{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T13:31:15Z","timestamp":1780320675686,"version":"3.54.1"},"reference-count":35,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,6,11]],"date-time":"2021-06-11T00:00:00Z","timestamp":1623369600000},"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>We aimed to investigate the changes in vitamin D levels and factors associated with vitamin D deficiency (VDD) during the first year of life in Korean preterm infants. We enrolled 333 preterm infants who were born at Kyungpook National University Children\u2019s Hospital between March 2013 and December 2019. 25-hydroxyvitamin D (25-OHD) levels and medical records were collected at birth, 6 months, and 12 months of age. The mean gestational age was 33.4 \u00b1 2.3 weeks and mean 25-OHD levels at birth were 18.2 \u00b1 13.5 ng\/mL. The incidence of VDD was 82.8%, 30.6%, and 27.0% at birth, 6 months, and 12 months, respectively. The incidence of severe VDD (25-OHD &lt; 10 ng\/mL) was 31.5%, 1.5%, and 0%, at birth, 6 months, and 12 months, respectively. Among infants with severe VDD, the deficiency persisted in 49.6% at 6 months, and 35.3% at 12 months. The strongest predictor of VDD during follow-up was 25-OHD concentration at birth. Vitamin D supplementation at 400 IU\/day did not affect vitamin D levels during the first year of life. Therefore, it is important to prevent neonatal VDD through maternal vitamin D supplementation during pregnancy. Further research is needed to determine the optimal vitamin D supplementation dose for Korean preterm infants.<\/jats:p>","DOI":"10.3390\/nu13062019","type":"journal-article","created":{"date-parts":[[2021,6,11]],"date-time":"2021-06-11T12:44:37Z","timestamp":1623415477000},"page":"2019","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Vitamin D Status and Factors Associated with Vitamin D Deficiency during the First Year of Life in Preterm Infants"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4980-0872","authenticated-orcid":false,"given":"Jae-Hun","family":"Jung","sequence":"first","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"},{"name":"Pediatrics, Kyungpook National University, Chilgok Hospital, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eun-Ah","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"},{"name":"Pediatrics, Kyungpook National University, Chilgok Hospital, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sang-Yoon","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"},{"name":"Pediatrics, Kyungpook National University, Chilgok Hospital, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jung-Eun","family":"Moon","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"},{"name":"Pediatrics, Kyungpook National University, Chilgok Hospital, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eun-Joo","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4782-1127","authenticated-orcid":false,"given":"Sook-Hyun","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu 41404, Korea"},{"name":"Pediatrics, Kyungpook National University, Chilgok Hospital, Daegu 41404, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.imlet.2019.03.017","article-title":"The molecular and clinical evidence of vitamin D signaling as a modulator of the immune system: Role in Beh\u00e7et\u2019s disease","volume":"210","author":"Shirvani","year":"2019","journal-title":"Immunol. 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