Vitamin D is a steroid hormone precursor that is associated with a range of human traits and diseases. Previous GWAS of serum 25-hydroxyvitamin D concentrations have identified four genome-wide significant loci (GC, NADSYN1/DHCR7, CYP2R1, CYP24A1). In this study, we expand the previous SUNLIGHT Consortium GWAS discovery sample size from 16,125 to 79,366 (all European descent). This larger GWAS yields two additional loci harboring genome-wide significant variants (P = 4.7×10−9 at rs8018720 in SEC23A, and P = 1.9×10−14 at rs10745742 in AMDHD1). The overall estimate of heritability of 25-hydroxyvitamin D serum concentrations attributable to GWAS common SNPs is 7.5%, with statistically significant loci explaining 38% of this total. Further investigation identifies signal enrichment in immune and hematopoietic tissues, and clustering with autoimmune diseases in cell-type-specific analysis. Larger studies are required to identify additional common SNPs, and to explore the role of rare or structural variants and gene–gene interactions in the heritability of circulating 25-hydroxyvitamin D levels.

Genome-wide association study in 79,366 European-ancestry individuals informs the genetic architecture of 25-hydroxyvitamin D levels

Maternal vitamin D status in pregnancy is a suggested determinant of bone-mineral content (BMC) in offspring, but has been assessed in small studies. The authors investigated this association in a large prospective study.

Association of maternal vitamin D status during pregnancy with bone-mineral content in offspring: a prospective cohort study

Background We previously reported the results of a trial of prenatal vitamin D supplementation to prevent asthma and recurrent wheeze in young children, which suggested that supplementatio...

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Six-Year Follow-up of a Trial of Antenatal Vitamin D for Asthma Reduction.

Importance Severe asthma exacerbations cause significant morbidity and costs. Whether vitamin D3supplementation reduces severe childhood asthma exacerbations is unclear. Objective To determine whether vitamin D3supplementation improves the time to a severe exacerbation in children with asthma and low vitamin D levels. Design, Setting, and Participants The Vitamin D to Prevent Severe Asthma Exacerbations (VDKA) Study was a randomized, double-blind, placebo-controlled clinical trial of vitamin D3supplementation to improve the time to severe exacerbations in high-risk children with asthma aged 6 to 16 years taking low-dose inhaled corticosteroids and with serum 25-hydroxyvitamin D levels less than 30 ng/mL. Participants were recruited from 7 US centers. Enrollment started in February 2016, with a goal of 400 participants; the trial was terminated early (March 2019) due to futility, and follow-up ended in September 2019. Interventions Participants were randomized to vitamin D3, 4000 IU/d (n = 96), or placebo (n = 96) for 48 weeks and maintained with fluticasone propionate, 176 μg/d (6-11 years old), or 220 μg/d (12-16 years old). Main Outcomes and Measures The primary outcome was the time to a severe asthma exacerbation. Secondary outcomes included the time to a viral-induced severe exacerbation, the proportion of participants in whom the dose of inhaled corticosteroid was reduced halfway through the trial, and the cumulative fluticasone dose during the trial. Results Among 192 randomized participants (mean age, 9.8 years; 77 girls [40%]), 180 (93.8%) completed the trial. A total of 36 participants (37.5%) in the vitamin D3group and 33 (34.4%) in the placebo group had 1 or more severe exacerbations. Compared with placebo, vitamin D3supplementation did not significantly improve the time to a severe exacerbation: the mean time to exacerbation was 240 days in the vitamin D3group vs 253 days in the placebo group (mean group difference, −13.1 days [95% CI, −42.6 to 16.4]; adjusted hazard ratio, 1.13 [95% CI, 0.69 to 1.85];P = .63). Vitamin D3supplementation, compared with placebo, likewise did not significantly improve the time to a viral-induced severe exacerbation, the proportion of participants whose dose of inhaled corticosteroid was reduced, or the cumulative fluticasone dose during the trial. Serious adverse events were similar in both groups (vitamin D3group, n = 11; placebo group, n = 9). Conclusions and Relevance Among children with persistent asthma and low vitamin D levels, vitamin D3supplementation, compared with placebo, did not significantly improve the time to a severe asthma exacerbation. The findings do not support the use of vitamin D3supplementation to prevent severe asthma exacerbations in this group of patients. Trial Registration ClinicalTrials.gov Identifier:NCT02687815

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Effect of Vitamin D3 Supplementation on Severe Asthma Exacerbations in Children With Asthma and Low Vitamin D Levels: The VDKA Randomized Clinical Trial.

The last couple of decades have seen an explosion in our interest and understanding of the role of vitamin D in the regulation of immunity. At the molecular level, the hormonal form of vitamin D signals through the nuclear vitamin D receptor (VDR), a ligand-regulated transcription factor. The VDR and vitamin D metabolic enzymes are expressed throughout the innate and adaptive arms of the immune system. The advent of genome-wide approaches to gene expression profiling have led to the identification of numerous VDR-regulated genes implicated in the regulation of innate and adaptive immunity. The molecular data infer that vitamin D signaling should boost innate immunity against pathogens of bacterial or viral origin. Vitamin D signaling also suppresses inflammatory immune responses that underlie autoimmunity and regulate allergic responses. These findings have been bolstered by clinical studies linking vitamin D deficiency to increased rates of infections, autoimmunity, and allergies. Our goals here are to provide an overview of the molecular basis for immune system regulation and to survey the clinical data from pediatric populations, using randomized placebo-controlled trials and meta-analyses where possible, linking vitamin D deficiency to increased rates of infections, autoimmune conditions, and allergies, and addressing the impact of supplementation on these conditions.

https://www.mdpi.com/2072-6643/12/5/1233/pdf

Vitamin D and Immunity in Infants and Children.

This long-term follow-up of a randomized trial reporting no apparent effect of high-dose vs standard-dose prenatal vitamin D supplementation on wheezing in children at the age of 3 years extends the findings an additional 3 years and describes asthma risk at the age of 6 years.

High-Dose Vitamin D Supplementation During Pregnancy and Asthma in Offspring at the Age of 6 Years.

The pregnancy period and first days of a newborn’s life is an important time window to ensure a healthy development of the baby. This is also the time when the mother and her baby are exposed to the same environmental conditions and intake of nutrients, which can be determined by assessing the blood metabolome. For this purpose, dried blood spots (DBS) of newborns are a valuable sampling technique to characterize what happens during this important mother-child time window. We used metabolomics profiles from DBS of newborns (age 2–3 days) and maternal plasma samples at gestation week 24 and postpartum week 1 from n=664 mother-child pairs of the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort, to study the vertical mother-child transfer of metabolites. Further, we investigated how persistent the metabolites are from the newborn and up to 6 months, 18 months, and 6 years of age. Two hundred seventy two metabolites from UPLC-MS (Ultra Performance Liquid Chromatography-Mass Spectrometry) analysis of DBS and maternal plasma were analyzed using correlation analysis. A total of 11 metabolites exhibited evidence of transfer (R>0.3), including tryptophan betaine, ergothioneine, cotinine, theobromine, paraxanthine, and N6-methyllysine. Of these, 7 were also found to show persistence in their levels in the child from birth to age 6 years. In conclusion, this study documents vertical transfer of environmental and food-derived metabolites from mother to child and tracking of those metabolites through childhood, which may be of importance for the child’s later health and disease.

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Vertical Transfer of Metabolites Detectable from Newborn’s Dried Blood Spot Samples Using UPLC-MS: A Chemometric Study

Aquagenic wrinkling of the palms (AWP) is a condition characterized by oedema, confluent white papules and excessive wrinkling of the palms after few minutes exposure to water. The phenomenon may be associated with pain, numbness and pruritus1,2 . It was first noticed and described in 1974 in children with cystic fibrosis (CF) by a paediatrician R.B. Elliott3 . This article is protected by copyright. All rights reserved.

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Aquagenic wrinkling of the palms in patients with cystic fibrosis.

Vitamin D insufficiency has become a common health problem worldwide, particularly among pregnant women and young children. Therefore, we sought to identify environmental, dietary, and genetic determinants of serum 25(OH)-vitamin D (25(OH)D) levels during pregnancy and early childhood. 25(OH)D was measured in women at 24-weeks of gestation (n = 738) and one-week postpartum (n = 284) in the population-based Danish COPSAC2010 mother-child cohort; and in cord blood (n = 257) and age 4 years (n = 298) in children from the at-risk COPSAC2000 mother-child cohort. Environmental, dietary, and genetic variables were tested for association with 25(OH)D using linear regression analyses. After adjusting for season of blood sampling, determinants of lower 25(OH)D levels during pregnancy in the women were higher pre-pregnancy BMI, lower age at birth, lower genetic vitamin D score, lower dietary vitamin D intake, and lower social circumstances. In children, the determinants were lower maternal age at birth, higher pre-pregnancy BMI, lower genetic vitamin D score, older siblings, exposure to tobacco smoking, and female sex. Genetics was an important determinant at all time points, alone explaining 2%-11% of the variance in 25(OH)D. Important determinants of circulating 25(OH)D levels during pregnancy and early childhood include environmental factors, diet, and to a large extent genetics.

Environmental and Genetic Determinants of Serum 25(OH)-Vitamin D Levels during Pregnancy and Early Childhood.

Key Points Question Is high-dose vitamin D supplementation safe for children aged 0 to 6 years? Findings In this systematic review and meta-analysis of 32 randomized clinical trials including 8400 unique children, high-dose vitamin D administered as a daily or bolus supplement was not associated with an increased risk of serious adverse events. Clinical adverse events associated with the supplementation were rare. Meaning This systematic review and meta-analysis suggests that vitamin D supplements in daily doses to 10 000 IU/d or bolus doses to 600 000 IU are well tolerated in children aged 0 to 6 years.

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Nicklas Brustad

Papers

High-Dose Vitamin D Supplementation During Pregnancy and Asthma in Offspring at the Age of 6 Years.

Vertical Transfer of Metabolites Detectable from Newborn’s Dried Blood Spot Samples Using UPLC-MS: A Chemometric Study

Aquagenic wrinkling of the palms in patients with cystic fibrosis.

Environmental and Genetic Determinants of Serum 25(OH)-Vitamin D Levels during Pregnancy and Early Childhood.

Safety of High-Dose Vitamin D Supplementation Among Children Aged 0 to 6 Years