{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T22:30:54Z","timestamp":1791844254975,"version":"4.3.4"},"reference-count":0,"publisher":"Oxford University Press (OUP)","issue":"2","content-domain":{"domain":["eje.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2021,8,1]]},"abstract":"<jats:sec>\n<jats:title>Objective<\/jats:title>\n<jats:p>GC\/DBP effects on response to vitamin D supplementation have not been well-studied. Thus we assessed free and total 25-OHD after vitamin D treatment across the six common <jats:italic>GC<\/jats:italic> haplotypes.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Design<\/jats:title>\n<jats:p>This double-blind, randomized study compared two vitamin D<jats:sub>3<\/jats:sub> doses in healthy, urban-dwelling 6-month to 10-year-old children at-risk for vitamin D deficiency. Randomization was stratified by <jats:italic>GC<\/jats:italic> haplotype.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Methods<\/jats:title>\n<jats:p>Children were randomized to receive 2800 or 7000 International Units of vitamin D<jats:sub>3<\/jats:sub> weekly. 25-OHD and 1,25(OH)<jats:sub>2<\/jats:sub>D were sampled at baseline and after 1\u20136 months of supplementation.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Results and conclusions<\/jats:title>\n<jats:p>One hundred ninety-two of 225 enrolled subjects completed the study. After one month, total 25-OHD increased with both doses and were higher with 7000 IU\/week (85.5 \u00b1 22.8 nmol\/L) compared to 2800 IU\/week (76.8 \u00b1 18.0 nmol\/L), despite equivalent baseline levels. No further significant increase occurred at 6 months (89.8 \u00b1 35.5 and 74.3 \u00b1 18.3 nmol\/L, respectively). Free 25-OHD similarly changed. 25-OHD differed among <jats:italic>GC<\/jats:italic> groups at baseline. Although no significant effects of individual <jats:italic>GC<\/jats:italic> haplotypes on incremental changes were evident, a trend toward an effect of combined 'at risk' <jats:italic>GC<\/jats:italic> alleles on response was evident (<jats:italic>P<\/jats:italic>\u2009=\u20090.06). Total 1,25(OH)<jats:sub>2<\/jats:sub>D showed modest increases, moreso with the larger dose. In urban-dwelling children at-risk for vitamin D deficiency, 1 month of vitamin D<jats:sub>3<\/jats:sub> 2800 IU\/week increased 25-OHD across all <jats:italic>GC<\/jats:italic> haplotype groups, and somewhat enhanced with 7000 IU\/week with no further significant increases after 6 months of supplementation. Free 25-OHD measures offer no monitoring advantage over total 25-OHD.<\/jats:p>\n<\/jats:sec>","DOI":"10.1530\/eje-21-0349","type":"journal-article","created":{"date-parts":[[2021,6,15]],"date-time":"2021-06-15T14:22:47Z","timestamp":1623766967000},"page":"333-342","update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-7","source":"Crossref","is-referenced-by-count":5,"title":["25-OHD response to vitamin D supplementation in children: effect of dose but not GC haplotype"],"prefix":"10.1093","volume":"185","author":[{"given":"Christine A","family":"Simpson","sequence":"first","affiliation":[{"name":"1Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jane H","family":"Zhang","sequence":"additional","affiliation":[{"name":"2Veterans Administration Cooperative Studies Program Coordinating Center, VA Connecticut Healthcare System, West Haven, Connecticut, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dirk","family":"Vanderschueren","sequence":"additional","affiliation":[{"name":"3Department of Chronic Diseases, Metabolism and Ageing, Laboratory of Clinical and Experimental Endocrinology, Katholieke Universiteit Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Fu","sequence":"additional","affiliation":[{"name":"4Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada"},{"name":"5Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Teresita C","family":"Pennestri","sequence":"additional","affiliation":[{"name":"7Department of Pediatrics (Endocrinology), Yale University School of Medicine, New Haven, Connecticut, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roger","family":"Bouillon","sequence":"additional","affiliation":[{"name":"3Department of Chronic Diseases, Metabolism and Ageing, Laboratory of Clinical and Experimental Endocrinology, Katholieke Universiteit Leuven, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David E C","family":"Cole","sequence":"additional","affiliation":[{"name":"6Departments of Laboratory Medicine and Pathobiology, Medicine, and Genetics, University of Toronto, and Sunnybrook Health Center, Toronto, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas O","family":"Carpenter","sequence":"additional","affiliation":[{"name":"7Department of Pediatrics (Endocrinology), Yale University School of Medicine, New Haven, Connecticut, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","container-title":["European Journal of Endocrinology"],"original-title":[],"link":[{"URL":"https:\/\/eje.bioscientifica.com\/view\/journals\/eje\/185\/2\/EJE-21-0349.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/eje.bioscientifica.com\/downloadpdf\/journals\/eje\/185\/2\/EJE-21-0349.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,2,14]],"date-time":"2023-02-14T16:16:39Z","timestamp":1676391399000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/ejendo\/article\/185\/2\/333\/6654388"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,1]]},"references-count":0,"journal-issue":{"issue":"2"},"URL":"https:\/\/doi.org\/10.1530\/eje-21-0349","relation":{},"ISSN":["0804-4643","1479-683X"],"issn-type":[{"value":"0804-4643","type":"print"},{"value":"1479-683X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,1]]}}}