The role of vitamin D in prevention and treatment of infection

SARS-CoV-2 positivity rates associated with circulating 25-hydroxyvitamin D levels

Until treatment and vaccine for coronavirus disease-2019 (COVID-19) becomes widely available, other methods of reducing infection rates should be explored. This study used a retrospective, observational analysis of deidentified tests performed at a national clinical laboratory to determine if circulating 25-hydroxyvitamin D (25(OH)D) levels are associated with severe acute respiratory disease coronavirus 2 (SARS-CoV-2) positivity rates. Over 190,000 patients from all 50 states with SARS-CoV-2 results performed mid-March through mid-June, 2020 and matching 25(OH)D results from the preceding 12 months were included. Residential zip code data was required to match with US Census data and perform analyses of race/ethnicity proportions and latitude. A total of 191,779 patients were included (median age, 54 years [interquartile range 40.4-64.7]; 68% female. The SARS-CoV-2 positivity rate was 9.3% (95% C.I. 9.2-9.5%) and the mean seasonally adjusted 25(OH)D was 31.7 (SD 11.7). The SARS-CoV-2 positivity rate was higher in the 39,190 patients with "deficient" 25(OH)D values (<20 ng/mL) (12.5%, 95% C.I. 12.2-12.8%) than in the 27,870 patients with "adequate" values (30-34 ng/mL) (8.1%, 95% C.I. 7.8-8.4%) and the 12,321 patients with values ≥55 ng/mL (5.9%, 95% C.I. 5.5-6.4%). The association between 25(OH)D levels and SARS-CoV-2 positivity was best fitted by the weighted second-order polynomial regression, which indicated strong correlation in the total population (R2 = 0.96) and in analyses stratified by all studied demographic factors. The association between lower SARS-CoV-2 positivity rates and higher circulating 25(OH)D levels remained significant in a multivariable logistic model adjusting for all included demographic factors (adjusted odds ratio 0.984 per ng/mL increment, 95% C.I. 0.983-0.986; p<0.001). SARS-CoV-2 positivity is strongly and inversely associated with circulating 25(OH)D levels, a relationship that persists across latitudes, races/ethnicities, both sexes, and age ranges. Our findings provide impetus to explore the role of vitamin D supplementation in reducing the risk for SARS-CoV-2 infection and COVID-19 disease.

Idiopathic TTP in the Middle East: Epidemiology and clinical outcomes in infection associated episodes

INTRODUCTION

Literature on epidemiology of thrombotic thrombocytopenic purpura (TTP) in the Middle East is scarce.

MATERIALS AND METHODS

We prospectively examined the association between infection and clinical outcomes in 44 patients with idiopathic TTP, with severely deficient ADAMTS13. We also investigated seasonality of the disease, hoping to better understand the epidemiology of idiopathic TTP.

RESULTS

Summer demonstrated significantly lower incidence for idiopathic TTP, compared with other seasons P = 0.0003. Fourteen patients had 15 episodes with a suspected concomitant infection. Five initial episodes were triggered by an infection (33.3 %), all presenting in winter, six episodes were associated with an exacerbation (40 %) and infection triggered a relapse in the other four episodes (26.7 %), with 2 episodes presenting in winter. TTP associated infections included: central line infection, urinary tract infection and post-operative infection. One patient had respiratory tract infection, on both his initial and relapsing episodes. Refractoriness to treatment was demonstrated in 4 patients (28.6 %) and it was associated with dental abscess (one patient), septic shock (one patient) and Mycoplasma pneumonia (2 patients). All 4 patients had markedly elevated CRP values with a median of 335 mg/L.

CONCLUSION

Most of the infection associated episodes developed in winter (77.8 %). In patients with idiopathic TTP refractory to conventional treatment, infection should be seriously considered as an additional contributing factor for their initial and /or recurrent episodes, particularly when CRP is markedly elevated.

Role of probiotics to combat viral infections with emphasis on COVID-19

Interspecies transmissions of viruses between animals and humans may result in unpredictable pathogenic potential and new transmissible diseases. This mechanism has recently been exemplified by the discovery of new pathogenic viruses, such as the novel severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) pandemic, Middle-East respiratory syndrome-coronavirus epidemic in Saudi Arabia, and the deadly outbreak of Ebola in West Africa. The. SARS-CoV-2 causes coronavirus disease-19 (COVID-19), which is having a massive global impact in terms of economic disruption, and, above all, human health. The disease is characterized by dry cough, fever, fatigue, myalgia, and dyspnea. Other symptoms include headache, sore throat, rhinorrhea, and gastrointestinal disorders. Pneumonia appears to be the most common and severe manifestation of the infection. Currently, there is no vaccine or specific drug for COVID-19. Further, the development of new antiviral requires a considerable length of time and effort for drug design and validation. Therefore, repurposing the use of natural compounds can provide alternatives and can support therapy against COVID-19. In this review, we comprehensively discuss the prophylactic and supportive therapeutic role of probiotics for the management of COVID-19. In addition, the unique role of probiotics to modulate the gut microbe and assert gut homeostasis and production of interferon as an antiviral mechanism is described. Further, the regulatory role of probiotics on gut-lung axis and mucosal immune system for the potential antiviral mechanisms is reviewed and discussed.Key points• Gut microbiota role in antiviral diseases• Factors influencing the antiviral mechanism• Probiotics and Covid-19.

Flavonoids Activation of the Transcription Factor Nrf2 as a Hypothesis Approach for the Prevention and Modulation of SARS-CoV-2 Infection Severity

The Nrf2-Keap1-ARE pathway is the principal regulator of antioxidant and phase II detoxification genes. Its activation increases the expression of antioxidant and cytoprotective proteins, protecting cells against infections. Nrf2 modulates virus-induced oxidative stress, ROS generation, and disease pathogenesis, which are vital in the viral life cycle. During respiratory viral infections, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an inflammatory process, and oxidative stress of the epithelium lining cells activate the transcription factor Nrf2, which protects cells from oxidative stress and inflammation. Nrf2 reduces angiotensin-converting enzyme 2 (ACE2) receptors expression in respiratory epithelial cells. SARS-CoV2 has a high affinity for ACE2 that works as receptors for coronavirus surface spike glycoprotein, facilitating viral entry. Disease severity may also be modulated by pre-existing conditions, such as impaired immune response, obesity, and age, where decreased level of Nrf2 is a common feature. Consequently, Nrf2 activators may increase Nrf2 levels and enhance antiviral mediators' expression, which could initiate an "antiviral state", priming cells against viral infection. Therefore, this hypothesis paper describes the use of flavonoid supplements combined with vitamin D3 to activate Nrf2, which may be a potential target to prevent and/or decrease SARS-CoV-2 infection severity, reducing oxidative stress and inflammation, enhancing innate immunity, and downregulating ACE2 receptors.

Immunologic Effects of Vitamin D on Human Health and Disease

Vitamin D is responsible for regulation of calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. It is also known as an immunomodulatory hormone. Experimental studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, exerts immunologic activities on multiple components of the innate and adaptive immune system as well as endothelial membrane stability. Association between low levels of serum 25-hydroxyvitamin D and increased risk of developing several immune-related diseases and disorders, including psoriasis, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, tuberculosis, sepsis, respiratory infection, and COVID-19, has been observed. Accordingly, a number of clinical trials aiming to determine the efficacy of administration of vitamin D and its metabolites for treatment of these diseases have been conducted with variable outcomes. Interestingly, recent evidence suggests that some individuals might benefit from vitamin D more or less than others as high inter-individual difference in broad gene expression in human peripheral blood mononuclear cells in response to vitamin D supplementation has been observed. Although it is still debatable what level of serum 25-hydroxyvitamin D is optimal, it is advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 30 ng/mL (75 nmol/L), and preferably at 40-60 ng/mL (100-150 nmol/L) to achieve the optimal overall health benefits of vitamin D.

Can Vitamin D and L-Cysteine Co-Supplementation Reduce 25(OH)-Vitamin D Deficiency and the Mortality Associated with COVID-19 in African Americans?

Early reports indicate an association between the severity of the COVID-19 infection and the widespread 25-hydroxy vitamin D deficiency known to exist in populations around the world. Vitamin D deficiency is extremely common among African American (AA) communities, where the COVID-19 infection rate is three-fold higher, and the mortality rate nearly six-fold higher, compared with rates in predominantly white communities. COVID-19 infection primarily affects the lungs and airways. Previous reports have linked 25-hydroxy vitamin D deficiency with subclinical interstitial lung disease. AA are at risk for lower cellular glutathione (GSH) levels, and GSH deficiency epigenetically impairs VD biosynthesis pathway genes. Compared with vitamin D alone, co-supplementation of vitamin D and L-cysteine (a GSH precursor) showed a better efficacy in improving levels of GSH and VD-regulatory genes at the cellular/tissue level, increasing 25(OH) vitamin D levels, and reducing inflammation biomarkers in the blood in mice studies. We propose that randomized clinical trials are needed to examine the potential of co-supplementation with anti-inflammatory antioxidants, vitamin D and L-cysteine in correcting the 25(OH)VD deficiency and preventing the 'cytokine storm,' one of the most severe consequences of infection with COVID-19, thereby preventing the adverse clinical effects of COVID-19 infection in the vulnerable AA population.

Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005-2016 NHANES

A well-functioning immune system is essential for human health and well-being. Micronutrients such as vitamins A, C, D, E, and zinc have several functions throughout the immune system, yet inadequate nutrient intakes are pervasive in the US population. A large body of research shows that nutrient inadequacies can impair immune function and weaken the immune response. Here, we present a new analysis of micronutrient usual intake estimates based on nationally representative data in 26,282 adults (>19 years) from the 2005-2016 National Health and Nutrition Examination Surveys (NHANES). Overall, the prevalence of inadequacy (% of population below estimated average requirement [EAR]) in four out of five key immune nutrients is substantial. Specifically, 45% of the U.S. population had a prevalence of inadequacy for vitamin A, 46% for vitamin C, 95% for vitamin D, 84% for vitamin E, and 15% for zinc. Dietary supplements can help address nutrient inadequacy for these immune-support nutrients, demonstrated by a lower prevalence of individuals below the EAR. Given the long-term presence and widening of nutrient gaps in the U.S.-specifically in critical nutrients that support immune health-public health measures should adopt guidelines to ensure an adequate intake of these micronutrients. Future research is needed to better understand the interactions and complexities of multiple nutrient shortfalls on immune health and assess and identify optimal levels of intake in at-risk populations.

Vitamin D status and the immune assessment in 22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is characterized by a heterogeneous phenotype, including alterations in phospho-calcium metabolism and immunodeficiency. We analyzed vitamin D status and the immune assessment, focusing on T cell subpopulations and dendritic cells (DCs) in a cohort of 17 pediatric 22q11.2DS patients and 17 age-matched healthy subjects. As antigen-presenting cells, DCs are the main target of vitamin D, promoting a tolerogenic T cell response. Patients were subdivided into three groups according to the parameters of phospho-calcium metabolism and serum levels of 25OHD: normal values, vitamin D deficiency and hypoparathyroidism. Different degrees of T cell deficiency, ranging from normal to partial T cell numbers, were observed in the cohort of patients. The group with vitamin D deficiency showed a significant reduction of naive T cells and a significant increase of central memory T cells compared to controls. In this group the number of circulating DCs was significantly reduced. DC decrease affected both myeloid and plasmacytoid DC subsets (mDCs and pDCs), with the most relevant reduction involving pDCs. A direct correlation between 25OHD levels and recent thymic emigrant (RTE) and DC number was identified. Despite the limited cohort analyzed, our results show that deficiency of the pDC subset in patients with 22q11.2DS may be included among the causative factors of the progressive increase of risk of autoimmune diseases in these patients. As most patients suffer from increased susceptibility to infections and heightened prevalence of autoimmune disorders, we suggest a potential role of vitamin D supplementation in preventing autoimmune or proinflammatory diseases in 22q11.2DS.

Vitamin D alleviates acute graft-versus-host disease through promoting the generation of Foxp3+ T cells

Background

Acute graft-versus-host disease (aGVHD) is a medical complication which may result in significant morbidity and mortality after transplantation. The aim of this study investigated the therapeutic effect and underlying mechanism of 1,25-dihydroxyvitamin D3 (1α,25(OH)₂D₃) in the treatment of aGVHD.

Method

An aGVHD model was built by transferring splenocytes of B6 mice into B6D2F1 mice. 1α,25(OH)₂D₃ was added to evaluate the protective function to aGVHD; the phenotype and cytokine expression profile of spleen cells from the aGVHD model were determined using flow cytometry 2 weeks after the model is established.

Result

Administration of 1α,25(OH)₂D₃ significantly slowed aGVHD progression and improved survival of B6D2F1 recipients of grafted B6 splenocytes. 1α,25(OH)₂D₃ treatment also resulted in an increased number of CD4⁺Foxp3⁺ regulatory T cells (Tregs) but decreased the number of CD4⁺IL-4⁺ cells. In vitro analysis demonstrated that 1α,25(OH)₂D₃ directly increased forkhead box P3 (Foxp3) and IL-10 expression and enhanced the function of induced Tregs (iTregs).

Conclusions

This analysis indicated that the effect of 1α,25(OH)₂D₃ is mediated in part by improving the number of Tregs. 1α,25(OH)₂D₃ administration thus represents a viable approach for treating aGVHD.

The association between vitamin D deficiency and community-acquired pneumonia: A meta-analysis of observational studies

Emerging evidence has shown that vitamin D deficiency may be related with community-acquired pneumonia (CAP), but individually published studies showed inconclusive results. The aim of this study was to quantitatively summarize the association between vitamin D and the CAP.We conducted this meta-analysis though a systematic literature search of PubMed, Medline, and EMBASE up to 31 September 2018 with the following keywords 'vitamin D' or 'cholecalciferol' or '25-hydroxyvitamin D' or '25(OH)D' in combination with 'community-acquired pneumonia' or 'CAP' or 'pneumonia' with no limitations. This meta-analysis was performed following the guidelines of Meta-analysis of Observational Studies in Epidemiology. The association between vitamin D levels and CAP were measured as odds ratio (OR) and weighted mean difference (WMD). Results were combined using a random-effect or a fix-effect meta-analysis, and sensitivity analyses were conducted to explore potential factors.Eight observational studies involving 20,966 subjects were included. In this meta-analysis, CAP patients with vitamin D deficiency (serum 25(OH)D levels <20 ng/mL) experienced a significantly increased risk of CAP (odds ratio (OR) = 1.64, 95% confidence intervals (CI): 1.00, 2.67), and an obvious decrease of -5.63 ng/mL (95% CI: -9.11, -2.14) in serum vitamin D was demonstrated in CAP patients. Sensitivity analysis showed that exclusion of any single study did not materially alter the overall combined effect.The evidence from this meta-analysis indicates an association between vitamin D deficiency and an increased risk of CAP patients. However, well-designed trails are required to determine the explicit effect of vitamin D supplementation.

An Innovative Technique in Local Antibiotic Delivery Method in Open Infected Wounds of the Musculoskeletal System

Bone and soft tissue infections are difficult problems in orthopedic surgery. Infections resulting in chronic osteomyelitis if established are difficult to eradicate. The delivery of local antibiotics for the treatment of open infected wounds of the musculo skeletal system is a more logical approach to treat these infections. Antibiotics given systemically are unable to achieve minimum inhibitory concentration in areas of infected wounds which are ischemic or relatively avascular. And also these antibiotics given over a prolonged period lead to significant toxicity and side effects and emergence of resistant bacteria. The author has been treating difficult cases of infected wounds sustained in road accidents, wounds (diabetic ulcers) in Diabetes Mellitus with necrotizing fasciitis and post operative infections with discharging sinuses with infected implants inside by his own innovative method of antibiotic delivery. The infected open wounds have been treated by application of Vitamin D3 granules impregnated with Tobramycin or Tobramycin and Vancomycin combined. All the patients responded successfully to this novel method of treatment which is extremely simple, effective, low cost, without any complications or side effects and has shown excellent results. Not only the Vitamin D₃ granules act as a carrier of the antibiotic locally but also have properties of boosting immunity, and promote tissue healing. It also produces an antibiotic like substance Cathelicidin which kills bacteria and promotes growth of the bone and restores the bone mineral density.

Evolutionary Perspective in Rickets and Vitamin D

Modern lifestyle limits our exposure to sunlight, which photosynthesizes vitamin D in the skin, and the incidence of nutritional rickets has been resurging. Vitamin D is one of the first hormones; it is photosynthesized in all organism from the phytoplankton to mammals. A selective sweep of the promoter of the vitamin D receptor (VDR) happened as soon as Homo sapiens migrated out of Africa; it co-adapted with skin color genes to provide adaptation to latitudes and the levels of exposure to ultraviolet (UV)B radiation along the route out of Africa. Exposure to UVB radiation balances the need for vitamin D photosynthesis and degradation of folic acid by UVB radiation. Skin color follows a latitude distribution: the darkest populations dwell in the tropical belt; and the fair-skinned populations inhabit the northern countries. Due to their greater need for calcium during their reproductive life, the skin color of women is lighter- than that of men. Vitamin D is essential for mineral homeostasis and has a wide variety of non-skeletal functions, of which the most important for natural selection is a regulatory function in the innate immune system. In the human fossil record, vitamin D deficiency coincided with bone tuberculosis. About 6,000 years ago, a diet which included cow's milk provided Neolithic humans with twice as much calcium and was more alkaline than that of its Paleolithic predecessors. Adiposity is negatively associated with the vitamin D status and obese individuals require 2-3 times more vitamin D than non-obese individuals to normalize circulating 25OHD levels. In an era of an obesity epidemic, we need more research to determine whether adiposity should be considered when determining the dietary requirements for vitamin D and calcium and the optimal serum 25OHD levels.

Prevalence of low bone mass and changes in vitamin D levels in human immunodeficiency virus-infected adults unexposed to antiretrovirals

INTRODUCTION

The prevalence of low bone mass is 3 times higher in people living with human immunodeficiency virus (PLWH) and using antiretrovirals than in the HIV-unaffected population. Changes in vitamin D levels is one of the factors associated with decreased bone mass. The objective of this study is to evaluate the low bone mass and altered vitamin D levels in PLWH who have not been exposed to antiretrovirals.

METHODS

A cross-sectional study was carried out with HIV-infected individuals between the ages of 18 and 55 years immediately prior to the start of antiretroviral therapy in a specialized reference center focusing on infectious and parasitic diseases. Results of clinical examination (patient's weight, height, blood pressure, and clinical history), laboratory tests, and X-ray absorptiometry, were collected.

RESULTS

Sixty patients were included, with a mean age of 34 years. Nine (16.7%) patients presented with low bone mass and 4 (7.1%) patients showed low total femur BMD. Analysis revealed that 23.3% and 36.7% of the patients had deficient and insufficient levels of 25-hydroxyvitamin D3, respectively.

CONCLUSIONS

Our study population presented with compromised bone health and with low bone mineral density and 25-(OH)-vitamin D levels.

Vitamin D fortification of foods and prospective health outcomes

Vitamin D is essential for bone health and has significant roles in non-skeletal health and organ function. Dermal synthesis through exposure to ultraviolet B light is the major natural source of vitamin D, while only a small portion of the necessary amount can be acquired by a diet without fortified foods. In recent years, vitamin D deficiency as a result of lifestyles with inadequate sun exposure, has received increased attention due to its association with the increased risk of serious chronic diseases. This review summarizes our current understanding of food fortification strategies with vitamin D and the resulting health impact. Conventional and biotechnological approaches can be used for the production of new and novel vitamin D rich or vitamin D fortified foods. The availability of a wider range of every-day consumed fortified foods as part of a "Daily D" public health policy can contribute to the improvement of vitamin D status and to prevention of vitamin D deficiency.

Influence of Vitamin D Deficiency on Progression of Experimental Otitis Media in Rats

BACKGROUND

Vitamin D plays an important role in the immune response against infection. The purpose of the present study was to investigate the influence of vitamin D deficiency on the progression of otitis media (OM) using an experimental rat model.

METHODS

Four-week-old male Sprague-Dawley rats (n=72) were divided into two groups based on their diet: a control diet group (n=36) and a vitamin D-deficient diet group (n=36). After 8 weeks of diet, experimental OM was induced by inoculation of non-typeable Haemophilus influenzae in the middle ear cavity. The rats were evaluated with otomicroscopy to determine the inflammation in the middle ear mucosa on days 1, 2, 4, 7, and 14 post-inoculation. Bullae from sacrificed rats were collected and analyzed histologically.

RESULTS

The middle ear mucosa from rats with vitamin D deficiency showed a significantly higher thickness than that of controls during the course of OM. The maximum mucosal thickness was 56.0±9.1 μm in the vitamin D deficiency group, and 43.9±9.8 μm in the control group, although there was no significant difference in the tympanic membrane score between the two groups evaluated with otomicroscopy. An immunohistochemical study showed increased expression of interleukin 6 (IL-6) and tumor necrosis factor α in rats manifesting vitamin D deficiency and decreased expression of IL-10 compared with controls.

CONCLUSION

Our results showed that vitamin D deficiency may exacerbate the pathophysiological changes of OM via altered cytokine production. Therefore, maintaining vitamin D status in the optimal range may be beneficial for proper management of OM.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Clinical Management of Pediatric Acute-Onset Neuropsychiatric Syndrome: Part III-Treatment and Prevention of Infections

Objectives: Pediatric acute-onset neuropsychiatric syndrome (PANS) and its subset, pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS), are emerging autoimmune encephalopathies of childhood. Management guidelines are needed. This article, from the PANS/PANDAS Consortium, presents a consensus management guideline for the infection components. Accompanying papers from the Consortium discuss psychiatric and immunomodulatory management. Methods: Literature was reviewed and integrated with the clinical experience of the authors to provide a set of practical guidelines. This article was submitted to all members of the PANS/PANDAS Consortium, and their additional comments were added. Results: The relationships between PANS and infections are reviewed. An approach to the retrospective diagnosis of group A streptococcal infection for an operational definition of PANDAS is proposed. An initial course of anti-streptococcal treatment is proposed for all newly diagnosed PANS cases. Chronic secondary antimicrobial prophylaxis is suggested for children with PANDAS who have severe neuropsychiatric symptoms or recurrent group A Streptococcus-associated exacerbations. Guidelines for children with non-streptococcal PANS include vigilance for streptococcal pharyngitis or dermatitis in the patient and close contacts. All patients with PANS or PANDAS should also be closely monitored for other intercurrent infections, including sinusitis and influenza. Intercurrent infections should be diagnosed and treated promptly according to current standard guidelines. A guideline for the assessment of infection at initial onset or during neuropsychiatric exacerbations is also presented. Standard immunizations and attention to vitamin D are encouraged. Data indicating limited utility of adenotonsillectomy and probiotics are presented. Conclusion: A working guideline for the management of infection issues in PANS and PANDAS, based on literature and expert opinion, is provided.

Therapeutic effect of vitamin D in acute lower respiratory infection: A randomized controlled trial

OBJECTIVES

To study the effect of vitamin D supplementation on the outcome of acute lower respiratory infection in hospitalized children.

STUDY DESIGN

This is an open label parallel group randomized trial. Total of 154 children aged 2 mo-5 yrs (mean age 13 mo) admitted with acute lower respiratory infection (ALRI) were randomized to receive standard care therapy alone or standard care therapy for the respiratory infection along with a single oral dose of 100,000 IU of vitamin D3. Serum 25(OH)D levels were measured at admission in all the children and 72 h after administration of vitamin D in the supplemented group. Primary outcome measured was the duration of hospital stay. Secondary outcomes measured were mortality, incidence of complications, admission to PICU and recurrence of respiratory infections within 90 days of discharge. Primary outcome was compared using Mann Whitney U test and secondary outcomes were compared using chi-square or Fischer's exact test.

RESULTS

Baseline characteristics were comparable between the two groups. There was no statistically significant difference in the primary outcome (Median duration of hospital stay in both the groups) and also in secondary outcomes (mortality, PICU admission, complications and recurrence of respiratory infections within 90 days of discharge).

CONCLUSION

Single oral dose of 100,000 IU of vitamin D₃ did not lead to reduction in duration of hospital stay, mortality, PICU admission or complications related to ALRI when compared to standard therapy alone in under five children hospitalized with ALRI but was able to achieve serum vitamin D sufficiency within 72 h of administration. Registered under clinical trial Registry of India Identifier no: CTRI/2014/09/005032.

Low cord-serum 25-hydroxyvitamin D levels are associated with poor lung function performance and increased respiratory infection in infancy

Background

Perinatal vitamin D deficiency is associated with a higher risk of wheezing in childhood. However, the relationship between vitamin D levels and lung function in infancy has not been investigated. The aim of this study was to investigate the impact of perinatal vitamin D levels on respiratory function and disease outcome in infancy.

Materials and methods

Full-term infants without any chronic diseases or major anomalies were enrolled in the Prediction of Allergies in Taiwanese Children cohort study. Maternal and cord blood were collected for determining the 25(OH)D level. Questionnaires were recorded at birth and 6 months of age. Infant lung function, including tidal breathing analysis, respiratory mechanics, and forced tidal expiration, was tested at 6 months of age.

Results

A total of 122 mother—infant pairs were enrolled in this study, and 71 infants underwent lung function testing at 6 months of age. 25(OH)D levels in maternal and cord serum were highly correlated (r² = 0.457, p < 0.0001). Infants with lower cord serum 25(OH)D levels (< 13.7 ng/ml) had higher resistance of respiratory system (p < 0.01) and a higher risk of a respiratory tract infection before the age of 6 months (p < 0.01).

Conclusion

Although a high correlation was found between maternal and cord vitamin D levels, the effect on respiratory outcome was different. Our study is the first to show that low cord 25(OH)D levels significantly relationship with poorer lung function performance and higher likelihood of a respiratory tract infection before 6 months of age.

Vitamin D supplementation for preventing infections in children under five years of age

BACKGROUND

Vitamin D is a micronutrient important for bone growth and immune function. Deficiency can lead to rickets and has been linked to various infections, including respiratory infections. The evidence on the effects of supplementation on infections in children has not been assessed systematically.

OBJECTIVES

To evaluate the role of vitamin D supplementation in preventing pneumonia, tuberculosis (TB), diarrhoea, and malaria in children under five years of age. This includes high-, middle-, and low-income countries.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library, MEDLINE, EMBASE, LILACS, the WHO International Clinical Trials Registry Platform (ICTRP; http://www.who.int/ictrp/en/) , ClinicalTrials.gov and the ISRCTN registry (http://www.isrctn.com/) up to 16 June 2016.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated preventive supplementation of vitamin D (versus placebo or no intervention) in children under five years of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts, extracted the data, and assessed the risk of bias of included trials.

MAIN RESULTS

Four trials met the inclusion criteria, with a total of 3198 children under five years of age, and were conducted in Afghanistan, Spain, and the USA. Prevalence of vitamin D deficiency varied widely in these populations (range: 73.1% in Afghanistan, 10 to 12% in USA, and 6.2% in Spain). The included trials evaluated mortality (two trials), pneumonia incidence (two trials), diarrhoea incidence (two trials), hospitalization (two trials), and mean serum vitamin D concentrations (four trials).We do not know whether vitamin D supplementation impacts on all-cause mortality because this outcome was underpowered due to few events (risk ratio (RR) 1.43, 95% confidence interval (CI) 0.54 to 3.74; one trial, 3046 participants, low quality evidence).For pneumonia, episodes of 'radiologically confirmed' first or only episode of pneumonia were little different in the supplemented and unsupplemented group (Rate Ratio: 1.06, 95% confidence interval (CI) 0.89 to 1.26; two trials, 3134 participants, moderate quality evidence), and similarly for children with confirmed or unconfirmed pneumonia (RR 0.95, 95% CI 0.87 to 1.04; one trial, 3046 participants). In these two trials there were no obvious differences between supplemented and unsupplemented children regarding episodes of diarrhoea.In the single large trial from Afghanistan, the trial authors reported that vitamin D supplementation was associated with an increase in repeat episodes of pneumonia confirmed by chest radiograph (RR 1.69, 95% CI 1.28 to 2.21; one trial, 3046 participants), but not reflected in the outcome of confirmed or unconfirmed pneumonia (RR 1.06, 95% CI 1.00 to 1.13; one trial, 3046 participants).For hospital admission measured in one small trial, there was no difference detected (RR 0.86, 95% CI 0.20 to 3.62; one trial, 88 participants; very low quality evidence).The mean serum vitamin D concentrations were higher in supplemented compared to unsupplemented children at the end of supplementation (MD 7.72 ng/mL, 95% CI 0.50 to 14.93; four trials, 266 participants, low quality evidence). These results were driven primarily by two smaller trials with large magnitudes of effect. In the other two bigger trials, serum vitamin D concentrations were elevated in the intervention group for most of the trial duration but not at the end of supplementation. This may be due to time elapsed at measurement from the last dose, incomplete compliance, or increased need of vitamin D with infant age.We did not find any trial that reported on the incidence of TB, malaria or febrile illness, duration of pneumonia, duration of diarrhoea, severity of infection, and cause-specific mortality (due to TB, diarrhoea, or malaria).

AUTHORS' CONCLUSIONS

Evidence from one large trial did not demonstrate benefit of vitamin D supplementation on the incidence of pneumonia or diarrhoea in children under five years. To our knowledge, trials that evaluated supplementation for preventing other infections, including TB and malaria, have not been performed.

LL-37 but Not 25-Hydroxy-Vitamin D Serum Level Correlates with Healing of Venous Leg Ulcers

Human cathelicidin, LL-37, is small antimicrobial peptide, which reveals also some immunomodulatory and proangiogenic properties and, therefore, may promote wound healing. The expression of LL-37 is controlled by various factors, including vitamin D. Thus, any disturbances in vitamin D level may influence LL-37 production and, possibly, affect wound healing. Since deficiency of vitamin D was identified as a common problem in the population, this proof of concept study aimed to verify the relationship between serum levels of LL-37, vitamin D, and healing rate of venous leg ulcers. The study involved small group (n = 19) of patients with venous leg ulcers. Apart from non-venous ulcer aethiology, compression intolerance, active vein thrombosis, and wound infection, the exclusion criteria concerned also kidney insufficiency. The results of the analysis of wound healing rates were correlated with patients' serum levels of 25(OH) vitamin D and LL-37. In addition, serum levels of pro-inflammatory cytokines (IL-6, IL-8, and TNF) were analyzed. We have found strong association between serum concentrations of LL-37 and the healing rates in patients with leg ulcers. Despite the fact that 25(OH) vitamin D levels in all patients were below the normal range, they did not show any correlation with healing rates. Furthermore, no association was observed between serum levels of 25(OH) vitamin D and LL-37. No significant correlation between tested pro-inflammatory cytokines and healing rate, LL-37, or 25(OH) vitamin D levels was also observed. Regardless of small study group, our results suggest that the assessment of serum concentration of LL-37, but not 25-hydroxy vitamin D, may help in predicting the wound healing efficacy. Moreover, this assessment may be useful in pre-selection of patients, which could benefit from local treatment with exogenous LL-37.

Klokwerk + study protocol: An observational study to the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects

BACKGROUND

Night-shift work may cause severe disturbances in the worker's circadian rhythm, which has been associated with the onset of health problems and diseases. As a substantial part of the workforce is exposed to night-shift work, harmful aspects of night-shift work should not be overlooked. The aim of the Klokwerk + study is to study the effects of night-shift work on body weight and infection susceptibility and the mechanisms underlying these health effects. First, we will study the relation between night-shift work exposure and body weight and between night-shift work exposure and infection susceptibility. Second, we will examine the mechanisms linking night-shift work exposure to body weight and infection susceptibility, with a specific focus on sleep, physical activity, diet, light exposure, vitamin D level, and immunological factors. Lastly, we will focus on the identification of biomarkers for chronic circadian disturbance associated with night-shift work.

METHODS/DESIGN

The design of this study is a prospective observational cohort study consisting of 1,960 health care workers aged 18-65 years. The study population will consist of a group of night-shift workers and an equally sized group of non-night-shift workers. During the study, there will be two measurement periods. As one of the main outcomes of this study is infection susceptibility, the measurement periods will take place at approximately the first (September/October) (T0) and the last month (April/May) (T1, after 6 months) of the flu season. The measurements will consist of questionnaires, anthropometric measurements, a smartphone application to determine infection susceptibility, food diaries, actigraphy, light sensors, and blood sample analyses.

DISCUSSION

The Klokwerk + study will contribute to the current need for high-quality data on the health effects of night-shift work and its underlying behavioral and physiological mechanisms. The findings can be the starting point for the development of interventions that prevent negative health effects caused by night-shift work. In addition, the identification of biomarkers indicative of loss of homeostasis due to circadian disturbance may be an important asset in monitoring the effects of such interventions.

Regulation of Dendritic Cell Function by Vitamin D

Studies over the last two decades have revealed profound immunomodulatory aspects of vitamin D on various aspects of the immune system. This review will provide an overview of Vitamin D metabolism, a description of dendritic cell subsets, and highlight recent advances on the effects of vitamin D on dendritic cell function, maturation, cytokine production and antigen presentation. The active form of vitamin D, 1,25(OH)₂D₃, has important immunoregulatory and anti-inflammatory effects. Specifically, the 1,25(OH)₂D₃-Vitamin D₃ complex can affect the maturation and migration of many dendritic cell subsets, conferring a special immunoregulatory role as well as tolerogenic properties affecting cytokine and chemokine production. Furthermore, there have been many recent studies demonstrating the effects of Vitamin D on allergic disease and autoimmunity. A clear understanding of the effects of the various forms of Vitamin D will provide new opportunities to improve human health.

"Let there be light": the role of vitamin D in the immune response to vaccines

Vitamin D's non-skeletal actions, including immunomodulatory role, have been increasingly recognized. Of significance, many immune cells are able to synthesize a biologically active form of vitamin D from circulating 25-hydroxyvitamin D with subsequent intracrine actions, and the vitamin D receptor is broadly distributed. In this review, we discuss vitamin D's potent role in innate and adaptive immune responses and published studies evaluating the impact of serum vitamin D, vitamin D gene pathway polymorphisms or empiric vitamin D supplementation on vaccine immunogenicity. We highlight existing knowledge gaps and propose the steps needed to advance the science and answer the question of whether vitamin D may prove valuable as a vaccine adjuvant for certain vaccines against infectious diseases.

Vitamin D supplementation for the prevention of childhood acute respiratory infections: a systematic review of randomised controlled trials

Results from recent trials assessing the effect of vitamin D supplementation on the prevention of childhood acute respiratory infections (ARI) have been inconsistent. In the present study, we determined whether vitamin D supplementation prevents ARI in healthy children and repeated infections in children with previous ARI. We conducted a systematic literature search using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. The search included only randomised controlled clinical trials (RCT) comparing vitamin D supplementation with either placebo or no intervention in children younger than 18 years of age. We identified seven RCT and found that the summary estimates were not statistically significantly associated with a reduction in the risk of ARI (relative risk (RR) 0·79, 95% CI 0·55, 1·13), all-cause mortality (RR 1·18, 95% CI 0·71, 1·94), or the rate of hospital admission due to respiratory infection in healthy children (RR 0·95, 95% CI 0·72, 1·26). However, in children previously diagnosed with asthma, vitamin D supplementation resulted in a 74% reduction in the risk of asthma exacerbation (RR 0·26, 95% CI 0·11, 0·59; test of heterogeneity, I 2= 0·0%). Our findings indicate a lack of evidence supporting the routine use of vitamin D supplementation for the prevention of ARI in healthy children; however, they suggest that such supplementation may benefit children previously diagnosed with asthma. Due to the heterogeneity of the included studies and possible publication biases related to this field, these results should be interpreted with caution.

A review of nutrient treatments for paediatric depression

Paediatric depression is estimated to affect 15-20% of youths prior to adulthood and is associated with significant social, educational and physical impairment. Current treatments comprise moderately efficacious psychological therapies and pharmaceutical antidepressants. However, nutritional therapies are also available and are regularly sought by people with depressive illnesses and parents of depressed youths. In this narrative review, studies examining the antidepressant effects of individual nutritional supplements in child and adolescent populations are appraised. Epidemiological studies examining the relationship between nutritional status and paediatric depression, or depressive symptoms are also reviewed. Nutrients covered in this article include: omega-3 polyunsaturated fatty acids, s-adenosylmethionine, vitamin C, vitamin D, zinc, iron and B-vitamins. Although several of these nutrients present as promising treatments for paediatric depression, there is a lack of high-quality studies examining the antidepressant effects of all the aforementioned ingredients. Before nutritional treatments are accepted as validated treatments for paediatric depression, further high-quality studies are required.

Low Vitamin D and High Fibroblast Growth Factor 23 Serum Levels Associate with Infectious and Cardiac Deaths in the HEMO Study

Longitudinal studies testing the relationship between repeated measures of vitamin D or fibroblast growth factor 23 (FGF23) and infectious and cardiac hospitalizations and death in hemodialysis patients have not been reported. We examined the association between yearly 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and FGF23 serum levels and various clinical outcomes using time-dependent Cox regression models with repeated yearly measures and fixed-covariate Cox models with only baseline values after controlling for important clinical covariates in the HEMO study. During a median follow-up of 3 years, 582 of the 1340 participants died, and 499 and 514 participants had a hospitalization or death attributed to infectious and cardiac causes, respectively. Patients in the highest 25(OH)D quartile had the lowest risk of infectious events (hazard ratio [HR] 0.66 versus the lowest quartile; 95% confidence interval [95% CI], 0.49-0.89), cardiac events (HR, 0.71; 95% CI, 0.53-0.96), and all-cause mortality (HR, 0.46; 95% CI, 0.34-0.62) in time-dependent analyses. No significant associations of 1,25(OH)2D with clinical outcomes were observed in time-dependent or fixed-covariate Cox models. In contrast, the highest FGF23 quartile was associated with a higher risk of infectious events (HR, 1.57 versus the lowest quartile; 95% CI, 1.13-2.18), cardiac events (HR, 1.49; 95% CI, 1.06-2.08), and all-cause mortality (HR, 1.50; 95% CI, 1.07-2.12) in fixed-covariate Cox models. The addition of inflammation markers into the statistical models did not attenuate these associations. Thus, disordered mineral metabolism may affect outcomes in chronic hemodialysis patients.

Can we translate vitamin D immunomodulating effect on innate and adaptive immunity to vaccine response?

Vitamin D (VitD), which is well known for its classic role in the maintenance of bone mineral density, has now become increasingly studied for its extra-skeletal roles. It has an important influence on the body’s immune system and modulates both innate and adaptive immunity and regulates the inflammatory cascade. In this review our aim was to describe how VitD might influence immune responsiveness and its potential modulating role in vaccine immunogenicity. In the first instance, we consider the literature that may provide molecular and genetic support to the idea that VitD status may be related to innate and/or adaptive immune response with a particular focus on vaccine immunogenicity and then discuss observational studies and controlled trials of VitD supplementation conducted in humans. Finally, we conclude with some knowledge gaps surrounding VitD and vaccine response, and that it is still premature to recommend “booster” of VitD at vaccination time to enhance vaccine response.

Innate immune modulation in chronic obstructive pulmonary disease: moving closer toward vitamin D therapy

Chronic obstructive pulmonary disease (COPD) is one of the most common respiratory diseases and a major cause of morbidity and mortality worldwide. Disturbed innate immune processes characterize the pathogenesis of COPD. Vitamin D deficiency is very common in COPD patients and has been associated with disease severity. Interestingly, mechanistic evidence from animal and in vitro studies has demonstrated important innate immunomodulatory functions of vitamin D, including anti-inflammatory, antioxidative, and antimicrobial functions. This review discusses in detail how the innate immunomodulatory functions of vitamin D may have therapeutic potential in COPD patients. The remaining challenges associated with vitamin D therapy in COPD patients are also discussed.

The impact of vitamin D on the innate immune response to uropathogenic Escherichia coli during pregnancy

Urinary tract infections are highly common during pregnancy, and can cause serious complications for the mother and baby. Vitamin D, predominantly obtained from the sunlight, is known to have an effect on the urothelium, with immunomodulatory capacity against Escherichia coli infection. However, its influence at this site remains to be further explored. This study therefore investigated its impact during pregnancy in a population of women who have the possibility of adequate year-round sun exposure. Serum from pregnant Ugandan women (n = 32) in each trimester of pregnancy, from women after delivery (n = 29) and from never-pregnant controls (n = 25) was collected. 25-Hydroxyvitamin D (25-OHD), cathelicidin LL-37, human β-defensin 2, interleukin (IL)-8 and soluble CD14 serum concentrations were measured by chemiluminescence immunoassay or ELISA. The ability of serum to inhibit E. coli growth was tested. The immunomodulatory capacities of these serum samples and 1,25-dihydroxyvitamin D3 were investigated in urothelial cells. Increases in 25-OHD and LL-37 levels were observed as pregnancy progressed, peaking in the third trimester. Serum 25-OHD levels were higher in multigravidae than in primigravidae, and correlated positively with maternal age. IL-8 levels were lower in the third trimester than in the first trimester, increased after delivery, but remained below those of never-pregnant women. Similarly, soluble CD14 concentrations increased after delivery. As gestation advanced, serum had an increased capacity to inhibit E. coli growth. In vitro, it modulated the IL-8 response to infection in a vitamin D concentration-dependent manner. Our findings demonstrate that increasing vitamin D levels as pregnancy advances modulate the innate immune system towards a protective response to infection.

Nutritional and Physical Activity Interventions to Improve Immunity

Physical activity and nutrition are important in a healthy lifestyle with potential benefits to immunity often overlooked. Infection of the upper respiratory tract, and the associated symptoms, are the most frequent presentations to general practitioners and may have significant economic and social impact. In this review, we consider the role of physical activity and nutrition in improving immunity. Evidence suggests that regular moderate activity is particularly beneficial for immune enhancement and reducing the risk of infection. We also discuss some nutritional strategies. Unfortunately, the evidence for many is weak. Avoiding nutritional deficiencies seems the most pragmatic recommendation. This can be achieved with a balanced diet. Including a variety of fruits and vegetables may help ensure adequate intake of essential nutrients with little risk of excess intake of any single nutrient. Supplementation with individual nutrients is generally not recommended. Multinutrients may be beneficial for those with a preexisting deficiency but not if normal dietary intake is sufficient. Further benefit may be gained from some supplements including probiotics, bovine colostrum, and some plant-derived products (Echinacea, black elderberry, and some polyphenols) but only in specific situations/contexts. Individuals should consider their personal needs, use caution, and avoid the indiscriminate use of supplements.

Effect of micronutrient supplementation on treatment outcomes in children with intrathoracic tuberculosis: a randomized controlled trial

BACKGROUND

Micronutrients play an important role in immune function. To our knowledge, there have been no comprehensive studies on the role of micronutrient supplementation in children with tuberculosis.

OBJECTIVE

We assessed the effect of micronutrient supplementation in children treated with antituberculosis therapy (ATT).

DESIGN

A randomized, double-blind, placebo-controlled trial that used a 2 × 2 factorial design was undertaken at 2 teaching hospitals in Delhi. Children with newly diagnosed intrathoracic tuberculosis were enrolled, and they received ATT together with daily supplementation for 6 mo with either zinc alone, micronutrients without zinc, micronutrients in combination with zinc, or a placebo. Main outcomes were weight gain and an improvement in a chest X-ray (CXR) lesion assessed at 6 mo of treatment.

RESULTS

A total of 403 children were enrolled and randomly assigned. A microbiological diagnosis of tuberculosis was confirmed in 179 children (44.4%). The median (95% CI) increase in weight-for-age z score at 6 mo was not significantly different between subjects who received micronutrients [0.75 (0.66, 0.84)] and those who did not receive micronutrients [0.76 (0.67, 0.85)] and between subjects who received zinc [0.76 (0.68, 0.85)] and those who did not receive zinc [0.75 (0.66, 0.83)]. An improvement in CXR was observed in 285 children, but there was no difference between those receiving zinc and no zinc or between those receiving micronutrients and no micronutrients after 6 mo of ATT. However, children who received micronutrients had a faster gain in height over 6 mo than did those who did not receive micronutrients (height-for-age z score Δ = 0.08; P = 0.014).

CONCLUSIONS

Micronutrient supplementation did not modify the weight gain or clearance of lesions on CXR in children with intrathoracic tuberculosis. However, micronutrient supplementation during treatment may improve height gain in children with intrathoracic tuberculosis. This trial was registered at clinicaltrials.gov as NCT00801606.

Vitamin D and skeletal muscle function in athletes

PURPOSE OF REVIEW

To highlight recently published data about the vitamin D status of athletes, and effect of vitamin D supplementation on muscle strength and performance in the athletic population.The vitamin D receptor exists in skeletal muscle, and muscle weakness has been reported in individuals who are severely deficient [25(OH)D <25 nmol/l]. Experimental findings reveal the cellular and genomic mechanisms implicating vitamin D in muscle mass, strength and function, and raise questions about the role of vitamin D in the achievement of optimum athletic performance.

RECENT FINDINGS

Athletes appear to have the same risk of vitamin D deficiency and seasonal variance in status as nonathletic members of the same population, with the exception of athletes who train and compete indoors whose risk of deficiency is somewhat greater. Interventions with vitamin D supplements have had mixed results, with a positive effect on muscle function observed only in participants with insufficient status [25(OH)D <50 nmol/l].

SUMMARY

There have been relatively few robust interventions with vitamin D supplementation in athletic populations who are vitamin D deficient, and none which have been able to establish the ideal 25(OH)D concentration for optimum performance.

Effect of high dose vitamin C on Epstein-Barr viral infection

Background Many natural compounds were tested for the ability to suppress viral replication. The present manuscript details an analysis of high dose vitamin C therapy on patients with EBV infection. Material and Methods The data were obtained from the patient history database at the Riordan Clinic. Among people in our database who were treated with intravenous vitamin C (7.5 g to 50 g infusions) between 1997 and 2006, 178 patients showed elevated levels of EBV EA IgG (range 25 to 211 AU) and 40 showed elevated levels of EBV VCA IgM (range 25 to 140 AU). Most of these patients had a diagnosis of chronic fatigue syndrome, with the rest being diagnosed as having mononucleosis, fatigue, or EBV infection. Results Our data provide evidence that high dose intravenous vitamin C therapy has a positive effect on disease duration and reduction of viral antibody levels. Plasma levels of ascorbic acid and vitamin D were correlated with levels of antibodies to EBV. We found an inverse correlation between EBV VCA IgM and vitamin C in plasma in patients with mononucleosis and CFS meaning that patients with high levels of vitamin C tended to have lower levels of antigens in the acute state of disease. In addition, a relation was found between vitamin D levels and EBV EA IgG with lower levels of EBV early antigen IgG for higher levels of vitamin D. Conclusions The clinical study of ascorbic acid and EBV infection showed the reduction in EBV EA IgG and EBV VCA IgM antibody levels over time during IVC therapy that is consistent with observations from the literature that millimolar levels of ascorbate hinder viral infection and replication in vitro.

Link between vitamin D and airway remodeling

In the last decade, many epidemiologic studies have investigated the link between vitamin D deficiency and asthma. Most studies have shown that vitamin D deficiency increases the risk of asthma and allergies. Low levels of vitamin D have been associated with asthma severity and loss of control, together with recurrent exacerbations. Remodeling is an early event in asthma described as a consequence of production of mediators and growth factors by inflammatory and resident bronchial cells. Consequently, lung function is altered, with a decrease in forced expiratory volume in one second and exacerbated airway hyperresponsiveness. Subepithelial fibrosis and airway smooth muscle cell hypertrophy are typical features of structural changes in the airways. In animal models, vitamin D deficiency enhances inflammation and bronchial anomalies. In severe asthma of childhood, major remodeling is observed in patients with low vitamin D levels. Conversely, the antifibrotic and antiproliferative effects of vitamin D in smooth muscle cells have been described in several experiments. In this review, we briefly summarize the current knowledge regarding the relationship between vitamin D and asthma, and focus on its effect on airway remodeling and its potential therapeutic impact for asthma.

Fall in Vitamin D Levels during Hospitalization in Children

Plasma levels of 25-hydroxyvitamin D [25(OH)D] were measured by competitive Electrochemiluminescence Immunoassay (ECLIA) in 92 children (67 boys, 25 girls) aged 3 months to 12 years at admission to hospital (timepoint 1, T1) and at discharge (timepoint 2, T2). There was a significant fall in the mean 25(OH)D from T1 (71.87 ± 27.25 nmol/L) to T2 (49.03 ± 22.25 nmol/L) (mean change = 22.84 nmol/L, P value = 0.0004). Proportion of patients having VDD (levels <50 nmol/L) at admission (25%, 23/92) increased significantly at the time of discharge (51.09%, 47/92) (P = 0.0004). There was a trend towards longer duration of hospital stay, requirement of ventilation and inotropes, development of healthcare-associated infection, and mortality in vitamin D deficient as compared to nondeficient patients though the difference was statistically insignificant. In conclusion, vitamin D levels fall significantly and should be monitored during hospital stay in children. Large clinical studies are needed to prospectively evaluate the effect of vitamin D supplementation in vitamin D deficient hospitalized children on various disease outcome parameters.

The role of the intraplaque vitamin d system in atherogenesis

Vitamin D has been shown to play critical activities in several physiological pathways not involving the calcium/phosphorus homeostasis. The ubiquitous distribution of the vitamin D receptor that is expressed in a variety of human and mouse tissues has strongly supported research on these "nonclassical" activities of vitamin D. On the other hand, the recent discovery of the expression also for vitamin D-related enzymes (such as 25-hydroxyvitamin D-1 α -hydroxylase and the catabolic enzyme 1,25-dihydroxyvitamin D-24-hydroxylase) in several tissues suggested that the vitamin D system is more complex than previously shown and it may act within tissues through autocrine and paracrine pathways. This updated model of vitamin D axis within peripheral tissues has been particularly investigated in atherosclerotic pathophysiology. This review aims at updating the role of the local vitamin D within atherosclerotic plaques, providing an overview of both intracellular mechanisms and cell-to-cell interactions. In addition, clinical findings about the potential causal relationship between vitamin D deficiency and atherogenesis will be analysed and discussed.

Vitamin D: Update 2013: From rickets prophylaxis to general preventive healthcare

Vitamin D has received a lot of attention recently as a result of a meteoric rise in the number of publications showing that vitamin D plays a crucial role in a plethora of physiological functions and associating vitamin D deficiency with many acute and chronic illnesses including disorders of calcium metabolism, autoimmune diseases, some cancers, type 2 diabetes mellitus, infectious diseases and cardiovascular disease. The recent data on vitamin D from experimental, ecological, case-control, retrospective and prospective observational studies, as well as smaller intervention studies, are significant and confirm the sunshine vitamin's essential role in a variety of physiological and preventative functions. The results of these studies justify the recommendation to improve the general vitamin D status in children and adults by means of a healthy approach to sunlight exposure, consumption of foods containing vitamin D and supplementation with vitamin D preparations. In general, closer attention should therefore be paid to vitamin D deficiency in medical and pharmaceutical practice than has been the case hitherto.