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CONTEXT: Single-nucleotide polymorphisms (SNPs) in genes related to vitamin D metabolism have been associated with serum 25-hydroxyvitamin D [25(OH)D] concentration, but these relationships have not been examined following antenatal cholecalciferol supplementation. OBJECTIVE: To determine whether SNPs in DHCR7, CYP2R1, CYP24A1, and GC are associated with the response to gestational cholecalciferol supplementation. DESIGN: Within-randomization group analysis of the Maternal Vitamin D Osteoporosis Study trial of antenatal cholecalciferol supplementation. SETTING: Hospital antenatal clinics. PARTICIPANTS: In total, 682 women of white ethnicity (351 placebo, 331 cholecalciferol) were included. SNPs at rs12785878 (DHCR7), rs10741657 (CYP2R1), rs6013897 (CYP24A1), and rs2282679 (GC) were genotyped. INTERVENTIONS: 1000 IU/d cholecalciferol from 14 weeks of gestation until delivery. MAIN OUTCOME MEASURE: 25(OH)D at randomization and 34 weeks of gestation were measured in a single batch (Liaison; Diasorin, Dartford, UK). Associations between 25(OH)D and the SNPs were assessed by linear regression using an additive model [β represents the change in 25(OH)D per additional common allele]. RESULTS: Only rs12785878 (DHCR7) was associated with baseline 25(OH)D [β = 3.1 nmol/L; 95% confidence interval (CI), 1.0 to 5.2 nmol/L; P < 0.004]. In contrast, rs10741657 (CYP2R1) (β = -5.2 nmol/L; 95% CI, -8.2 to -2.2 nmol/L; P = 0.001) and rs2282679 (GC) (β = 4.2 nmol/L; 95% CI, 0.9 to 7.5 nmol/L; P = 0.01) were associated with achieved 25(OH)D status following supplementation, whereas rs12785878 and rs6013897 (CYP24A1) were not. CONCLUSIONS: Genetic variation in DHCR7, which encodes 7-dehyrocholesterol reductase in the epidermal vitamin D biosynthesis pathway, appears to modify baseline 25(OH)D. In contrast, the response to antenatal cholecalciferol supplementation was associated with SNPs in CYP2R1, which may alter 25-hydroxylase activity, and GC, which may affect vitamin D binding protein synthesis or metabolite affinity.

Original publication

DOI

10.1210/jc.2017-00682

Type

Journal article

Journal

J clin endocrinol metab

Publication Date

01/08/2017

Volume

102

Pages

2941 - 2949

Keywords

Adult, Alleles, Cholecalciferol, Cholestanetriol 26-Monooxygenase, Cytochrome P450 Family 2, Dietary Supplements, Double-Blind Method, Female, Genotype, Humans, Linear Models, Multivariate Analysis, Oxidoreductases Acting on CH-CH Group Donors, Polymorphism, Single Nucleotide, Pregnancy, Treatment Outcome, Vitamin D, Vitamin D Deficiency, Vitamin D-Binding Protein, Vitamin D3 24-Hydroxylase, Vitamins, Young Adult