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.

High-Dose Vitamin D For The Treatment Of COVID-19

IntroductionThe aim of this EUnetHTA (European Network for Health Technology Assessment) Rolling Collaborative Review on high dose vitamin D for the treatment of COVID-19 was to inform health policy at an early stage in the life cycle of therapies and to monitor ongoing studies in the format of a Living Document.MethodsThe systematic literature search was conducted in Medline, Pubmed, medRxiv, bioRxiv, arXivso, Cochrane COVID-19 Study Register, ClinicalTrials.gov, ISRCTN Registry, EU Clinical Trials Register. The first search was done in January 2021, and the last in November 2021. English and German randomized controlled studies (RCTs) investigating treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected individuals with high dose vitamin D2, D3 or their metabolites were included if examining mortality, length of hospital stay, viral burden, clinical progression, hospitalization rates, intensive care unit (ICU) admission, mechanical ventilation, quality of life or adverse events. Two reviewers independently screened search results and assessed risk of bias and certainty of evidence. One reviewer extracted study data, checked by another.ResultsOf the nine RCTs published to date, two investigate calcifediol, one calcitriol and six vitamin D3. All used different dosing regimens. Disease severity and proportion of vitamin D deficiency varied between studies. Calcifediol treated patients in one study required significantly less ICU admissions than untreated patients. Vitamin D3 in another study led to significantly more SARS-CoV-2 PCR-negative patients before day 21 than placebo. There were no other significant differences between groups. Twenty-five RCTs are ongoing, five of them with over 1,000 patients.ConclusionsThe current evidence is heterogenous regarding form and dosage of vitamin D, baseline disease severity and baseline vitamin D deficiency. There is currently no standardized/recommended level of what constitutes a (beneficial) "high dose”. Most results did not show significant differences between vitamin D treated groups and no vitamin D / placebo groups. Many of the studies are very small and certainty of evidence is predominantly low or very low.

Vitamin D supplementation and immune-related markers: an update from nutrigenetic and nutrigenomic studies

Vitamin D is both a nutrient and a neurologic hormone that plays a critical role in modulating immune responses. While low levels of vitamin D are associated with increased susceptibility to infections and immune-related disorders, vitamin D supplementation has demonstrated immunomodulatory effects that can be protective against various diseases and infections. Vitamin D receptor is expressed in immune cells that have the ability to synthesise the active vitamin D metabolite. Thus, vitamin D acts in an autocrine manner in a local immunologic milieu in fighting against infections. Nutrigenetics and nutrigenomics are the new disciplines of nutritional science that explore the interaction between nutrients and genes using distinct approaches to decipher the mechanisms by which nutrients can influence disease development. Though molecular and observational studies have proved the immunomodulatory effects of vitamin D, only very few studies have documented the molecular insights of vitamin D supplementation. Until recently, researchers have investigated only a few selected genes involved in the vitamin D metabolic pathway that may influence the response to vitamin D supplementation and possibly disease risk. This review summarises the impact of vitamin D supplementation on immune markers from nutrigenetics and nutrigenomics perspective based on evidence collected through a structured search using PubMed, EMBASE, Science Direct and Web of Science. The research gaps and shortcomings from the existing data and future research direction of vitamin D supplementation on various immune-related disorders are discussed.

Vitamin D supplementation to treat SARS-CoV-2 positive patients. Evidence from meta-analysis.

BACKGROUND: Vitamin D is a likely candidate for treatment as its immune modulating characteristics have effects on coronavirus disease 2019 (COVID-19) patients. It was sought herein, to summarize the studies published to date regarding the vitamin D supplementation to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive patients. METHODS: A systematic review and meta-analysis were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The primary outcome were 14-day and in-hospital mortality reported as an odds ratio (OR) with the associated 95% confidence interval (CI). RESULTS: Eight articles were included in the review with a combined total of 2,322 individual patients, 786 in the vitamin D supplementation group and 1,536 in the control group. The use of vitamin D compared to the group without vitamin D supplementation was associated with a lower 14-day mortality (18.8% vs. 31.3%, respectively; OR = 0.51; 95% CI: 0.12-2.19; p = 0.36), a lower in-hospital mortality (5.6% vs. 16.1%; OR = 0.56; 95% CI: 0.23-1.37; I2 = 74%; p = 0.20), the rarer intensive care unit admission (6.4% vs. 23.4%; OR = 0.19; 95% CI: 0.06-0.54; I2 = 77%; p = 0.002) as well as rarer mechanical ventilation (6.5% vs. 18.9%; OR = 0.36; 95% CI: 0.16-0.80; I2 = 0.48; p = 0.01). CONCLUSIONS: Vitamin D supplementation in SARS-CoV-2 positive patients has the potential to positively impact patients with both mild and severe symptoms. As several high-quality randomized control studies have demonstrated a benefit in hospital mortality, vitamin D should be considered a supplemental therapy of strong interest. Should vitamin D prove to reduce hospitalization rates and symptoms outside of the hospital setting, the cost and benefit to global pandemic mitigation efforts would be substantial.