biostudies-literatureSimpson CANCATS NIH HHSNICHD NIH HHSNCRR NIH HHS333-342https://www.ebi.ac.uk/biostudies/studies/S-EPMC8284876biostudies-literatureUnknown185(2)<h4>Objective</h4>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 GC haplotypes.<h4>Design</h4>This double-blind, randomized study compared two vitamin D3 doses in healthy, urban-dwelling 6-month to 10-year-old children at-risk for vitamin D deficiency. Randomization was stratified by GC haplotype.<h4>Methods</h4>Children were randomized to receive 2800 or 7000 International Units of vitamin D3 weekly. 25-OHD and 1,25(OH)2D were sampled at baseline and after 1-6 months of supplementation.<h4>Results and conclusions</h4>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 IEuropean journal of endocrinology25-OHD response to vitamin D supplementation in children: effect of dose but not GC haplotype.PMC8284876RC1 HD063562UL1 RR024139UL1 TR001863Vanderschueren DSimpson CABouillon RZhang JHPennestri TCFu LCole DECCarpenter TOfalse25-OHD response to vitamin D supplementation in children: effect of dose but not GC haplotype.<h4>Objective</h4>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 GC haplotypes.<h4>Design</h4>This double-blind, randomized study compared two vitamin D3 doses in healthy, urban-dwelling 6-month to 10-year-old children at-risk for vitamin D deficiency. Randomization was stratified by GC haplotype.<h4>Methods</h4>Children were randomized to receive 2800 or 7000 International Units of vitamin D3 weekly. 25-OHD and 1,25(OH)2D were sampled at baseline and after 1-6 months of supplementation.<h4>Results and conclusions</h4>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 I2021-01-01T00:00:00Z2021 Jul2026-05-01T03:12:26.634Z2022-07-23T18:59:46.665ZS-EPMC82848763412882610.1530/EJE-21-034910.1530/eje-21-0349