The role of interaction between vitamin D and VDR FokI gene polymorphism (rs2228570) in sleep quality of adults

To evaluate association of vitamin D with sleep quality in adults and the influence of VDR-gene polymorphism FokI (rs2228570;A > G). Cross-sectional population-based study in adults, conducted in Brazil. The outcome was sleep-quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D was determined by indirect electrochemiluminescence and classified as deficiency (VDD), 25(OH)D < 20 ng/mL in a healthy population or 25(OH)D < 30 ng/mL for groups at risk for VDD. FokI polymorphism in the VDR-gene was genotyped by qPCR and classified as homozygous wild (FF or AA), heterozygous (Ff or AG), or homozygous mutant (ff or GG). Multivariate logistic analysis was used to estimate the association between vitamin D and FokI polymorphism with sleep-quality. In a total of 1674 individuals evaluated, 53.6% had poor-sleep-quality, 31.5% had VDD, and the genotype frequency of the FokI polymorphism was 9.9% FF, 44.6% Ff, and 45.5% ff. In multivariate analysis, individuals with VDD had 1.51 times the chance of poor-sleep-quality, and individuals with the ff genotype had 1.49 times the chance of poor-sleep-quality (OR:1.49;95%CI:1.05-2.12) when compared to individuals with the FF or Ff genotype. In the combined analysis, individuals with VDD and ff genotype had more chance of poor-sleep-quality than individuals with sufficient vitamin D and genotype Ff or FF (OR:2.19;95%CI:1.27-3.76). Our data suggest that VDD and VDR FokI gene polymorphism are associated with poor-sleep-quality, and combining the two factors increases the chance of poor-sleep-quality compared to separate groups.

Vitomics: A novel paradigm for examining the role of vitamins in human biology

The conventional view of vitamins reflects a diverse group of small molecules that facilitate critical aspects of metabolism and prevent potentially fatal deficiency syndromes. However, vitamins also contribute to the shaping and maintenance of the human phenome over lifecycle and evolutionary timescales, enabling a degree of phenotypic plasticity that operates to allow adaptive responses that are appropriate to key periods of sensitivity (i.e., epigenetic response during prenatal development within the lifecycle or as an evolved response to environmental challenge over a great many lifecycles). Individually, vitamins are important, but their effect is often based on nutrient-nutrient (vitamin-vitamin), nutrient-gene (vitamin-gene), and gene-gene interactions, and the environmental influence of shifting geophysical cycles, as well as evolving cultural practices. These ideas will be explored within what I refer to as the "adaptive vitome (vitomics)" paradigm.

Vitamin D and depression in older adults: lessons learned from observational and clinical studies

Depression is a mental disorder triggered by the interaction of social, psychological and biological factors that have an important impact on an individual's life. Despite being a well-studied disease with several established forms of treatment, its prevalence is increasing, especially among older adults. New forms of treatment and prevention are encouraged, and some researchers have been discussing the effects of vitamin D (VitD) on depression; however, the exact mechanism by which VitD exerts its effects is not yet conclusive. In this study, we aimed to discuss the possible mechanisms underlying the association between VitD and depression in older adults. Therefore, we conducted a systematic search of databases for indexed articles published until 30 April 2021. The primary focus was on both observational studies documenting the association between VitD and depression/depressive symptoms, and clinical trials documenting the effects of VitD supplementation on depression/depressive symptoms, especially in older adults. Based on pre-clinical, clinical and observational studies, it is suggested that the maintenance of adequate VitD concentrations is an important issue, especially in older adults, which are a risk population for both VitD deficiency and depression. Nevertheless, it is necessary to carry out more studies using longitudinal approaches in low- and middle-income countries to develop a strong source of evidence to formulate guidelines and interventions.

The Mediation Role of Sleep Disturbances between Vitamin D and Depressive Symptoms: A Cross-Sectional Study

Depression and sleep disturbances are highly prevalent health problems that have been suggested to be associated with vitamin D deficiency. This study investigated whether sleep disturbances affect the association between vitamin D and depressive symptoms. A total of 425 patients with depression were included in this study. Spearman correlation coefficients were chosen to assess the relation between vitamin D concentrations and depressive symptomatology (according to the PHQ-9 and HAMD-17 scores). The GLM Mediation Model in the Medmod module for data analysis in Jamovi 2.2.5 was used to analyze the mediation models for sleep disturbances. Vitamin D concentrations were significantly correlated with PHQ-9 and HAMD-17 scale scores. In addition, item 3 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of PHQ-9, and item 4 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of HAMD-17. Sleep disturbances (especially difficulty falling asleep) are mediators between vitamin D and depressive symptoms, suggesting that increasing vitamin D levels at the right time to regulate sleep disturbances may improve depression symptoms, yet further research is necessary.

Influence of sunlight on the association between 25-hydroxyvitamin D levels and sleep quality in Brazilian adults: A population-based study

OBJECTIVES

This study aimed to evaluate the association of vitamin D with sleep quality during the COVID-19 pandemic and the influence of daily sunlight on this association.

METHODS

This cross-sectional, population-based study among adults stratified by multistage probability cluster sampling was conducted from October to December 2020 in the Iron Quadrangle region of Brazil. The outcome was sleep quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D (25-hydroxyvitamin D) concentrations were determined by indirect electrochemiluminescence and a deficiency was classified as 25(OH)D < 20 ng/mL. To assess sunlight, the average daily sunlight exposure was calculated and was classified as insufficient when less than 30 min/d. Multivariate logistic analysis was used to estimate the association between vitamin D and sleep quality. A directed acyclic graph was used to select minimal and sufficient sets of adjustment variables for confounding from the backdoor criterion.

RESULTS

In a total of 1709 individuals evaluated, the prevalence of vitamin D deficiency was 19.8% (95% CI, 15.5-24.9%), and the prevalence of poor sleep quality was 52.5% (95% CI, 48.6-56.4%). In multivariate analysis, vitamin D was not associated with poor sleep quality in individuals with sufficient sunlight. Moreover, in individuals with insufficient sunlight, vitamin D deficiency was associated with poor sleep quality (odds ratio [OR], 2.02; 95% CI, 1.10-3.71). Furthermore, each 1-ng/mL increase in vitamin D levels reduced the chance of poor sleep quality by 4.2% (OR, 0.96; 95% CI, 0.92-0.99).

CONCLUSIONS

Vitamin D deficiency was associated with poor sleep quality in individuals with insufficient exposure to sunlight.

The evolution of human skin pigmentation: A changing medley of vitamins, genetic variability, and UV radiation during human expansion

This review examines putative, yet likely critical evolutionary pressures contributing to human skin pigmentation and subsequently, depigmentation phenotypes. To achieve this, it provides a synthesis of ideas that frame contemporary thinking, without limiting the narrative to pigmentation genes alone. It examines how geography and hence the quality and quantity of UV exposure, pigmentation genes, diet-related genes, vitamins, anti-oxidant nutrients, and cultural practices intersect and interact to facilitate the evolution of human skin color. The article has a strong focus on the vitamin D-folate evolutionary model, with updates on the latest biophysical research findings to support this paradigm. This model is examined within a broad canvas that takes human expansion out of Africa and genetic architecture into account. A thorough discourse on the biology of melanization is provided (includes relationship to BH4 and DNA damage repair), with the relevance of this to the UV sensitivity of folate and UV photosynthesis of vitamin D explained in detail, including the relevance of these vitamins to reproductive success. It explores whether we might be able to predict vitamin-related gene polymorphisms that pivot metabolism to the prevailing UVR exposome within the vitamin D-folate evolutionary hypothesis context. This is discussed in terms of a primary adaptive phenotype (pigmentation/depigmentation), a secondary adaptive phenotype (flexible metabolic phenotype based on vitamin-related gene polymorphism profile), and a tertiary adaptive strategy (dietary anti-oxidants to support the secondary adaptive phenotype). Finally, alternative evolutionary models for pigmentation are discussed, as are challenges to future research in this area.

Vitamin D Supplementation and Sleep: A Systematic Review and Meta-Analysis of Intervention Studies

Background: Vitamin D deficiency is associated with sleep disorders and poor sleep quality. Whether vitamin D supplementation (VDS) helps resolve these problems remains unclear. Objective: To systematically review the effect of VDS on sleep quantity, quality, and disorders, and perform a meta-analysis of available data. Methods: The reporting of this review followed the PRISMA statement. VDS human interventions studies that reported on sleep quality, quantity, or disorders were included. Medline, CINAHL, EMBASE, PsycInfo, the Cochrane Library, Clinicaltrials.gov, and the ICTRP were searched, in addition to the references of the included articles and previous relevant reviews, without language or time restrictions. Included studies were critically appraised, findings were narratively synthesized, and a meta-analysis was conducted. Furthermore, the overall certainty of the evidence was assessed. Results: A total of 19 studies were included (13 randomized controlled trials (RCTs), 1 opportunistic addition to an RCT, 4 pre−post studies, and 1 pre−post study analyzed as a case series); 3 RCTs were meta-analyses. The risk of bias was generally low. Pre−post studies showed a significant improvement in sleep quality with VDS. Similarly, the results of the meta-analysis revealed a statistically significant decrease in the Pittsburgh Sleep Quality Index with VDS compared with placebo (mean difference, −2.33 (95% CI, −3.09, −1.57); p < 0.001; I2 = 0%), with a moderate certainty of evidence. The results regarding the effect of VDS on sleep-related impairment, difficulty, and disorders, as well as sleepiness and restless legs syndrome, were not unanimous. Conclusions: VDS is promising in improving sleep quality; however, its effect on sleep quantity and disorders needs to be further investigated.

No improvement of sleep from vitamin D supplementation: insights from a randomized controlled trial

Background

Vitamin D has been linked to sleep health in observational studies. Data from randomized controlled trials (RCTs) with vitamin D is scarce.

Methods

This study presents the results of a secondary analysis of 189 vitamin D insufficient participants (47.1% women) in a previously performed RCT, of which 92 were randomized to vitamin D (100,000 IU (2500 μg) as a bolus dose followed by 20,000 IU (500 μg) per week), and 97 to placebo. At baseline and after 4 months at the end of the study serum 25-hydroxyvitamin D (s-25(OH)D) was measured, and the study questionnaire assessing sleep duration, daytime sleepiness, and symptoms of insomnia, was completed.

Results

At baseline, mean s-25(OH)D was 35.0 ± 11.8 and 35.5 ± 13.3 nmol/L in the vitamin D and placebo groups, respectively. After four months, we found no statistically significant differences between the intervention groups in any of the assessed sleep outcomes, neither when stratified by sex, nor when performed in subgroups based on baseline or end of study s-25(OH)D level or presence of sleep complaints at baseline.

Conclusions

We were not able to demonstrate a significant effect of vitamin D supplementation on sleep in this vitamin D insufficient population.

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RCT investigating vitamin D for 4 months in participants with low vitamin D status.

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Vitamin D did not improve sleep duration, excessive daytime sleepiness or insomnia.

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The role of vitamin D in sleep health remains controversial.

1,25(OH)2 D3 attenuates sleep disturbance in mouse models of Lewis lung cancer, in silico and in vivo

Many clinical studies have reported that patients diagnosed with cancer will suffer from sleep disturbance during their clinical process, especially among lung cancer patients, and this effect will not easily subside. 1,25-dihydroxy-vitamin-D3 [1,25(OH)2 D3 ], the activated form of vitamin D, can participate in neuronal differentiation and prevent damage to the nervous system. However, little is known about the potential therapeutic effects of cancer-related psychiatric symptoms. In light of this, we hypothesized that a low circulating level of vitamin D was related to sleep quality in the presence of a tumor, 1,25(OH)2 D3 may be an effective way to ameliorate sleep disturbance and neurochemical alterations along with the cancer progress. Male C57BL/6 mice were implanted with intracranial transmitters to monitor electroencephalogram and were subcutaneously inoculated with Lewis lung cancer cells. The results demonstrated that on Days 19-20, tumor-bearing mice displayed fragmented sleep, shortened wake phase, prolonged sleep in the non-rapid eye movement phase, and the levels of vitamin D-associated genes in the brain had changed a lot compared to control mice. Importantly, 1,25(OH)2 D3 treatment really effectively saved the sleep quality of tumor-bearing mice. We further explored and confirmed that 1,25(OH)2 D3 repressed tumor-induced neuroinflammation (IL-1β, TNF-α, IL-6, IL-10, IFN-γ, and IL-2), enhanced neurotrophic factors (brain-derived neurotrophic factor [BDNF], glialcellline-derived neurotrophic factor) and 5-HT system in the hippocampus, hypothalamus or cortex. A molecular docking approah manifested the ability of 1,25(OH)2 D3 to affect the activity of tryptophan hydroxylase 2 and BDNF. Together, our results suggested that 1,25(OH)2 D3 treatment may attenuate sleep disturbance in Lewis lung cancer-bearing mice, and become a promising strategy for treating cancer symptom clusters to ameliorate the quality of life of patients with cancer.

Vitamin-related phenotypic adaptation to exposomal factors: The folate-vitamin D-exposome triad

The biological role of two key vitamins, folic acid and vitamin D is so fundamental to life processes, it follows that their UV sensitivity, dietary abundance (both key exposomal factors) and variability in dependent genes will modify their functional efficacy, particularly in the context of maintaining the integrity and function of genome and epigenome. This article therefore examines folate and vitamin D-related phenotypic adaptation to environmental factors which vary across the human life cycle as well as over an evolutionary time-scale. Molecular mechanisms, key nutrigenomic factors, phenotypic maladaptation and evolutionary models are discussed.

Vitamin D and Sleep Regulation: Is there a Role for Vitamin D?

BACKGROUND

Vitamin D exerts multiple pleiotropic effects beyond its role in calcium-phosphate metabolism. Growing evidence suggests an association between hypovitaminosis D and sleep disorders, thus increasing the interest in the role of this vitamin in the regulatory mechanisms of the sleep-wake cycle.

OBJECTIVE

The study aimed to explore and summarize the current knowledge about the role of vitamin D in sleep regulation and the impact of vitamin D deficiency on sleep disorders.

METHODS

The main regulatory mechanisms of vitamin D on sleep are explained in this study. The literature was scanned to identify clinical trials and correlation studies showing an association between vitamin D deficiency and sleep disorders.

RESULTS

Vitamin D receptors and the enzymes that control their activation and degradation are expressed in several areas of the brain involved in sleep regulation. Vitamin D is also involved in the pathways of production of Melatonin, the hormone involved in the regulation of human circadian rhythms and sleep. Furthermore, vitamin D can affect sleep indirectly through non-specific pain disorders, correlated with alterations in sleep quality, such as restless legs syndrome and obstructive sleep apnea syndrome.

CONCLUSION

Vitamin D has both a direct and an indirect role in the regulation of sleep. Although vitamin D deficiency has been associated to sleep disorders, there is still scant evidence to concretely support the role of vitamin D supplementation in the prevention or treatment of sleep disturbances; indeed, more intervention studies are needed to better clarify these aspects.

Adaptation and co-adaptation of skin pigmentation and vitamin D genes in native Americans

We carried out an exhaustive review regarding human skin color variation and how much it may be related to vitamin D metabolism and other photosensitive molecules. We discuss evolutionary contexts that modulate this variability and hypotheses postulated to explain them; for example, a small amount of melanin in the skin facilitates vitamin D production, making it advantageous to have fair skin in an environment with little radiation incidence. In contrast, more melanin protects folate from degradation in an environment with a high incidence of radiation. Some Native American populations have a skin color at odds with what would be expected for the amount of radiation in the environment in which they live, a finding challenging the so-called "vitamin D-folate hypothesis." Since food is also a source of vitamin D, dietary habits should also be considered. Here we argue that a gene network approach provides tools to explain this phenomenon since it indicates potential alleles co-evolving in a compensatory way. We identified alleles of the vitamin D metabolism and pigmentation pathways segregated together, but in different proportions, in agriculturalists and hunter-gatherers. Finally, we highlight how an evolutionary approach can be useful to understand current topics of medical interest.

Vitamin D (1,25-(OH)2D3) Improves Endothelial Progenitor Cells Function via Enhanced NO Secretion in Systemic Lupus Erythematosus

It has been proven that vitamin D was decreased and function of circulating endothelial progenitor cells (EPCs) was injured in systemic lupus erythematosus (SLE) patients. However, the effect of vitamin D on the function of EPCs in vitro and its mechanism need further study. Therefore, we investigated whether vitamin D improved the function of EPCs in vitro. The peripheral blood mononuclear cells of the participants were isolated from SLE patients and control subjects and cultured to EPCs. After the EPCs were treated with vitamin D (1,25-(OH)₂D₃), we evaluated the number, migratory and proliferative activities, and nitric oxide (NO) production of EPCs in vitro and detected vascular endothelial function by flow-mediated dilatation (FMD). We found that vitamin D in a dose-dependent manner improved number and migratory and proliferative activities of EPCs from SLE patients. Additionally, vitamin D upregulated NO production from EPCs in vitro. A significant correlation between the FMD and plasma NO level was found. There was also a correlation between number, migration, and proliferation of EPCs and NO production. Thus, the present findings indicated that vitamin D improved the function of EPCs from SLE patients via NO secretion.

Understanding the Biological Activities of Vitamin D in Type 1 Neurofibromatosis: New Insights into Disease Pathogenesis and Therapeutic Design

Vitamin D is a fat-soluble steroid hormone playing a pivotal role in calcium and phosphate homeostasis as well as in bone health. Vitamin D levels are not exclusively dependent on food intake. Indeed, the endogenous production-occurring in the skin and dependent on sun exposure-contributes to the majority amount of vitamin D present in the body. Since vitamin D receptors (VDRs) are ubiquitous and drive the expression of hundreds of genes, the interest in vitamin D has tremendously grown and its role in different diseases has been extensively studied. Several investigations indicated that vitamin D action extends far beyond bone health and calcium metabolism, showing broad effects on a variety of critical illnesses, including cancer, infections, cardiovascular and autoimmune diseases. Epidemiological studies indicated that low circulating vitamin D levels inversely correlate with cutaneous manifestations and bone abnormalities, clinical hallmarks of neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant tumour predisposition syndrome causing significant pain and morbidity, for which limited treatment options are available. In this context, vitamin D or its analogues have been used to treat both skin and bone lesions in NF1 patients, alone or combined with other therapeutic agents. Here we provide an overview of vitamin D, its characteristic nutritional properties relevant for health benefits and its role in NF1 disorder. We focus on preclinical and clinical studies that demonstrated the clinical correlation between vitamin D status and NF1 disease, thus providing important insights into disease pathogenesis and new opportunities for targeted therapy.

Modulating effect of vitamin D3 on the mutagenicity and carcinogenicity of doxorubicin in Drosophila melanogaster and in silico studies

Vitamin D3 (VD3) deficiency increases DNA damage, while supplementation may exert a pro-oxidant activity, prevent viral infections and formation of tumors. The aim of this study was to investigate the mutagenicity and carcinogenicity of VD3 alone or in combination with doxorubicin (DXR) using the Somatic Mutation and Recombination Test and the Epithelial Tumor Test, both in Drosophila melanogaster. For better understanding of the molecular interactions of VD3 and receptors, in silico analysis were performed with molecular docking associated with molecular dynamics. Findings revealed that VD3 alone did not increase the frequency of mutant spots, but reduced the frequency of mutant spots when co-administered with DXR. In addition, VD3 did not alter the recombinogenic effect of DXR in both ST and HB crosses. VD3 alone did not increase the total frequency of tumor, but significantly reduced the total frequency of tumor when co-administered with DXR. Molecular modeling and molecular dynamics between calcitriol and Ecdysone Receptor (EcR) showed a stable interaction, indicating the possibility of signal transduction between VD3 and EcR. In conclusion, under these experimental conditions, VD3 has modulatory effects on the mutagenicity and carcinogenicity induced by DXR in somatic cells of D. melanogaster and exhibited satisfactory interactions with the EcR.

Independent and Interactive Influences of Environmental UVR, Vitamin D Levels, and Folate Variant MTHFD1-rs2236225 on Homocysteine Levels

Elevated homocysteine (Hcy) levels are a risk factor for vascular diseases. Recently, increases in ultraviolet radiation (UVR) have been linked to decreased Hcy levels. This relationship may be mediated by the status of UVR-responsive vitamins, vitamin D and folate, and/or genetic variants influencing their levels; however, this has yet to be examined. Therefore, the independent and interactive influences of environmental UVR, vitamin D and folate levels and related genetic variants on Hcy levels were examined in an elderly Australian cohort (n = 619). Red blood cell folate, 25-hydroxyvitamin D (25(OH)D), and plasma Hcy levels were determined, and genotyping for 21 folate and vitamin D-related variants was performed. Erythemal dose rate accumulated over six-weeks (6W-EDR) and four-months (4M-EDR) prior to clinics were calculated as a measure of environmental UVR. Multivariate analyses found interactions between 6W-EDR and 25(OH)D levels (pinteraction = 0.002), and 4M-EDR and MTHFD1-rs2236225 (pinteraction = 0.006) in predicting Hcy levels. The association between 6W-EDR and Hcy levels was found only in subjects within lower 25(OH)D quartiles (<33.26 ng/mL), with the association between 4M-EDR and Hcy occurring only in subjects carrying the MTHFD1-rs2236225 variant. 4M-EDR, 6W-EDR, and MTHFD1-rs2236225 were also independent predictors of Hcy. Findings highlight nutrient-environment and gene-environment interactions that could influence the risk of Hcy-related outcomes.

Distribution of variants in multiple vitamin D-related loci (DHCR7/NADSYN1, GC, CYP2R1, CYP11A1, CYP24A1, VDR, RXRα and RXRγ) vary between European, East-Asian and Sub-Saharan African-ancestry populations

BACKGROUND

The frequency of vitamin D-associated gene variants appear to reflect changes in long-term ultraviolet B radiation (UVB) environment, indicating interactions exist between the primary determinant of vitamin D status, UVB exposure and genetic disposition. Such interactions could have health implications, where UVB could modulate the impact of vitamin D genetic variants identified as disease risk factors. However, the current understanding of how vitamin D variants differ between populations from disparate UVB environments is limited, with previous work examining a small pool of variants and restricted populations only.

METHODS

Genotypic data for 46 variants within multiple vitamin D-related loci (DHCR7/NADSYN1, GC, CYP2R1, CYP11A1, CYP27A1, CYP24A1, VDR, RXRα and RXRγ) was collated from 60 sample sets (2633 subjects) with European, East Asian and Sub-Saharan African origin via the NCBI 1000 Genomes Browser and ALFRED (Allele Frequency Database), with the aim to examine for patterns in the distribution of vitamin D-associated variants across these geographic areas.

RESULTS

The frequency of all examined genetic variants differed between populations of European, East Asian and Sub-Saharan African ancestry. Changes in the distribution of variants in CYP2R1, CYP11A1, CYP24A1, RXRα and RXRγ genes between these populations are novel findings which have not been previously reported. The distribution of several variants reflected changes in the UVB environment of the population's ancestry. However, multiple variants displayed population-specific patterns in frequency that appears not to relate to UVB changes.

CONCLUSIONS

The reported population differences in vitamin D-related variants provides insight into the extent by which activity of the vitamin D system can differ between cohorts due to genetic variance, with potential consequences for future dietary recommendations and disease outcomes.

Toxicological evaluation of ergocalciferol, cholecalciferol, and their metabolites by a category approach

Predictive toxicology plays an integral role in determining the toxicological profiles of chemicals for safety assessment. Vitamin D is an essential vitamin for the regulation of calcium absorption and homeostasis, as well as the treatment and prevention of several diseases such as rickets and osteomalacia. According to European Medicines Agency (EMA) Guideline on setting health-based exposure limits for use in risk identification in the manufacturing of different medicinal products in shared facilities, permitted daily exposure (PDE) calculation for active pharmaceutical ingredients (APIs) should be done by the medicinal product producers. PDE calculation is mainly based on critical toxicological endpoints such as repeated dose toxicity, genotoxicity, carcinogenicity, developmental and reproductive toxicity, and hypersensitivity potential. During this procedure, critical toxicological endpoints data of an API can be used to predict the PDE of another API that has a similar chemical structure. In the present paper, human toxicological endpoints of vitamin D₂, D₃, and their metabolites were evaluated and afterwards the data gaps in the toxicological endpoints were filled by forming a category. The read-across was justified by the structural and metabolic similarities. Molecular similarity and mechanistic relevance were found to be substantial, resulting in low uncertainty. The untested vitamin D analogs within the category can be read across with confidence to complete the data gaps related to the human health endpoints.

The Relationship between Serum Vitamin D Levels with Allergic Rhinitis Incidence and Total Nasal Symptom Score in Allergic Rhinitis Patients

BACKGROUND

Allergic diseases and vitamin D deficiency were found to have a relationship. However, there was limited number of studies on the relationship between vitamin D with allergic rhinitis (AR) and total nasal symptom scores (TNSS), particularly in determining the cut-off points of serum vitamin D levels which correlated to AR.

AIM

As this particular study has never been conducted in Indonesia, the main objective of this study was to investigate this issue.

METHODS

The research was conducted at Dr Soetomo Hospital, Surabaya in January 2017. A group of 30 subjects were recruited using consecutive sampling. Levels of serum vitamin D were measured using electrochemiluminescence immunoassay (ECLIA) method while the total nasal symptom scores were obtained by accumulating all the nasal symptoms. Data of serum vitamin D levels and TNSS were analysed statistically with the Pearson correlation test.

RESULTS

It was found that the mean of serum 25(OH) vitamin D levels (9.13 ng/mL) of the AR group was significantly lower than the non-AR group (26.22 ng/mL) (P = 0.000). The vitamin D cut-off points which correlated to AR was about 12.83 ng/mL (sensitivity = 80%; specificity = 100%). A Pearson correlation test found a strong, negative correlation between vitamin D levels and TNSS (P = 0.000; r = -0.800).

CONCLUSION

There was a strong, negative correlation between serum vitamin D levels with AR and TNSS. The cut-off points of serum vitamin D levels correlated to AR were approximately12.83 ng/mL. Thus, further research needs to be conducted.

The Vitamin D⁻Folate Hypothesis as an Evolutionary Model for Skin Pigmentation: An Update and Integration of Current Ideas

Vitamin D is unique in being generated in our skin following ultraviolet radiation (UVR) exposure. Ongoing research into vitamin D must therefore always consider the influence of UVR on vitamin D processes. The close relationship between vitamin D and UVR forms the basis of the “vitamin D–folate hypothesis”, a popular theory for why human skin colour has evolved as an apparent adaption to UVR environments. Vitamin D and folate have disparate sensitivities to UVR; whilst vitamin D may be synthesised following UVR exposure, folate may be degraded. The vitamin D–folate hypothesis proposes that skin pigmentation has evolved as a balancing mechanism, maintaining levels of these vitamins. There are several alternative theories that counter the vitamin D–folate hypothesis. However, there is significant overlap between these theories and the now known actions of vitamin D and folate in the skin. The focus of this review is to present an update on the vitamin D–folate hypothesis by integrating these current theories and discussing new evidence that supports associations between vitamin D and folate genetics, UVR, and skin pigmentation. In light of recent human migrations and seasonality in disease, the need for ongoing research into potential UVR-responsive processes within the body is also discussed.

Hereditary vitamin D-resistant rickets in Lebanese patients: the p.R391S and p.H397P variants have different phenotypes

BACKGROUND

Hereditary vitamin D-resistant rickets (HVDRR) is an autosomal recessive disorder caused by mutations in the vitamin D receptor (VDR) gene. Variable phenotypes have been associated with these mutations, and some of these were linked to the effects they have on the interacting partners of VDR, mainly the retinoic X receptor (RXR).

METHODS

We examined four patients with HVDRR from three unrelated Lebanese families. All parents were consanguineous with normal phenotype. We used Sanger sequencing to identify mutations in the coding exons of VDR.

RESULTS

Two homozygous mutations (p.R391S and p.H397P), both in exon 9 of the VDR gene, were identified. Phenotype/genotype association was not possible even for the same mutation. Alopecia was seen only with the p.R391S mutation. Despite a comparable rachitic bone disease, the patients showed different responsiveness to large doses of alfacalcidol (1-α-hydroxy vitamin D3) supplementation.

CONCLUSIONS

This is the first report of VDR mutations in Lebanon with promising clinical outcomes despite the severity of the phenotypes.

Plasma Vitamin D Deficiency Is Associated With Poor Sleep Quality and Night-Time Eating at Mid-Pregnancy in Singapore

Plasma 25-hydroxyvitamin D (25OHD) deficiency, poor sleep quality, and night-time eating, have been independently associated with adverse pregnancy outcomes, but their inter-relationships are yet to be evaluated. We aimed to investigate the associations between maternal plasma 25OHD status and sleep quality and circadian eating patterns during pregnancy. Data on pregnant women (n = 890) from a prospective cohort (Growing Up in Singapore Towards healthy Outcomes) were analyzed. Plasma 25OHD concentration was measured, while the Pittsburgh sleep quality index (PSQI) and 24-h dietary recall were administered to women at 26-28 weeks' gestation. Plasma 25OHD status was defined as sufficient (>75 nmol/L), insufficient (50-75 nmol/L), or deficient (<50 nmol/L). Poor sleep quality was defined by a total global PSQI score >5. Predominantly day-time (pDT) and predominantly night-time (pNT) were defined according to consumption of greater proportion of calories (i.e., >50%) from 07:00-18:59 and from 19:00-06:59, respectively. After adjustment for confounders, women with plasma 25OHD deficiency had higher odds of poor sleep quality (odds ratio (OR) 3.49; 95% confidence interval (CI) 1.84-6.63) and pNT eating (OR: 1.85; 95% CI 1.00-3.41) than those who were 25OHD sufficient. Our findings show the association of maternal plasma 25OHD deficiency with poor sleep quality and pNT eating at mid-pregnancy.