{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T14:21:00Z","timestamp":1787062860197,"version":"build-2736575974"},"reference-count":43,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2022,11,17]],"date-time":"2022-11-17T00:00:00Z","timestamp":1668643200000},"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>The aim of this study was to investigate changes in 25(OH)D (25-hydroxyvitamin D) levels and in the vitamin D status of Korean adults before and during the coronavirus disease (COVID-19) pandemic. This study compared serum 25(OH)D levels before and after the pandemic in 1483 adults aged 19 years and older who were screened at a university hospital. Subjects were selected only from participants tested in the same season before and after the pandemic. The pre-COVID-19 testing period was from 1 March 2018 to 31 November 2019; the testing period in the COVID-19 era was from 1 June 2020 to 31 November 2021. The mean 25(OH)D level for all participants was 21.4 \u00b1 10.2 ng\/mL prior to the outbreak of COVID-19, which increased to 23.6 \u00b1 11.8 ng\/mL during the COVID-19 lockdown period (p &lt; 0.001). The increase was particularly dramatic in elderly females (28.8 \u00b1 12.3 ng\/mL to 37.7 \u00b1 18.6 ng\/mL, p = 0.008). The prevalence of vitamin D deficiency decreased in both males (48.4% to 44.5%, p = 0.005) and females (57.0% to 46.0%, p &lt; 0.001). In conclusion, 25(OH)D levels in Korean adults increased during the COVID-19 era, and the prevalence of vitamin D deficiency decreased accordingly.<\/jats:p>","DOI":"10.3390\/nu14224863","type":"journal-article","created":{"date-parts":[[2022,11,18]],"date-time":"2022-11-18T04:08:40Z","timestamp":1668744520000},"page":"4863","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Changes in Vitamin D Status in Korean Adults during the COVID-19 Pandemic"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6324-0923","authenticated-orcid":false,"given":"Ji-Young","family":"Kwon","sequence":"first","affiliation":[{"name":"Department of Family Medicine, St. Vincent\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 16247, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4627-291X","authenticated-orcid":false,"given":"Sung-Goo","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Family Medicine, St. Vincent\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 16247, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,17]]},"reference":[{"key":"ref_1","unstructured":"(2021, September 21). World Health Organization: Coronavirus Disease (COVID-19) Pandemic. Available online: https:\/\/www.who.int\/emergencies\/diseases\/novel-coronavirus-2019."},{"key":"ref_2","unstructured":"Ministry of Health and Welfare of South Korea (2022, September 21). Coronavirus Disease-19, Republic of Korea, Available online: http:\/\/ncov.mohw.go.kr\/en\/."},{"key":"ref_3","unstructured":"(2022, September 21). Coronavirus Infectious Disease-19 Press Release: From May 2nd (Mon), the Mandatory Wearing of an Outdoor Mask Has Been Adjusted. Available online: http:\/\/ncov.mohw.go.kr\/tcmBoardView.do?contSeq=371325."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Meoli, M., Muggli, F., Lava, S.A.G., Bianchetti, M.G., Agostoni, C., Kocher, C., B\u00fchrer, T.W., Ciliberti, L., Simonetti, G.D., and Milani, G.P. (2021). Vitamin D Status in Adolescents during COVID-19 Pandemic: A Cross-Sectional Comparative Study. Nutrients, 13.","DOI":"10.3390\/nu13051467"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1788","DOI":"10.1002\/oby.22935","article-title":"Collateral Damage of the COVID-19 Pandemic on Nutritional Quality and Physical Activity: Perspective from South Korea","volume":"28","author":"Lim","year":"2020","journal-title":"Obesity"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1038\/s41430-020-0634-3","article-title":"Nutrition amid the COVID-19 pandemic: A multi-level framework for action","volume":"74","author":"Naja","year":"2020","journal-title":"Eur. J. Clin. Nutr."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"188","DOI":"10.4274\/jcrpe.galenos.2022.2021-10-6","article-title":"How Vitamin D Levels of Children Changed During COVID-19 Pandemic: A Comparison of Pre-pandemic and Pandemic Periods","volume":"14","author":"Yurtseven","year":"2022","journal-title":"J. Clin. Res. Pediatr. Endocrinol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e21","DOI":"10.3346\/jkms.2021.36.e21","article-title":"The Impact of the Coronavirus Disease-2019 Pandemic on Childhood Obesity and Vitamin D Status","volume":"36","author":"Kang","year":"2021","journal-title":"J. Korean Med. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"278","DOI":"10.1093\/eurpub\/ckab004","article-title":"Is COVID-19 lockdown associated with vitamin D deficiency?","volume":"31","author":"Lippi","year":"2021","journal-title":"Eur. J. Public Health"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Ferrari, D., Locatelli, M., Faraldi, M., and Lombardi, G. (2021). Changes in 25-(OH) Vitamin D Levels during the SARS-CoV-2 Outbreak: Lockdown-Related Effects and First-to-Second Wave Difference\u2014An Observational Study from Northern Italy. Biology, 10.","DOI":"10.3390\/biology10030237"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Raposo, L., Martins, S., Ferreira, D., Guimar\u00e3es, J.T., and Santos, A.C. (2017). Vitamin D, parathyroid hormone and metabolic syndrome\u2014The PORMETS study. BMC Endocr. Disord., 17.","DOI":"10.1186\/s12902-017-0221-3"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e11032","DOI":"10.1097\/MD.0000000000011032","article-title":"Vitamin D status in South Korean population: Seven-year trend from the KNHANES","volume":"97","author":"Park","year":"2018","journal-title":"Medicine"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"70","DOI":"10.3343\/lmo.2016.6.2.70","article-title":"Prevalence of Vitamin D Deficiency and Insufficiency in Korean Children and Adolescents and Associated Factors","volume":"6","author":"Anna","year":"2016","journal-title":"Lab. Med. Online"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"800","DOI":"10.1007\/s12020-015-0548-3","article-title":"Seasonal variations in serum 25-hydroxy vitamin D levels in a Swedish cohort","volume":"49","author":"Klingberg","year":"2015","journal-title":"Endocrine"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2502","DOI":"10.3390\/nu5072502","article-title":"Vitamin D and Immune Function","volume":"5","author":"Prietl","year":"2013","journal-title":"Nutrients"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1308","DOI":"10.1080\/10408398.2020.1841090","article-title":"Vitamin D deficiency aggravates COVID-19: Systematic review and meta-analysis","volume":"62","author":"Pereira","year":"2022","journal-title":"Crit. Rev. Food Sci. Nutr."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Bleakley, A.S., Licciardi, P.V., and Binks, M.J. (2021). Vitamin D Modulation of the Innate Immune Response to Paediatric Respiratory Pathogens Associated with Acute Lower Respiratory Infections. Nutrients, 13.","DOI":"10.3390\/nu13010276"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1111\/j.1399-5448.2012.00890.x","article-title":"Serum vitamin D levels are lower in Australian children and adolescents with type 1 diabetes than in children without diabetes","volume":"14","author":"Greer","year":"2013","journal-title":"Pediatr Diabetes"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"329","DOI":"10.4162\/nrp.2021.15.3.329","article-title":"Serum vitamin D status and metabolic syndrome: A systematic review and dose-response meta-analysis","volume":"15","author":"Lee","year":"2021","journal-title":"Nutr. Res. Pract."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Melguizo-Rodriguez, L., Costela-Ruiz, V.J., Garcia-Recio, E., De Luna-Bertos, E., Ruiz, C., and Illescas-Montes, R. (2021). Role of Vitamin D in the Metabolic Syndrome. Nutrients, 13.","DOI":"10.3390\/nu13030830"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1586\/17476348.2016.1128326","article-title":"The impact of vitamin D on asthmatic human airway smooth muscle","volume":"10","author":"Hall","year":"2016","journal-title":"Expert Rev. Respir. Med."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"65","DOI":"10.5415\/apallergy.2017.7.2.65","article-title":"The role of vitamin D in allergic rhinitis","volume":"7","author":"Tian","year":"2017","journal-title":"Asia Pac. Allergy"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1016\/j.nut.2016.01.023","article-title":"Vitamin D and atopic dermatitis: A systematic review and meta-analysis","volume":"32","author":"Kim","year":"2016","journal-title":"Nutrition"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1002\/cbf.3597","article-title":"Is there a link between vitamin D status, SARS-CoV-2 infection risk and COVID-19 severity?","volume":"39","author":"Ferrari","year":"2021","journal-title":"Cell Biochem. Funct."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Mercola, J., Grant, W.B., and Wagner, C.L. (2020). Evidence Regarding Vitamin D and Risk of COVID-19 and Its Severity. Nutrients, 12.","DOI":"10.3390\/nu12113361"},{"key":"ref_26","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_27","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1007\/s00223-019-00559-4","article-title":"Vitamin D Deficiency: Defining, Prevalence, Causes, and Strategies of Addressing","volume":"106","author":"Cashman","year":"2020","journal-title":"Calcif. Tissue Int."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"N. Engl. J. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1210\/jc.2010-2133","article-title":"Vitamin D insufficiency in Korea\u2014A greater threat to younger generation: The Korea National Health and Nutrition Examination Survey (KNHANES) 2008","volume":"96","author":"Choi","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_30","unstructured":"(2022, October 03). Korea Meteorological Agency Meteorological Annual Report: Sunshine Time Trend. Available online: https:\/\/www.index.go.kr\/potal\/main\/EachDtlPageDetail.do?idx_cd=1402."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"7000","DOI":"10.1038\/ncomms8000","article-title":"Widespread seasonal gene expression reveals annual differences in human immunity and physiology","volume":"6","author":"Dopico","year":"2015","journal-title":"Nat Commun"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1097\/01.NAJ.0000721884.47230.b1","article-title":"Do Low Vitamin D Levels Increase COVID-19 Risk?","volume":"120","author":"Pfeifer","year":"2020","journal-title":"Am. J. Nurs."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"i6583","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","volume":"356","author":"Martineau","year":"2017","journal-title":"BMJ"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.jgar.2020.05.006","article-title":"Vitamin D deficiency and the COVID-19 pandemic","volume":"22","author":"Zemb","year":"2020","journal-title":"J. Glob. Antimicrob. Resist."},{"key":"ref_35","unstructured":"(2022, October 03). BBC News: Covid and Vitamin D: \u2018Not Enough Evidence\u2019 for Treatment. Available online: https:\/\/www.bbc.com\/news\/health-55333063."},{"key":"ref_36","unstructured":"(2022, October 03). BBC News: Covid: Free Vitamin D Pills for 2.5 Million Vulnerable in England. Available online: https:\/\/www.bbc.com\/news\/health-55108613."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Pu\u015bcion-Jakubik, A., Bielecka, J., Grabia, M., Mielech, A., Markiewicz-\u017bukowska, R., Mielcarek, K., Moskwa, J., Naliwajko, S.K., Soroczy\u0144ska, J., and Gromkowska-K\u0119pka, K.J. (2021). Consumption of Food Supplements during the Three COVID-19 Waves in Poland-Focus on Zinc and Vitamin D. Nutrients, 13.","DOI":"10.3390\/nu13103361"},{"key":"ref_38","unstructured":"(2022, October 03). Edaily: Corona Consumption Market Continued This Year\u2026 Milk Kit and Healthy Food Smile. Available online: https:\/\/www.edaily.co.kr\/news\/read?newsId=02355046629279504&mediaCodeNo=257&OutLnkChk=Y."},{"key":"ref_39","unstructured":"(2022, October 03). iHerb Meeting Increased Worldwide Demand for Vitamin D and C. Available online: https:\/\/siswa.blog\/f-https-www.iherb.com\/pressreleases\/increasd-demand-for-vitamins\/1098."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Milani, G.P., Macchi, M., and Guz-Mark, A. (2021). Vitamin C in the Treatment of COVID-19. Nutrients, 13.","DOI":"10.3390\/nu13041172"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1024\/0300-9831\/a000694","article-title":"Dietary supplements, vitamins and minerals as potential interventions against viruses: Perspectives for COVID-19","volume":"92","author":"Islam","year":"2022","journal-title":"Int. J. Vitam. Nutr. Res."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1373","DOI":"10.1111\/all.15136","article-title":"Nutrient supplementation for prevention of viral respiratory tract infections in healthy subjects: A systematic review and meta-analysis","volume":"77","author":"Meyer","year":"2022","journal-title":"Allergy"},{"key":"ref_43","unstructured":"(2022, October 03). Korea Ministry of Culture, Sports and Tourism 2020 National Life Sports Survey. Available online: https:\/\/www.mcst.go.kr\/kor\/s_policy\/dept\/deptView.jsp?pCurrentPage=3&pType=07&pTab=01&pSeq=1442&pDataCD=0417000000&pSearchType=01&pSearchWord=."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/14\/22\/4863\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:20:07Z","timestamp":1760145607000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/14\/22\/4863"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,11,17]]},"references-count":43,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["nu14224863"],"URL":"https:\/\/doi.org\/10.3390\/nu14224863","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,11,17]]}}}