The Impact of Vitamin D Level on the Severity and Outcome of Hospitalized Patients with COVID-19 Disease
Dania Alkhafaji, Reem Al Argan, Waleed Albaker, Abdulmohsen Al Elq, Mohammed Al-Hariri, Abir Alsaid, Abrar Alwaheed, Safi Alqatari, Alaa Alzaki, Sara Alwarthan, Fatima Alrubaish, Haya Alguaimi, Fatema Ismaeel, Nidaa Alsaeed, Zainab Alelq, Fatma Zainuddin
International Journal of General Medicine, doi:10.2147/ijgm.s346169
The world is experiencing a life-altering and extraordinary situation in response to the COVID-19 pandemic. There are limited data and controversies regarding the relationship between vitamin D (Vit D) status and COVID-19 disease. Thus, this study was designed to investigate the association between Vit D levels and the severity or outcomes of COVID-19 disease. Methods: A cross-sectional observational study was conducted in the Eastern province of Saudi Arabia from January to August 2021. All the admitted patients who were diagnosed with COVID-19 infection were distributed into three groups depending on their Vit D levels: normal, insufficiency, and deficiency. For the three groups, demographic data, and laboratory investigations as well as data regarding the severity of COVID-19 were collected and analysed. Results: A total of 203 diagnosed cases of COVID-19 were included in this study. The Vit D level was normal (>30) in 31 (15.3%) cases, insufficient in 45 (22.2%) cases and deficient in 127 (62.6%) cases. Among the included cases, 58 (28.6%) were critical cases, 109 (53.7%) were severe and 36 (17.7%) had a mild-moderate COVID-19 infection. The most prevalent comorbidity of patients was diabetes mellitus 117 (57.6%), followed by hypertension 70 (34.5%), cardiac disease 24 (11.8%), chronic kidney disease 19 (9.4%) and chronic respiratory disease in 17 (8.4%) cases. Importantly, the current study did not detect any significant association between Vit D status and COVID-19 severity (p-value=0.371) or outcomes (hospital stay, intensive care units admission, ventilation, and mortality rate) (p-value > 0.05), even after adjusting the statistical model for the confounders.
Conclusion: In hospital settings, Vit D levels are not associated with the severity or outcomes of COVID-19 disease. Further, well-designed studies are required to determine whether Vit D status provides protective effects against worse COVID-19 outcomes.
Author Contributions All authors made a significant contribution to the work reported, whether in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure The authors report no conflicts of interest in this work.
International Journal of General Medicine
Dovepress
References
Al-Alyani, Ha, On, Alani, Sadat-Ali, Vitamin D deficiency in Saudi Arabians: a reality or simply hype: a meta-analysis (2008-2015), J Family Community Med,
doi:10.4103/jfcm.JFCM_73_17Al-Harbi, Ya, Abdellatif, Al-Ahmadey, Alahmadi, Retrospective evaluation of the serum level of vitamin D among COVID-19 patients in Al Madinah, Saudi Arabia, Biotechnol Biochem Res,
doi:10.30918/BBR.91.21.018Al-Raddadi, Bahijri, Borai, Alraddadi, Prevalence of lifestyle practices that might affect bone health in relation to vitamin D status among female Saudi adolescents, Nutrition,
doi:10.1016/J.NUT.2017.07.015Alahmari, Khan, Elganainy, Epidemiological and clinical features of COVID-19 patients in Saudi Arabia, J Infect Public Health,
doi:10.1016/j.jiph.2021.01.003Alguwaihes, Sabico, Hasanato, Severe vitamin D deficiency is not related to SARS-CoV-2 infection but may increase mortality risk in hospitalized adults: a retrospective casecontrol study in an Arab Gulf country, Aging Clin Exp Res,
doi:10.1007/S40520-021-01831-0Ali, Elevated level of C-reactive protein may be an early marker to predict risk for severity of COVID-19, J Med Virol,
doi:10.1002/JMV.26097Ali, Noman, Guo, Myoglobin and C-reactive protein are efficient and reliable early predictors of COVID-19 associated mortality, Sci Rep,
doi:10.1038/S41598-021-85426-9Aljohani, Os, Dairy products consumption and serum 25-hydroxyvitamin D level in Saudi children and adults, Int J Clin Exp Pathol
Alkerwi, Sauvageot, Gilson, Stranges, Prevalence and correlates of vitamin D deficiency and insufficiency in Luxembourg adults: evidence from the observation of cardiovascular risk factors (ORISCAV-LUX) study, Nutrients,
doi:10.3390/nu7085308Alyami, Naser, Orabi, Alwafi, Alyami, Epidemiology of COVID-19 in the Kingdom of Saudi Arabia: an ecological study, Front Public Health,
doi:10.3389/fpubh.2020.00506Alzaheb, Al-Amer, Prevalence and predictors of hypovitaminosis D among female university students in Tabuk, Saudi Arabia, Clin Med Insights Womens Health,
doi:10.1177/1179562X17702391Alzaheb, The prevalence of hypovitaminosis D and its associated risk factors among women of reproductive age in Saudi Arabia: a systematic review and meta-analysis, Clin Med Insights Womens Health,
doi:10.1177/1179562x18767884Butler-Laporte, Nakanishi, Mooser, Vitamin D and COVID-19 susceptibility and severity in the COVID-19 host genetics initiative: a Mendelian randomization study, PLoS Med,
doi:10.1371/journal.pmed.1003605Carpagnano, Lecce, Quaranta, Vitamin D deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to COVID-19, J Endocrinol Invest,
doi:10.1007/s40618-020-01370-xCastillo, Costa, Barrios, Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: a pilot randomized clinical study, J Steroid Biochem Mol Biol,
doi:10.1016/j.jsbmb.2020.105751Darling, Ahmadi, Ward, Vitamin D concentration, body mass index, ethnicity and SARS-CoV-2/COVID-19: initial analysis of the first-reported UK Biobank Cohort positive cases (n 1474) compared with negative controls (n 4643), Proc Nutr Soc,
doi:10.1017/S0029665121000185Gibson-Moore, Vitamin D: what's new a year on from the COVID-19 outbreak?, Nutr Bull,
doi:10.1111/nbu.12499Grant, Lahore, Mcdonnell, Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths, Nutrients,
doi:10.3390/NU12040988Hammad, Benajiba, Lifestyle factors influencing bone health in young adult women in Saudi Arabia, Afr Health Sci,
doi:10.4314/AHS.V17I2.28Hastie, Mackay, Ho, Vitamin D concentrations and COVID-19 infection in UK Biobank, Diabetes Metab Syndr Clin Res Rev,
doi:10.1016/j.dsx.2020.04.050Holick, Binkley, Bischoff-Ferrari, Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline, J Clin Endocrinol Metab,
doi:10.1210/JC.2011-0385Honardoost, Ghavideldarestani, Khamseh, Role of vitamin D in pathogenesis and severity of COVID-19 infection, Arch Physiol Biochem,
doi:10.1080/13813455.2020.1792505Itkonen, Erkkola, Cje, Vitamin D fortification of fluid milk products and their contribution to vitamin D intake and vitamin D status in observational studies-a review, Nutrients,
doi:10.3390/nu10081054Jain, Chaurasia, Sengar, Singh, Mahor et al., Analysis of vitamin D level among asymptomatic and critically ill COVID-19 patients and its correlation with inflammatory markers, Sci Rep,
doi:10.1038/s41598-020-77093-zJolliffe, Stefanidis, Wang, Vitamin d metabolism is dysregulated in asthma and chronic obstructive pulmonary disease, Am J Respir Crit Care Med,
doi:10.1164/rccm.201909-1867OCKanan, Saleh, Fakhoury, Adham, Aljaser et al., Year-round vitamin D deficiency among Saudi female out-patients, Public Health Nutr,
doi:10.1017/S1368980012002947Kruit, Zanen, The association between vitamin D and C-reactive protein levels in patients with inflammatory and non-inflammatory diseases, Clin Biochem,
doi:10.1016/J.CLINBIOCHEM.2016.01.002Lu, Chen, Zhang, An evaluation of the vitamin D3 content in fish: is the vitamin D content adequate to satisfy the dietary requirement for vitamin D?, J Steroid Biochem Mol Biol,
doi:10.1016/J.JSBMB.2006.12.010Mansur, Tajer, Mariani, Inserra, Ferder et al., Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection, Clin e Investig En Arterioscler,
doi:10.1016/j.arteri.2020.05.003Mckee, Stuckler, If the world fails to protect the economy, COVID-19 will damage health not just now but also in the future, Nat Med,
doi:10.1038/s41591-020-0863-yMercola, Grant, Wagner, Evidence regarding vitamin d and risk of covid-19 and its severity, Nutrients,
doi:10.3390/nu12113361Murai, Fernandes, Sales, Effect of a single high dose of vitamin D3 on hospital length of stay in patients with moderate to severe COVID-19: a randomized clinical trial, JAMA,
doi:10.1001/jama.2020.26848Murai, Fernandes, Sales, Effect of vitamin D3 supplementation vs placebo on hospital length of stay in patients with severe COVID-19: a multicenter, double-blind, randomized controlled trial, medRxiv,
doi:10.1001/jama.2020.26848Panfili, Roversi, Argenio, Rossi, Cappa et al., Possible role of vitamin D in Covid-19 infection in pediatric population, J Endocrinol Invest,
doi:10.1007/s40618-020-01327-0Rabenberg, Scheidt-Nave, Busch, Rieckmann, Hintzpeter et al., Vitamin D status among adults in Germany -results from the German Health Interview and Examination Survey for Adults (DEGS1) chronic disease epidemiology, International Journal of General Medicine,
doi:10.1186/s12889-015-2016-7Smet, Smet, Herroelen, Gryspeerdt, Martens, Serum 25(OH)D level on hospital admission associated with COVID-19 stage and mortality, Am J Clin Pathol,
doi:10.1093/AJCP/AQAA252Teymoori-Rad, Shokri, Salimi, Marashi, The interplay between vitamin D and viral infections, Rev Med Virol,
doi:10.1002/RMV.2032Zareef, Jackson, Alkahtani, Vitamin D intake among premenopausal women living in Jeddah: food sources and relationship to demographic factors and bone health, J Nutr Metab,
doi:10.1155/2018/8570986DOI record:
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"DOI": "10.3390/nu7085308",
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"doi-asserted-by": "publisher",
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"DOI": "10.1080/10408390500466174",
"author": "Palacios",
"doi-asserted-by": "publisher",
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"journal-title": "Crit Rev Food Sci Nutr",
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"journal-title": "Nutrition",
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{
"DOI": "10.1038/s41591-020-0863-y",
"author": "McKee",
"doi-asserted-by": "publisher",
"first-page": "640",
"journal-title": "Nat Med",
"key": "ref15",
"volume": "26",
"year": "2020"
},
{
"key": "ref16",
"unstructured": "World Health Organization. Available from: https://covid19.who.int/region/emro/country/sa. Accessed December 29, 2021."
},
{
"DOI": "10.1016/j.arteri.2020.05.003",
"author": "Mansur",
"doi-asserted-by": "publisher",
"first-page": "267",
"journal-title": "Clin e Investig En Arterioscler",
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"volume": "32",
"year": "2020"
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{
"DOI": "10.3390/NU12040988",
"author": "Grant",
"doi-asserted-by": "publisher",
"first-page": "988",
"journal-title": "Nutrients",
"key": "ref18",
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"author": "Hastie",
"doi-asserted-by": "publisher",
"first-page": "561",
"journal-title": "Diabetes Metab Syndr Clin Res Rev",
"key": "ref21",
"volume": "14",
"year": "2020"
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"DOI": "10.1017/S0029665121000185",
"author": "Darling",
"doi-asserted-by": "publisher",
"first-page": "7",
"journal-title": "Proc Nutr Soc",
"key": "ref22",
"volume": "80",
"year": "2021"
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"DOI": "10.1016/J.JIPH.2020.06.021",
"author": "Ali",
"doi-asserted-by": "publisher",
"first-page": "1373",
"journal-title": "J Infect Public Health",
"key": "ref23",
"volume": "13",
"year": "2020"
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{
"DOI": "10.1371/journal.pmed.1003605",
"author": "Butler-Laporte",
"doi-asserted-by": "publisher",
"first-page": "e1003605",
"journal-title": "PLoS Med",
"key": "ref24",
"volume": "18",
"year": "2021"
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"DOI": "10.1007/s40618-020-01327-0",
"author": "Panfili",
"doi-asserted-by": "publisher",
"first-page": "1",
"journal-title": "J Endocrinol Invest",
"key": "ref25",
"volume": "15",
"year": "2021"
},
{
"DOI": "10.1080/13813455.2020.1792505",
"author": "Honardoost",
"doi-asserted-by": "publisher",
"first-page": "1",
"journal-title": "Arch Physiol Biochem",
"key": "ref26",
"volume": "30",
"year": "2020"
},
{
"DOI": "10.1016/j.jsbmb.2020.105751",
"author": "Entrenas Castillo",
"doi-asserted-by": "publisher",
"first-page": "105751",
"journal-title": "J Steroid Biochem Mol Biol",
"key": "ref27",
"volume": "203",
"year": "2020"
},
{
"DOI": "10.1001/jama.2020.26848",
"author": "Murai",
"doi-asserted-by": "publisher",
"first-page": "1053",
"journal-title": "JAMA",
"key": "ref28",
"volume": "325",
"year": "2021"
},
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"key": "ref29",
"unstructured": "Public Health Authority. Laboratory diagnosis. Available from: https://covid19.cdc.gov.sa/professionals-health-workers/laboratory-diagnosis/. Accessed December 9, 2021."
},
{
"DOI": "10.1210/JC.2011-0385",
"author": "Holick",
"doi-asserted-by": "publisher",
"first-page": "1911",
"journal-title": "J Clin Endocrinol Metab",
"key": "ref30",
"volume": "96",
"year": "2011"
},
{
"DOI": "10.1007/s00394-020-02372-4",
"author": "Hastie",
"doi-asserted-by": "publisher",
"first-page": "545",
"journal-title": "Eur J Nutr",
"key": "ref31",
"volume": "60",
"year": "2021"
},
{
"DOI": "10.1001/jama.2020.26848",
"author": "Murai",
"doi-asserted-by": "publisher",
"journal-title": "medRxiv",
"key": "ref32",
"year": "2020"
},
{
"DOI": "10.4103/jfcm.JFCM_73_17",
"author": "Al-Alyani",
"doi-asserted-by": "publisher",
"first-page": "1",
"journal-title": "J Family Community Med",
"key": "ref33",
"volume": "25",
"year": "2018"
},
{
"DOI": "10.3389/fpubh.2020.00506",
"author": "Alyami",
"doi-asserted-by": "publisher",
"first-page": "506",
"journal-title": "Front Public Health",
"key": "ref34",
"volume": "8",
"year": "2020"
},
{
"DOI": "10.1016/j.jiph.2021.01.003",
"author": "Alahmari",
"doi-asserted-by": "publisher",
"first-page": "437",
"journal-title": "J Infect Public Health",
"key": "ref35",
"volume": "14",
"year": "2021"
},
{
"DOI": "10.1007/S40520-021-01831-0",
"author": "Alguwaihes",
"doi-asserted-by": "publisher",
"first-page": "1415",
"journal-title": "Aging Clin Exp Res",
"key": "ref36",
"volume": "33",
"year": "2021"
},
{
"DOI": "10.1038/s41598-020-77093-z",
"author": "Jain",
"doi-asserted-by": "publisher",
"first-page": "1",
"journal-title": "Sci Rep",
"key": "ref37",
"volume": "10",
"year": "2020"
},
{
"DOI": "10.30918/BBR.91.21.018",
"author": "Al-Harbi",
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