-by": "crossref", "key": "ref_44", "unstructured": "Mariani, J., Antonietti, L., Tajer, C., Ferder, L., Inserra, F., Cunto, M.S., Brosio, D., Ross, F., Zylberman, M., and López, D.E. (2022). High-dose vitamin D versus placebo to prevent complications in COVID-19 patients: Multicentre randomized controlled clinical trial. PLoS ONE, 17." }, { "DOI": "10.1080/10408398.2020.1841090", "article-title": "Vitamin D deficiency aggravates COVID-19: Systematic review and meta-analysis", "author": "Pereira", "doi-asserted-by": "crossref", "first-page": "1308", "journal-title": "Crit. Rev. Food Sci. Nutr.", "key": "ref_45", "volume": "62", "year": "2020" }, { "DOI": "10.1080/14787210.2022.2035217", "article-title": "COVID-19 andvitamin D (Co-VIVID study): A systematic review and meta-analysis of randomized controlled trials", "author": "Varikasuvu", "doi-asserted-by": "crossref", "first-page": "907", "journal-title": "Expert Rev. Anti Infect. Ther.", "key": "ref_46", "volume": "20", "year": "2022" }, { "DOI": "10.3390/nu12092757", "doi-asserted-by": "crossref", "key": "ref_47", "unstructured": "Radujkovic, A., and Merle, U. (2020). Reply to: Vitamin D Insufficiency May Account for Almost Nine of Ten COVID-19 Deaths: Time to Act. Comment on: Vitamin D Deficiency and Outcome of COVID-19 Patients. Nutrients, 12." }, { "DOI": "10.1017/S0029665122002798", "article-title": "Vitamin D in the prevention or treatment of COVID-19", "author": "Martineau", "doi-asserted-by": "crossref", "first-page": "200", "journal-title": "Proc. Nutr. Soc.", "key": "ref_48", "volume": "82", "year": "2023" }, { "DOI": "10.1007/s40618-020-01276-8", "article-title": "COVID-19 and the endocrine system: Exploring the unexplored", "author": "Pal", "doi-asserted-by": "crossref", "first-page": "1027", "journal-title": "J. Endocrinol. Investig.", "key": "ref_49", "volume": "43", "year": "2020" }, { "DOI": "10.3390/nu13030717", "doi-asserted-by": "crossref", "key": "ref_50", "unstructured": "Sulli, A., Gotelli, E., Casabella, A., Paolino, S., Pizzorni, C., Alessandri, E., Grosso, M., Ferone, D., Smith, V., and Cutolo, M. (2021). Vitamin D and lung outcomes in elderly COVID-19 patients. Nutrients, 13." }, { "DOI": "10.3390/nu12113377", "doi-asserted-by": "crossref", "key": "ref_51", "unstructured": "Annweiler, G., Corvaisier, M., Gautier, J., Dubée, V., Legrand, E., Sacco, G., and Annweiler, C. (2020). Vitamin D supplementation associated to better survival in hospitalized frail elderly COVID-19 patients: The GERIA-COVID quasi-experimental study. Nutrients, 12." }, { "DOI": "10.1007/s40520-020-01716-8", "article-title": "Vitamin D status and COVID-19 in older adults", "author": "Mandal", "doi-asserted-by": "crossref", "first-page": "2425", "journal-title": "Aging Clin. Exp. Res.", "key": "ref_52", "volume": "32", "year": "2020" }, { "DOI": "10.1164/rccm.202006-2405OC", "article-title": "Case fatality rates for patients with COVID-19 requiring invasive mechanical ventilation. a meta-analysis", "author": "Lim", "doi-asserted-by": "crossref", "first-page": "54", "journal-title": "Am. J. Respir. Crit. Care Med.", "key": "ref_53", "volume": "203", "year": "2021" }, { "DOI": "10.1186/s40001-016-0208-y", "article-title": "Vitamin D and airway infections: A European perspective", "author": "Zittermann", "doi-asserted-by": "crossref", "first-page": "14", "journal-title": "Eur. J. Med. Res.", "key": "ref_54", "volume": "21", "year": "2016" }, { "DOI": "10.4161/derm.20731", "article-title": "Influence of drugs on vitamin D and calcium metabolism", "author": "Kisters", "doi-asserted-by": "crossref", "first-page": "158", "journal-title": "Derm. Endocrinol.", "key": "ref_55", "volume": "4", "year": "2012" }, { "DOI": "10.1111/nbu.12430", "article-title": "Is a vitamin D fortification strategy needed?", "author": "Buttriss", "doi-asserted-by": "crossref", "first-page": "115", "journal-title": "Nutr. Bull.", "key": "ref_56", "volume": "45", "year": "2020" }, { "DOI": "10.3945/ajcn.116.151415", "article-title": "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", "author": "Itkonen", "doi-asserted-by": "crossref", "first-page": "1512", "journal-title": "Am. J. Clin. Nutr.", "key": "ref_57", "volume": "105", "year": "2017" }, { "key": "ref_58", "unstructured": "National Institute for Health and Care Excellence (NICE) (2023, June 15). COVID-19 Rapid Guideline: Vitamin D 2022. Available online: https://www.nice.org.uk/guidance/ng187." }, { "DOI": "10.1111/nbu.12108", "article-title": "Vitamin D: An overview of vitamin D status and intake in Europe", "author": "Spiro", "doi-asserted-by": "crossref", "first-page": "322", "journal-title": "Nutr. Bull.", "key": "ref_59", "volume": "9", "year": "2014" }, { "DOI": "10.1001/jamanetworkopen.2020.19722", "article-title": "Association of vitamin D status and other clinical characteristics with COVID-19 test results", "author": "Meltzer", "doi-asserted-by": "crossref", "first-page": "e2019722", "journal-title": "JAMA Netw. Open.", "key": "ref_60", "volume": "3", "year": "2020" }, { "DOI": "10.1016/j.fct.2022.112901", "article-title": "The prognostic role of micronutrient status and supplements in COVID-19 outcomes: A systematic review", "author": "Pechlivanidou", "doi-asserted-by": "crossref", "first-page": "112901", "journal-title": "Food Chem. Toxicol.", "key": "ref_61", "volume": "162", "year": "2022" }, { "DOI": "10.3389/fpubh.2022.993662", "article-title": "Comorbidities, sociodemographic factors, and determinants of health on COVID-19 fatalities in the United States", "author": "Gerken", "doi-asserted-by": "crossref", "first-page": "993662", "journal-title": "Front. Public Health", "key": "ref_62", "volume": "10", "year": "2022" }, { "DOI": "10.1371/journal.pone.0018625", "doi-asserted-by": "crossref", "key": "ref_63", "unstructured": "Fang, F., Kasperzyk, J.L., Shui, I., Hendrickson, W., Hollis, B.W., Fall, K., Ma, J., Gaziano, J.M., Stampfer, M.J., and Mucci, L.A. (2011). Prediagnostic plasma vitamin D metabolites and mortality among patients with prostate cancer. PLoS ONE, 6." }, { "key": "ref_64", "unstructured": "National Health Service Laboratory (2023, June 15). Direct Public Vitamin D Testing from our NHS Laboratory in West Bromwich 2022. Available online: https://www.vitamindtest.org.uk/." }, { "DOI": "10.1007/s12603-020-1479-0", "article-title": "Impact of Serum 25(OH) Vitamin D Level on Mortality in Patients with COVID-19 in Turkey", "author": "Karahan", "doi-asserted-by": "crossref", "first-page": "189", "journal-title": "J. Nutr. Health Aging", "key": "ref_65", "volume": "25", "year": "2021" }, { "DOI": "10.1371/journal.pone.0239799", "doi-asserted-by": "crossref", "key": "ref_66", "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": "10.1093/jn/136.4.1130", "article-title": "Strategies to improve vitamin D status in northern European children: Exploring the merits of vitamin D fortification and supplementation", "author": "Tylavsky", "doi-asserted-by": "crossref", "first-page": "1130", "journal-title": "J. Nutr.", "key": "ref_67", "volume": "136", "year": "2006" }, { "key": "ref_68", "unstructured": "Public Health England (2023, June 15). COVID-19: Understanding the Impact on BAME Communities 2020, Available online: https://www.gov.uk/government/publications/covid-19-understanding-the-impact-on-bame-communities." }, { "DOI": "10.1111/cen.14276", "article-title": "Low serum 25-hydroxyvitamin D (25[OH]D) levels in patients hospitalized with COVID-19 are associated with greater disease severity", "author": "Panagiotou", "doi-asserted-by": "crossref", "first-page": "508", "journal-title": "Clin. Endocrinol.", "key": "ref_69", "volume": "93", "year": "2020" } ], "reference-count": 69, "references-count": 69, "relation": {}, "resource": { "primary": { "URL": "https://www.mdpi.com/2072-6643/15/22/4818" } }, "score": 1, "short-title": [], "source": "Crossref", "subject": [ "Food Science", "Nutrition and Dietetics" ], "subtitle": [], "title": "Association between Average Vitamin D Levels and COVID-19 Mortality in 19 European Countries—A Population-Based Study", "type": "journal-article", "volume": "15" }