25-Hydroxyvitamin D and Peripheral Immune Mediators: Results from Two Nationwide Danish Pediatric Cohorts

High Initial Dose of Monitored Vitamin D Supplementation in Preterm Infants (HIDVID Trial): Study Protocol for a Randomized Controlled Study

Vitamin D deficiency can escalate prematurity bone disease in preterm infants and negatively influence their immature immunology system. Infants born at 24 + 0/7 weeks to 32 + 6/7 weeks of gestation will be considered for inclusion. Cord or vein blood samples will be obtained within 48 h after birth for 25-hydroxyvitamin D level measurements. Parathyroid hormone and interleukin-6 levels will be measured. Infants will be randomized to the monitored group (i.e., an initial dose of 1000 IU/day and possible modification) or the controlled group (i.e., 250 IU/day or 500 IU/day dose, depending on weight). Supplementation will be monitored up to a postconceptional age of 35 weeks. The primary endpoint is the percentage of infants with deficient or suboptimal 25-hydroxyvitamin D levels at 28 ± 2 days of age. 25-Hydroxyvitamin D levels will be measured at postconceptional age 35 ± 2 weeks. Secondary goals encompass assessing the occurrence of sepsis, osteopenia, hyperparathyroidism, and interleukin-6 concentration. The aim of this study is to evaluate the efficacy of monitored vitamin D supplementation in a group of preterm infants and ascertain if a high initial dosage of monitored vitamin D supplementation can decrease the occurrence of neonatal sepsis and metabolic bone disease.

Maternal and Cord Blood 25-Hydroxyvitamin D3 Are Associated with Increased Cord Blood and Naive and Activated Regulatory T Cells: The Barwon Infant Study

Vitamin D has shown immune-modulatory effects but mostly in in vitro and animal studies. Regulatory T cells (Treg) are important for a balanced immune system. The relationship between vitamin D on the number of circulating neonatal Treg is unclear. We sought to investigate the association between maternal and neonatal vitamin D metabolites and cord blood (CB) Treg subsets. In a cohort of Australian infants (n = 1074), recruited using an unselected antenatal sampling frame, 158 mother-infant pairs had data on the following: 1) 25-hydroxyvitamin D₃ (25(OH)D₃) measures in both maternal peripheral blood (28- to 32-wk gestation) and infant CB; 2) proportions (percentage of CD4⁺ T cells) of CB Treg subsets (CD4⁺CD45RA⁺ FOXP3^low naive Treg, and CD4⁺CD45RA^- FOXP3^high activated Treg [aTreg]); and 3) possible confounders, including maternal personal UV radiation. Multiple regression analyses were used. The median 25(OH)D₃ was 85.4 and 50.7 nmol/l for maternal and CB samples, respectively. Higher maternal 25(OH)D₃ levels were associated with increased CB naive Treg (relative adjusted mean difference [AMD] per 25 nmol/l increase: 5%; 95% confidence interval [CI]: 1-9%), and aTreg (AMD per 25 nmol/l increase: 17%; 95% CI: 6-28%). Furthermore, a positive association between CB 25(OH)D₃ levels and CB aTreg (AMD per 25 nmol/l increase: 29%; 95% CI: 13-48%) was also evident. These results persisted after adjustment for other factors such as maternal personal UV radiation and season of birth. 25(OH)D_3, may play a role in the adaptive neonatal immune system via induction of FOXP3⁺ Tregs. Further studies of immune priming actions of antenatal 25(OH)D₃ are warranted.

Association Between Vitamin D Receptor Gene Polymorphism rs2228570 and Allergic Rhinitis

Background

Vitamin D receptor (VDR) gene polymorphisms are involved in a variety of immune-related diseases, and VDR is associated with allergic rhinitis. The present study explored the associations between VDR gene polymorphisms and allergic rhinitis in the Chinese population.

Methods

The study population consisted of 400 patients with allergic rhinitis and 400 healthy controls. General characteristics were determined by interview. Blood DNA was extracted and genotyping was performed via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The associations of each genetic variant with risk for AR were assessed by calculating the odds ratio (OR) with 95% confidence interval (95% CI).

Results

No significant differences were observed in general characteristics between cases and controls. The distributions of genotypes at the rs2228570 locus of the VDR gene conformed to Hardy–Weinberg equilibrium. There was a significant difference in the distribution of rs2228570 genotype (P<0.001) between cases and controls. Compared to GG and GA genotypes, the AA genotype increased the risk of AR (OR=3.27, 95% CI: 2.10–5.11, P=0.000; OR=2.58, 95% CI:1.63–4.08, P<0.001). Similar results were also observed in the dominant model (OR=1.64, 95% CI:1.24–2.17, P<0.001) and codominant model (OR=2.95, 95% CI:1.93–4.51, P<0.001). The A allele was still associated with elevated risk gene for AR after adjusting for potential confounding factors. Subgroup analyses indicated an interaction between alcohol and rs2228570 in the risk of allergic rhinitis. The A allele also increased the risk for AR in the population without asthma (OR=1.85, 95% CI:1.46–2.34, P<0.001).

Conclusion

VDR gene polymorphism is associated with AR, and the AA genotype of rs2228570 is associated with the increased risk of AR in the Chinese population.

Effect of 25-hydroxyvitamin D on Helicobacter pylori eradication in patients with type 2 diabetes

BACKGROUND

Various studies have reported a lower Helicobacter pylori eradication rate and a more frequent reinfection rate in type 2 diabetes mellitus (T2DM). Vitamin D has anti-inflammatory and immunoregulatory activity and the role of the vitamin D receptor (VDR) in the antimicrobial activity against H. pylori has been reported. When it comes to the risk factors of H. pylori eradication, the function of vitamin D is not always taken into account. The aim of this study was to assess the role of 25-hydroxyvitamin D in H. pylori eradication in T2DM.

METHODS

In this retrospective study data from 160 patients with T2DM who underwent eradication therapy for H. pylori in Anhui Provincial Hospital between July 2015 and September 2017 were analyzed. According to eradication status, patients were divided into two groups, the successful eradication group (n = 124) and the eradication failure group (n = 36). The following information was obtained from participants' records before eradication treatment: age, sex, body mass index (BMI), duration of T2DM, prescription of medication use, smoking and drinking history. All patients were tested for glycated hemoglobin (HbA1c), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL‑C), triglyceride (TG) and 25-hydroxyvitamin D (25-OHD) at baseline.

RESULTS

The H. pylori was eradicated in 124 (77.5%) patients, while in 36 (22.5%) patients the treatment was unsuccessful. The eradication failure group had a lower mean vitamin D concentration than the group with successful eradication (15.09 ± 7.72 ng/ml vs. 19.87 ± 6.35 ng/ml, p = 0.004). The estimated odds ratio (OR) for eradication failure in individuals with serum vitamin D deficiency (<20 ng/ml) compared to those with sufficient vitamin D levels (>30 ng/ml) were 1.489 (95% confidence interval, CI: 1.046-2.121, P = 0.027), Individuals with long duration of diabetes (≥10 years) had odds of eradication failure of 1.467 (95% CI: 1.017-2.114, P = 0.040) compared to subjects with short duration of diabetes (<10 years).

CONCLUSIONS

Lower 25-OHD was not only associated with H. pylori eradication failure but was also related to dyslipidemia in T2DM patients. Increasing serum 25-OHD to appropriate levels by activated vitamin D use may improve the eradication rate.