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- Enlund-Cerullo, M, et al.
(author)
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Genetic Variation of the Vitamin D Binding Protein Affects Vitamin D Status and Response to Supplementation in Infants
- 2019
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 104:11, s. 5483-5498
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Journal article (peer-reviewed)abstract
- ContextSingle nucleotide polymorphisms (SNPs) of the vitamin D binding protein encoding the GC (group component) gene affect 25-hydroxyvitamin D (25OHD) concentrations, but their influence on vitamin D status and response to vitamin D supplementation in infants is unknown.ObjectiveTo study GC genotype–related differences in 25OHD concentrations and the response to supplementation during a vitamin D intervention study in infants.DesignIn this randomized controlled trial, healthy term infants received vitamin D3 (10 or 30 μg/d) from 2 weeks to 24 months of age. GC SNPs rs2282679, rs4588, rs7041, and rs1155563 were genotyped. rs4588/7041 diplotype and haplotypes of rs2282679, rs4588, and rs7041 (Haplo3SNP) and of all four SNPs (Haplo4SNP) were determined.Main Outcome Measures25OHD measured in cord blood at birth and at 12 and 24 months during intervention.ResultsA total of 913 infants were included. Minor allele homozygosity of all studied GC SNPs, their combined haplotypes, and rs4588/rs7041 diplotype 2/2 were associated with lower 25OHD concentrations at all time points in one or both intervention groups [analysis of covariance (ANCOVA) P < 0.043], with the exception of rs7041, which did not affect 25OHD at birth. In the high-dose supplementation group receiving 30 μg/d vitamin D3, but not in those receiving 10 µg/d, genotype of rs2282679, rs4588, and rs7041; diplotype; and Haplo3SNP significantly affected intervention response (repeated measurement ANCOVA Pinteraction < 0.019). Minor allele homozygotes had lower 25OHD concentrations and smaller increases in 25OHD throughout the intervention.ConclusionsIn infants, vitamin D binding protein genotype affects 25OHD concentration and efficiency of high-dose vitamin D3 supplementation.
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- Valkama, S, et al.
(author)
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No Severe Hypercalcemia with Daily Vitamin D3 Supplementation of up to 30 µg during the First Year of Life
- 2017
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In: Hormone research in paediatrics. - : S. Karger AG. - 1663-2826 .- 1663-2818. ; 88:2, s. 147-154
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Journal article (peer-reviewed)abstract
- <b><i>Background:</i></b> Vitamin D supplementation is widely recommended for infants, but the optimal dose remains unclear. High intake may result in hypercalcemia. <b><i>Methods:</i></b> We evaluated the incidence of hypercalcemia during the first year of life in a cohort of 987 healthy children who received 10 or 30 μg of vitamin D<sub>3</sub> supplementation daily. Ionized calcium (Ca-ion) was analyzed at 6 and 12 months, and serum 25-hydroxyvitamin D (25-OHD) and parathyroid hormone (PTH) concentration at 12 months. Severe hypercalcemia was defined as Ca-ion exceeding the reference limit (1.16–1.39 mmol/L) by 10%. <b><i>Results:</i></b> No severe hypercalcemia occurred. Mild hypercalcemia (1.40–1.52 mmol/L) was present at 6 months in 28% and at 12 months in 2% of infants. At 12 months, 25-OHD ranged between 23 and 241 nmol/L (median 97), and PTH was between undetectable and 104 pg/mL (median 24) and was below the reference range (11.5–78.4 pg/mL) in 11%. 25-OHD and Ca-ion correlated positively (<i>r</i> = 0.149), and 25-OHD was slightly higher in the 12 infants with mild hypercalcemia (median 97 vs. 110 nmol/L, <i>p</i> = 0.046). <b><i>Conclusions:</i></b> Vitamin D<sub>3</sub> supplementation of 10 or 30 µg did not cause severe hypercalcemia. Mild hypercalcemia was more prevalent at 6 months than at 12 months, and was associated weakly with 25-OHD at 12 months.
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