Serum level of vitamin D and trace elements in children with recurrent wheezing: a cross-sectional study

Zinc Deficiency and Zinc Supplementation in Allergic Diseases

In recent decades, it has become clear that allergic diseases are on the rise in both Western and developing countries. The exact reason for the increase in prevalence has not been conclusively clarified yet. Multidimensional approaches are suspected in which diet and nutrition seem to play a particularly important role. Allergic diseases are characterized by a hyper-reactive immune system to usually harmless allergens, leading to chronic inflammatory diseases comprising respiratory diseases like asthma and allergic rhinitis (AR), allergic skin diseases like atopic dermatitis (AD), and food allergies. There is evidence that diet can have a positive or negative influence on both the development and severity of allergic diseases. In particular, the intake of the essential trace element zinc plays a very important role in modulating the immune response, which was first demonstrated around 60 years ago. The most prevalent type I allergies are mainly based on altered immunoglobulin (Ig)E and T helper (Th)2 cytokine production, leading to type 2 inflammation. This immune status can also be observed during zinc deficiency and can be positively influenced by zinc supplementation. The underlying immunological mechanisms are very complex and multidimensional. Since zinc supplements vary in dose and bioavailability, and clinical trials often differ in design and structure, different results can be observed. Therefore, different results are not surprising. However, the current literature suggests a link between zinc deficiency and the development of allergies, and shows positive effects of zinc supplementation on modulating the immune system and reducing allergic symptoms, which are discussed in more detail in this review.

Copper homeostasis dysregulation in respiratory diseases: a review of current knowledge

Cu is an essential micronutrient for various physiological processes in almost all human cell types. Given the critical role of Cu in a wide range of cellular processes, the local concentrations of Cu and the cellular distribution of Cu transporter proteins in the lung are essential for maintaining a steady-state internal environment. Dysfunctional Cu metabolism or regulatory pathways can lead to an imbalance in Cu homeostasis in the lungs, affecting both acute and chronic pathological processes. Recent studies have identified a new form of Cu-dependent cell death called cuproptosis, which has generated renewed interest in the role of Cu homeostasis in diseases. Cuproptosis differs from other known cell death pathways. This occurs through the direct binding of Cu ions to lipoylated components of the tricarboxylic acid cycle during mitochondrial respiration, leading to the aggregation of lipoylated proteins and the subsequent downregulation of Fe-S cluster proteins, which causes toxic stress to the proteins and ultimately leads to cell death. Here, we discuss the impact of dysregulated Cu homeostasis on the pathogenesis of various respiratory diseases, including asthma, chronic obstructive pulmonary disease, idiopathic interstitial fibrosis, and lung cancer. We also discuss the therapeutic potential of targeting Cu. This study highlights the intricate interplay between copper, cellular processes, and respiratory health. Copper, while essential, must be carefully regulated to maintain the delicate balance between necessity and toxicity in living organisms. This review highlights the need to further investigate the precise mechanisms of copper interactions with infections and immune inflammation in the context of respiratory diseases and explore the potential of therapeutic strategies for copper, cuproptosis, and other related effects.

Association between dietary zinc intake and asthma in overweight or obese children and adolescents: A cross-sectional analysis of NHANES

Background

Asthma, characterized by recurrent wheezing, breathlessness, chest tightness, and coughing, is a major health concern among children and adolescents worldwide, currently affecting more than 5 million children. The increasing prevalence of obesity and overweight among the pediatric population has made the issue of childhood respiratory health more complex. Compared with children of healthy weight, the risk of asthma is higher in overweight and obese children. Zinc, a nutrient that regulates the oxidant-antioxidant balance, has been studied for its potential protective effects against asthma in adults and children. However, the results are controversial, with some studies reporting a beneficial effect and others showing no effect. Therefore, our objective was to assess the correlation between zinc intake from diet and asthma occurrence among children and adolescents who are overweight or obese.

Methods

The National Health and Nutrition Examination Survey (NHANES) (2011-2020) provided data on individuals aged ≤20 who were overweight or obese, had asthma, and consumed zinc in their diet. The association between dietary zinc and asthma was evaluated using a variety of statistical methods, including multivariate logistic regression, restricted cubic spline analysis, and subgroup analysis.

Results

A total of 4597 pediatrics and adolescents were enrolled, with 20.9% (963/4597) suffering from asthma. After adjusting for all covariates in the multivariate logistic regression, compared with the lowest zinc intake group Q1(≤5.68 mg/day), the adjusted OR values for zinc intake and asthma in Q2 (5.69-8.36 mg/day), Q3 (8.37-11.95 mg/day), and Q4 (≥11.96 mg/day) were 0.78 (95% CI: 0.62-0.98, p = 0.03), 0.76 (95% CI: 0.6∼0.98, p = 0.032), 0.71 (95% CI: 0.53∼0.95, p = 0.022), respectively. Stratified analysis showed no interactive role for dietary zinc intake and asthma in overweight or obese children and adolescents.

Conclusions

Dietary zinc intake is inversely associated with asthma in overweight or obese children and adolescents.

A case-control study on asthma and obese patients: Influence of lifestyle patterns, serum trace elements, heavy metals, and total antioxidants

Background and aim

Asthma is a chronic airway hyperresponsiveness disorder and Obese people have greater rates of asthma incidence and prevalence. Obesity, a complex condition, can cause nutritional metabolic problems that change trace elements and minerals. Trace element and antioxidant levels affect asthma aetiology. In this study, we aim to determine the serum levels of trace elements Zn, Fe, Cu, Mg, Co, Ni, Pb, Cd, and Cr, total antioxidants (TAS), and lifestyle that determine specific clinical conditions in asthma and obesity patients from Vellore City (Tamil Nadu, India).

Methods

A case-control study to determine the level of the serum trace elements with 838 subjects (n = 242 asthma patients, n = 140 asthmatic obese, n = 185 obese patients, and n = 271 controls) between the ages of 20 and 60 years was carried out. Asthma was diagnosed based on the clinical examination and pulmonary function tests. Trace element levels were determined by atomic absorption spectrophotometry (AAS) in serum, and a DPPH-free radical scavenging assay was used to determine the total antioxidant capacity level in serum.

Result

In asthma male patients, serum levels of Zn, Fe, Cu, Mg, and TAS were significantly lower and Pb, Cd, and Cr significantly higher, whereas in female asthma patients, serum levels of Zn, Fe, Mg, and TAS were significantly lower and Pb significantly higher. In asthmatic obese male patients, Fe, Cu, and TAS were significantly lower, and Pb, Cd, and Co were significantly higher; in asthmatic obese female patients, Zn, Fe, Cu, Mg, and TAS were significantly lower, and Ni was significantly higher. In obese male patients, Zn, Fe, Cu, and TAS were significantly lower and Cd was significantly higher, and in obese female patients, Zn, Fe, Cu, Mg, and TAS were significantly lower.

Conclusion

The influence of the level of trace elements, heavy metal, total antioxidant, and the lifestyle patterns, may increase the risk of asthma and obesity.

Association Between Circulating Zinc and Risk for Childhood Asthma and Wheezing: A Meta-analysis on 21 Articles and 2205 Children

Asthma is one of the most frequent chronic diseases in children, and growing focus is placed on the exploration of attributable risk factors. Currently, no consensus has been reached on the implication of circulating zinc in the development of asthma. We aimed to conduct a meta-analysis to examine the association between circulating zinc and risk for childhood asthma and wheezing. We searched PubMed, Web of Science, EMBASE, and Google Scholar from inception until December 1, 2022. All procedures were performed independently and in duplicate. Random-effects model was adopted to derive standardized mean difference (SMD) and 95% confidence interval (95% CI). Statistical analyses were completed using the STATA software. Twenty-one articles and 2205 children were meta-analyzed. Overall, there was a statistically significant association between circulating zinc and risk for childhood asthma and wheezing (SMD: -0.38; 95% CI: -0.60 to -0.17; I2=82.6%, p<0.001), without evidence of publication bias as revealed by Begg's (p=0.608) and Egger (p=0.408) tests. Subgroup analyses showed that children with asthma or wheezing in Middle Eastern countries had significantly lower circulating zinc levels than controls (SMD: -0.42; 95% CI: -0.69 to -0.14; p<0.001; I2=87.1%). Additionally, average circulating zinc levels in asthma children were 0.41 μg/dl lower than that in controls, and the difference was statistically significant (SMD: -0.41; 95% CI: -0.65 to -0.16; p<0.001; I2=83.7%). By contrast, children with wheezing were 0.20 μg/dl lower than that in controls, and no between-group difference was noted (SMD=-0.20; 95% CI: -0.58 to 0.17; p=0.072; I2=69.1%). Our findings indicated that circulating zinc was associated with a significant risk for childhood asthma and its related symptom wheezing.

Association of serum zinc levels and symptom control of asthma in children and adolescents- a prospective observational study

Dysregulation of zinc (Zn) homeostasis causes a shift in the Th1/Th2 balance towards a Th2 response, which may lead to a heightened inflammatory response. Asthma is associated with an exaggerated Th2 response to antigens. This study attempts to find the association of serum Zn with the status of symptom control of asthma in children and adolescents with bronchial asthma. A total of 67 asthmatic children, diagnosed as per Global Initiative for Asthma (GINA) 2019 guidelines, were included in the study. Symptom control of asthma was assessed by Asthma Control Test (ACT) and Childhood Asthma Control Test (C-ACT) scores. Spirometry was performed on those participants who were able to perform satisfactorily. Serum Zn was analyzed using the photometric method. Participants were divided into two groups: controlled and uncontrolled groups according to ACT/C-ACT score. Mean age of the participants was 10.78 ± 3.67 years. The mean S. Zn (µg/dL) was 136.97 ± 48.37. This study found a higher mean S. Zn value in the controlled asthma group as compared to the uncontrolled group (158.06 vs 129.23, p = 0.006). At a cutoff of S. Zn (µg/dL) ≥ 126.84, it predicted controlled asthma with a sensitivity of 89% and a specificity of 55%. No significant difference was found between the mean serum Zn levels in terms of age, sex, severity, and CRP levels.

CONCLUSION

A significant difference was observed between the mean value of Zn and symptom control of asthma (p = 0.006) with a weak positive correlation between the two which was statistically significant (rho = 0.26, p = 0.031). However, low levels of zinc were not significantly associated with symptom control of asthma. Thus, we conclude that maintaining an adequate zinc level could help in achieving better control of asthma in pediatric populations.

WHAT IS KNOWN

• Zinc has a role in immunological response in the pathophysiology of immunological disorders such as bronchial asthma.

WHAT IS NEW

• This study adds a significant association of serum zinc levels with symptom control of asthma in pediatric populations. • This study also gives a cut-off value of serum zinc level which predicts adequate symptom control of asthma.

Exposure to Heavy Metals and Allergic Outcomes in Children: a Systematic Review and Meta-analysis

It has been reported that heavy metals have adverse effects on the immune system. However, the relationship between heavy metal exposure and allergic outcomes remains unclear. This systematic review was conducted to examine whether heavy metal exposure is associated with allergic outcomes during childhood. We performed a systematic search of all relevant articles in Web of Science, EMBASE, and PubMed, from inception through to November 2020. We used odds ratio (OR) and the standard mean differences (SMDs) with 95% confidence intervals (CIs) to present estimates from individual studies. In addition, random-effects meta-analysis was used to pool the data. We also conducted the meta-regression and subgroup analysis to explore potential sources of heterogeneity. After duplicate removal, we finally included 35 articles in the systematic review and meta-analysis from an initial 11,181 articles. The overall results showed that copper (Cu) was associated with asthma (pooled SMD = 1.50, 95% CI = 0.13-2.86); in the subgroup analysis, the results indicated that lead (Pb) was associated with asthma (pooled OR = 6.27, 95% CI = 2.24-17.56), and Cu and Pb were connected with atopic dermatitis (SMD =  - 1.05, 95% CI =  - 1.45 to - 0.65; SMD = 5.68, 95% CI = 5.05-6.32), respectively. Mercury (Hg) was associated with atopic dermatitis (pooled OR = 1.13, 95% CI = 1.04-1.22) and wheeze (OR = 1.20, 95% CI = 1.05-1.37). The meta-analysis results indicate that Cu might be connected with childhood asthma, but not with other allergic diseases; Hg and Pb may have no association with allergic diseases during childhood. Given some limits observed in the current studies, more prospective cohort studies are still needed to verify our findings. Review registration: PROSPERO CRD42020222167.

A cross-sectional study on the effect of dietary zinc intake on the relationship between serum vitamin D3 and HOMA-IR

Introduction

Serum vitamin D₃ concentration is associated with the risk of insulin resistance. Zinc has also been reported to be associated with a lower risk of insulin resistance. In addition, zinc is an essential cofactor in the activation of vitamin D₃. However, the effect of dietary zinc intake on the relationship between vitamin D₃ and insulin resistance risk has not been fully studied. Therefore, we designed this cross-sectional study to assess the impact of changes in zinc intake on the relationship between vitamin D₃ and insulin resistance risk.

Study design and methods

This study analyzed data from the national Health and Nutrition Examination Survey (NHANES) from 2005 to 2018, involving 9,545 participants. Participants were stratified by zinc intake category (low zinc intake <9.58 mg/ day; High zinc intake: ≥9.58 mg/ day).

Results

In this cross-sectional study, serum vitamin D₃ levels were independently associated with the risk of insulin resistance in both the low and high Zinc intakes (β: −0.26, 95%Cl: −0.56~0.04 vs. β: −0.56, 95%Cl: −1.01~-0.11). In addition, this association was influenced by different dietary zinc intakes (interaction P < 0.05).

Conclusions

Our results suggest that zinc intake may influence the association between serum vitamin D₃ and the risk of insulin resistance. Further randomized controlled trials are needed to provide more evidence of this finding.

Micronutrients and the Risk of Allergic Diseases in School Children

Microelements and vitamins are believed to have immunomodulatory effects. The aim of the study was to establish the role of antioxidants (vitamins A, E, D) and microelements such as copper (Cu), selenium (Se), and zinc (Zn) levels in allergic diseases in schoolchildren. The study uses a cohort of 80 children (40 with and 40 without allergy/asthma diagnosis) aged 9 to 12 years recruited for the Polish Mother and Child Cohort Study. At nine to twelve years old, the children were tested for microelement and vitamin content and health status (including skin-prick test and spirometry, urine cotinine level). Demographic data were collected from mothers by an allergist. The risk of asthma occurrence was found to be significantly related to the levels of Cu and Zn. The level of Cu was also particularly closely associated with allergic rhinitis and was indicated as a significant predictor of food allergy. The levels of Cu and Zn, and poor nutritional status in general, can influence the immune system and may be considered risk factors for developing asthma, allergic rhinitis and food allergy.

The Role of Zinc in the Pathogenesis of Lung Disease

Lung diseases, such as asthma, chronic obstructive pulmonary diseases (COPD), and cystic fibrosis (CF), are among the leading causes of mortality and morbidity globally. They contribute to substantial economic burdens on society and individuals. Currently, only a few treatments are available to slow the development and progression of these diseases. Thus, there is an urgent unmet need to develop effective therapies to improve quality of life and limit healthcare costs. An increasing body of clinical and experimental evidence suggests that altered zinc and its regulatory protein levels in the systemic circulation and in the lungs are associated with these disease’s development and progression. Zinc plays a crucial role in human enzyme activity, making it an essential trace element. As a cofactor in metalloenzymes and metalloproteins, zinc involves a wide range of biological processes, such as gene transcription, translation, phagocytosis, and immunoglobulin and cytokine production in both health and disease. Zinc has gained considerable interest in these lung diseases because of its anti-inflammatory, antioxidant, immune, and metabolic modulatory properties. Here we highlight the role and mechanisms of zinc in the pathogenesis of asthma, COPD, CF, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, and pulmonary hypertension.

Mineral Micronutrients in Asthma

Asthma represents one of the most common medical issues in the modern world. It is a chronic inflammatory disease characterized by persistent inflammation of the airways and disturbances in redox status, leading to hyperresponsiveness of bronchi and airway obstruction. Apart from classical risk factors such as air pollution, family history, allergies, or obesity, disturbances of the levels of micronutrients lead to impairments in the defense mechanisms of the affected organism against oxidative stress and proinflammatory stimuli. In the present review, the impact of micronutrients on the prevalence, severity, and possible risk factors of asthma is discussed. Although the influence of classical micronutrients such as selenium, copper, or zinc are well known, the effects of those such as iodine or manganese are only rarely mentioned. As a consequence, the aim of this paper is to demonstrate how disturbances in the levels of micronutrients and their supplementation might affect the course of asthma.

Role of intracellular zinc in molecular and cellular function in allergic inflammatory diseases

Zinc is an essential micronutrient in human body and a vital cofactor for the function of numerous proteins encoded by the human genome. Zinc has a critical role in maintaining many biochemical and physiological processes at the molecular, cellular, and multiple organ and systemic levels. The alteration of zinc homeostasis causes dysfunction of many organs and systems. In the immune system, zinc regulates the differentiation, proliferation and function of inflammatory cells, including T cells, eosinophils, and B cells, by modifying several signaling pathways such as NFκB signaling pathways and TCR signals. An adequate zinc level is essential for proper immune responses and decreased zinc levels were reported in many allergic inflammatory diseases, including atopic dermatitis, bronchial asthma, and chronic rhinosinusitis. Decreased zinc levels often enhance inflammatory activation. On the other hand, the inflammatory conditions alter the intracellular homeostasis of zinc, often decreasing zinc levels. These findings implied that there could be a vicious cycle between zinc deficiency and inflammatory conditions. In this review, we present recent evidence on the involvement of zinc in atopic dermatitis, bronchial asthma, and chronic rhinosinusitis, with insights into the involvement of zinc in the underlying molecular and cellular mechanisms related to these allergic inflammatory diseases.

Serum zinc level and children`s asthma: A systematic and meta-analysis review article

BACKGROUND

Asthma is a chronic inflammatory respiratory disorder. Nutritional conditions affect allergic diseases such as asthma. The aim of this study was to review the serum zinc level in children with asthma.

METHODS

This is a review article found in databases such as Google, PubMed, SID, Irandoc, Scopus and up-to-date. Key words for search included zinc, asthma, children and pediatric. There was no time limitation for the search. These articles on zinc levels in asthmatic children were meta-analyzed.

RESULTS

Out of the 40 articles, 19 articles were excluded and 21 articles were included in this analysis. 15 articles evaluated serum zinc levels, 4 articles on hair zinc levels, one article evaluated nail zinc levels and another on zinc level in erythrocyte cells in children with asthma. Only 3 articles evaluated effects of zinc supplement treatment in children with asthma. Meta-analysis of studies showed that there was no significant difference between the standard mean differences of zinc level in asthmatic patients compared to the control group. We cannot analyze the association between zinc levels in hair and nail in children with asthma. All clinical trial studies show that zinc supplement improves clinical manifestations of asthma and patient's pulmonary function test.

CONCLUSION

We found that the mean serum zinc level difference is not significant in children with asthma than healthy control group and it seems that there is no relation between mean serum zinc level and severity of asthma in children.

Association between toenail zinc concentrations and incidence of asthma among American young adults: The CARDIA study

BACKGROUND

As an essential micronutrient, zinc plays an important role in modulating the immune system. However, data on the association between zinc concentrations and asthma incidence are sparse, especially in adults.

METHODS

We prospectively followed up 3682 individuals aged 20-32 years without history of asthma or current asthma at baseline from 1987-1988 to 2015-2016. Zinc concentrations were measured in toenail clippings collected at Exam Year 2 using inductively-coupled-plasma mass spectroscopy. Asthma was diagnosed by a physician and/or reported medication use for asthma control with verification. Cox regression was used to model the association between toenail zinc concentrations and asthma incidence.

RESULTS

Over an average of 22.5 years of follow-up, 508 incident cases of asthma were identified. After adjustment for potential confounders, no statistically significant association was found between zinc concentration and asthma incidence (HR = 0.81; 95% CI: 0.62, 1.07; Plinear trend = 0.26). The observed association was not materially modified by sex, body mass index, smoking or atopic status. When stratifying data by race, a significant inverse linear association was found among African Americans (per 1 standard deviation increment in toenail zinc concentrations: HR = 0.86; 95% CI: 0.75, 0.99; Plinear trend = 0.03), but not in Caucasians (HR = 1.07; 95% CI: 0.91, 1.25; Plinear trend = 0.42), though the test for interaction was not statistically significant (Pinteraction = 0.099).

CONCLUSIONS

Findings from this prospective cohort study do not support a significant longitudinal association between toenail zinc concentrations and incidence of asthma among American young adults. Future studies are needed to confirm our findings.

Vitamin D Supplementation As a Potential therapeutic Mediator in Asthma: Does Dose Really Matter? a Critical Review of the Literature

Around 400 million people across the globe will suffer from asthma in the next 10 years. Although most asthmatics use asthma medications regularly, they occasionally visit the emergency department for aggressive treatment amidst family anxiousness. Vitamin D (VD) not only regulates the expression of genes associated with calcium homeostasis, but also the genes associated with cancers, autoimmune diseases, and infection. VD has also non-genomic activities e.g. it is a potentially safe and effective novel strategy for decreasing the asthma episodes and controlling exacerbations. Our review assessed the dose, serum level, duration of administration and outcomes of VD in cases of asthmas. Although a body of research evidences the effectiveness of VD supplementation in asthma, other studies showed the insignificant response of VD to asthma either with low dose or low achieved serum VD levels. Nevertheless, recent reviews suggest that manipulating VD status holds promise for primary prevention and treatment of asthma. Future research on the relationship between VD and asthma should consider utilizing adequate doses of VD preparations for sufficient duration (likely to be >12 months) aiming to achieve appropriate level of serum VD (25-hydroxyvitamin D) concentration (likely to be at least >40 ng/mL).

Vitamin D and Immunity in Infants and Children

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

The Role of Vitamin D Deficiency in Children With Recurrent Wheezing-Clinical Significance

Recurrent wheezing (RW) in infancy is one of the most frequent reasons for parents to consult health care providers and creates a significant global burden. Clinical course of RW is difficult to predict, also which infants will progress to asthma, since no valid biomarkers have been established. Identification of those infants with RW who are at risk of further recurrences and/or severe acute respiratory tract infection (ARTI) could help pediatricians to improve their therapeutic decisions. Increasing research interest is focused on the extra-skeletal actions of vitamin D (VD) and the clinical impact of VD insufficiency/deficiency. As VD deficiency could be a risk factor for causing RW in children, measurement of their serum level of 25-hydroxycholecalciferol [25(OH)D] is recommended. In the case of deficiency, VD administration is recommended in age-appropriate doses for at least 6 weeks, until achievement of normal blood 25(OH)D level, followed by supplementation as long as exposure to sun is inadequate. Higher doses of VD given in an attempt to prevent asthma development appear to be of no additional benefit. In children with severe ARTI, VD level is recommended to be assess.

Lower circulating zinc and selenium levels are associated with an increased risk of asthma: evidence from a meta-analysis

OBJECTIVE

Previous studies evaluating the associations of circulating Zn and Se levels with asthma have produced inconsistent results. Therefore, we conducted a meta-analysis to summarize and quantitatively synthesize the evidence from observational research.

DESIGN

Meta-analysis.

SETTING

We searched PubMed, Web of Science and Scopus databases up to May 2019 for relevant available articles. Random-effects model was adopted to estimate the pooled standardized mean difference (SMD) with 95 % CI. Meta-regression analysis and 'leave-one-out' sensitivity analysis were used to assess heterogeneity.

PARTICIPANTS

The meta-analysis focused on general populations.

RESULTS

A total of twenty-six studies for Zn and forty studies for Se were included in the meta-analysis. The overall analyses identified that asthma patients had lower Zn (SMD = -0·40; 95 % CI -0·77, -0·03; I2 = 94·1 %) and Se (SMD = -0·32; 95 % CI -0·48, -0·17; I2 = 90·9 %) levels in serum or plasma compared with healthy controls. After removing the studies that contributed to the heterogeneity, the pooled SMD were -0·26 (95 % CI -0·40, -0·13; I2 = 37·42 %) for Zn and -0·06 (95 % CI -0·13, 0·02; I2 = 43·54 %) for Se.

CONCLUSIONS

Lower circulating Zn and Se levels might be associated with an increased risk of asthma.

The relation between serum vitamin D levels, viral infections and severity of attacks in children with recurrent wheezing

INTRODUCTION AND OBJECTIVES

Vitamin D deficiency is associated with increased susceptibility to infections and wheezing. We aimed to evaluate the relation between vitamin D levels, viral infections and severity of attacks in children with recurrent wheezing.

MATERIALS AND METHODS

A total of 52 patients who applied with wheezing, at the ages of 12-60 months with a history of three or more wheezing attacks in the last year and 54 healthy children were included. Sociodemographic data, risk factors for recurrent wheezing, and the severity of the wheezing attacks were recorded. 25(OH)D3, calcium, phosphor, alkaline phosphatase and parathormone levels of all children were measured. Nasopharyngeal samples of the patients for viruses were studied by multiplex polymerase chain reaction.

RESULTS

For the patient group, being breastfed for six months or less, history of cesarean section, cigarette exposure, humid home environment, and family history of allergic disease were significantly higher compared with the control group. Serum vitamin D levels in the patient group were significantly lower compared to the control group. There was no significant relationship between vitamin D levels and hospitalization, oxygen or steroid therapy. Virus was detected in 38 patients (73%). Rhinovirus (63.2%) was the most frequently detected virus. Coinfection was found in 14 (36.8%) patients. There was no statistically significant difference between detection of virus and vitamin D levels.

CONCLUSIONS

Cigarette exposure, being breastfed six months or less, humid home environment, history of cesarean section, family history of allergic disease and vitamin D deficiency might be risk factors for recurrent wheezing.

Vitamin D for secondary prevention of acute wheeze attacks in preschool and school-age children

INTRODUCTION

Vitamin D is best known for its role in bone health; however, the discovery of the vitamin D receptor and the expression of the gene encoding the vitamin D 1α-hydroxylase (CYP27B1) enzyme in a wide variety of tissues including immune cells and respiratory epithelium has led to the discovery of potential roles for vitamin D in the prevention of acute wheeze.

METHODS

We review here the literature concerning the relationships between circulating 25-hydroxyvitamin D (25(OH)D) concentration and secondary prevention of acute wheeze attacks in preschool and school-age children.

RESULTS

Epidemiological data suggest that vitamin D insufficiency (25(OH)D <75 nmol/L) is highly prevalent in preschool and school-age children with wheeze. Preschool age children with a history of wheeze attacks and circulating 25(OH)D <75 nmol/L are at increased risk and frequency of future acute wheeze. However, no consistent association between low vitamin D status and risk of acute wheeze is reported in school-age children. Seven randomised controlled trials (RCTs) with relatively small sample sizes (30-430) and variable quality showed inconsistent results regarding the effect of oral vitamin D supplementation during childhood on the risk of asthma attacks, asthma symptom control, inhaled corticosteroid requirements, spirometry and unscheduled healthcare attendances for wheeze. A RCT showed that vitamin D supplementation had no effect on the frequency of unplanned healthcare attendances due to acute wheeze in 22 preschool children.

DISCUSSION

An evidence-based recommendation for the use of vitamin D as a preventive therapy for wheeze attacks cannot be made until results of further trials are available. The assessment of circulating 25(OH)D concentration and the optimisation of vitamin D status to prevent acute respiratory tract infections, and to maintain skeletal and general health in preschool and school-age children with acute wheeze is worthwhile in its own right, but whether this will reduce the risk of acute wheeze attacks is unclear.

Predicting Asthma Using Clinical Indexes

Asthma is no longer considered a single disease, but a common label for a set of heterogeneous conditions with shared clinical symptoms but associated with different cellular and molecular mechanisms. Several wheezing phenotypes coexist at preschool age but not all preschoolers with recurrent wheezing develop asthma at school-age; and since at the present no accurate single screening test using genetic or biochemical markers has been developed to determine which preschooler with recurrent wheezing will have asthma at school age, the asthma diagnosis still needs to be based on clinical predicted models or scores. The purpose of this review is to summarize the existing and most frequently used asthma predicting models, to discuss their advantages/disadvantages, and their accomplishment on all the necessary consecutive steps for any predictive model. Seven most popular asthma predictive models were reviewed (original API, Isle of Wight, PIAMA, modified API, ucAPI, APT Leicestersher, and ademAPI). Among these, the original API has a good positive LR~7.4 (increases the probability of a prediction of asthma by 2-7 times), and it is also simple: it only requires four clinical parameters and a peripheral blood sample for eosinophil count. It is thus an easy model to use in any rural or urban health care system. However, because its negative LR is not good, it cannot be used to rule out the development of asthma.

The immunomodulatory role of zinc in asthmatic patients

BACKGROUND

Zinc deficiency may play an important role in the development of atopic asthma.

THE AIM OF THE WORK

To assess serum zinc levels in adult atopic, non-atopic asthmatic patients, and in healthy controls and to investigate its modulatory effect on production of interferon gamma (IFN-γ) and interleukin-10 (IL-10) by peripheral blood mononuclear cells (PBMCs) in vitro.

METHODS

Sixty asthmatics and 30 apparently healthy volunteers were included in this study. All patients were subjected to history taking, clinical examination, pulmonary function tests, skin prick test (SPT), serum zinc assessment by a colorimetric method as well as serum total IgE measurement by Enzyme-linked immunosorbent assay (ELISA). PBMCs were activated in vitro in the presence and absence of zinc, and then cell culture supernatants were analyzed for IFN-γ and IL-10 by ELISA.

RESULTS

Serum zinc levels were significantly lower in atopic asthmatics than non-atopic asthmatics and healthy controls. In atopic asthmatics, highly significant correlations were found between zinc levels and total Ig E levels as well as FEV1. In culture, zinc triggers IFN-γ and inhibits IL-10 production by PBMCs, in atopic asthmatics. In non atopic asthmatics and healthy controls, IFN-γ and IL-10 were slightly affected by zinc supplementation in culture.

CONCLUSION

Serum zinc levels affect asthma phenotypes. Atopic asthmatics might benefit from zinc supplements.

Vitamin D Status in Infants with Two Different Wheezing Phenotypes

OBJECTIVE

To investigate vitamin D levels in patients with recurrent wheeze at early ages of childhood.

METHODS

In the present cross-sectional study, serum 25-hydroxy vitamin D [25 (OH)D], levels which is known as an indicator of vitamin D adequacy, was examined in infants with three or more wheezing attacks.

RESULTS

A total of 186 infants with recurrent wheezing were included in the study along with 118 healthy control peers. The recurrent wheezing study participants were classified into two groups according to Asthma Predictive Index (API) positivity and compared to control subjects regarding their serum vitamin D status. The API negative group had the lowest mean serum 25 (OH)D level (n = 121; 22.71 ± 10.76 ng/ml) followed by API positive group (n = 65; 24.08 ± 9.02 ng/ml) compared to healthy group (26.24 ± 11.88 ng/ml) (p < 0.05). In addition, higher vitamin D deficiency was observed in infants in API negative group (52.1 %; p < 0.01) and API positive group (38.5 %; p < 0.05) than control group (31.4 %).

CONCLUSIONS

Low levels of 25 (OH)D were detected in infants with two different phenotypes of recurrent wheeze. Vitamin D deficiency may play a role in the pathogenesis of infants with recurrent wheezing.

Vitamin D3 transactivates the zinc and manganese transporter SLC30A10 via the Vitamin D receptor

Vitamin D3 regulates genes critical for human health and its deficiency is associated with an increased risk for osteoporosis, cancer, diabetes, multiple sclerosis, hypertension, inflammatory and immunological diseases. To study the impact of vitamin D3 on genes relevant for the transport and metabolism of nutrients and drugs, we employed next-generation sequencing (NGS) and analyzed global gene expression of the human-derived Caco-2 cell line treated with 500nM vitamin D3. Genes involved in neuropeptide signaling, inflammation, cell adhesion and morphogenesis were differentially expressed. Notably, genes implicated in zinc, manganese and iron homeostasis were largely increased by vitamin D3 treatment. An ∼10-fold increase in ceruloplasmin and ∼4-fold increase in haptoglobin gene expression suggested a possible association between vitamin D and iron homeostasis. SLC30A10, the gene encoding the zinc and manganese transporter ZnT10, was the chiefly affected transporter, with ∼15-fold increase in expression. SLC30A10 is critical for zinc and manganese homeostasis and mutations in this gene, resulting in impaired ZnT10 function or expression, cause manganese intoxication, with Parkinson-like symptoms. Our NGS results were validated by real-time PCR in Caco-2 cells, as well as in duodenal biopsies taken from healthy human subjects treated with 0.5μg vitamin D3 daily for 10 days. In addition to increasing gene expression of SLC30A10 and the positive control TRPV6, vitamin D3 also increased ZnT10 protein expression, as indicated by Western blot and cytofluorescence. In silico identification of potential vitamin D responsive elements (VDREs) in the 5'-flanking region of the SLC30A10 promoter and dual-luciferase reporter assay showed enhanced promoter activity in the presence of vitamin D receptor (VDR) and retinoid X receptor (RXR) constructs, as well as vitamin D3, but not when one of these factors was absent. Electrophoretic mobility shift assay (EMSA) and competition EMSA revealed binding of select sequences, namely, nt -1623/-1588 and nt -1758/-1723 relative to the transcription start site, to VDR-containing nuclear extracts. In conclusion, we have shown that vitamin D3 transactivates the SLC30A10 gene in a VDR-dependent manner, resulting in increased ZnT10 protein expression. Because SLC30A10 is highly expressed in the small intestine, it is possible that the control of zinc and manganese systemic levels is regulated by vitamin D3 in the intestine. Zinc, manganese and vitamin D are important for bone metabolism and brain health. Future examination of a possible role for supplementation or chelation of zinc and manganese, alongside vitamin D3 administration, will further our understanding of its potential benefit in the treatment of specific illnesses, such as osteoporosis and Parkinson's disease.

Association between Concentrations of Metals in Urine and Adult Asthma: A Case-Control Study in Wuhan, China

BACKGROUND

Several metals have been reported to be associated with childhood asthma. However, the results on relationships between metals and risk of childhood asthma are inconclusive, and the research on adult asthma in the Chinese general population is rare.

OBJECTIVES

To investigate potential associations between levels of urinary metals and adult asthma.

METHODS

A case-control study of 551 adult asthma cases and 551 gender- and age-matched controls was conducted in Wuhan, China. Demographic information was obtained, and lung function was assessed. The urinary concentrations of 22 metals were measured by inductively coupled plasma mass spectrometry.

RESULTS

After adjusting for other metalsand other covariates, urinary cadmium, molybdenum, chromium, copper, uranium and selenium were positively associated with asthma, with odds ratios (95% CI) of 1.69 (1.00, 2.85), 3.76 (2.30, 6.16), 4.89 (3.04, 7.89), 6.06 (3.27, 11.21), 6.99 (4.37, 11.19) and 9.17 (4.16, 20.21), respectively. By contrast, urinary lead, barium, iron, zinc, nickel, manganese and rubidium were negatively associated with asthma, with odds ratios (95% CI) of 0.48 (0.29, 0.80), 0.44 (0.27, 0.71), 0.41 (0.26, 0.64), 0.40 (0.24, 0.66), 0.30 (0.22, 0.41), 0.23 (0.14, 0.39) and 0.07 (0.03, 0.15), respectively. When comparing urinary metals in different subgroups of cases with those in matched controls, the associations of above 13 metals with asthma prevalence were nearly the same.

CONCLUSIONS

Our results suggested that asthma prevalence in the Chinese adults was positively associated with urinary chromium, chromium, selenium, molybdenum, cadmium, and uranium, and negatively associated with urinary manganese, iron, nickel, zinc, rubidium, barium and lead. Additional research with larger populations in different regions is required to support our findings.

Zinc enhances the number of regulatory T cells in allergen-stimulated cells from atopic subjects

PURPOSE

The trace element zinc is essential for immune function and its regulation. Since zinc deficiency and allergic hyperresponsive reactions are often accompanied, the influence of zinc on allergen-induced cell growth, CD4+ regulatory T (Treg) cell numbers and cytokine expression during allergic immune reactions was investigated.

METHODS

Peripheral blood mononuclear cells (PBMCs) from non-atopic and atopic subjects were treated with timothy grass allergen pre-incubated with or without zinc. Proliferation was determined by analyzing the incorporation of ³H-thymidine. Intracellular zinc and Foxp3 levels and cell surface antigens were measured by FACS, cytokine expression by ELISA and real-time PCR.

RESULTS

Incubation with 50 μM zinc sulfate (Zn50) enhances cytosolic zinc concentrations in CD3+ T cells. The data also reveal that the combination of Zn50 plus allergen significantly reduces PBMC proliferation of atopic subjects. Additionally, Zn50 plus allergen enhances Th1 cytokine responses shown by increased interferon (IFN)-γ/interleukin (IL)-10 ratios as well as enhanced tumor necrosis factor-α release. In response to allergen, zinc increases Treg cells and upregulates the mRNA expression of cytotoxic T-lymphocyte antigen-4 in atopic subjects. Interestingly, Zn50 alone leads to an increase of CD4+CD25high(hi)+ cells in atopic and non-atopic subjects.

CONCLUSIONS

Zinc may regulate unwanted hyperresponsive immune reactions by suppressing proliferation through a significant shift from IL-10 to the Th1 cytokine IFN-γ, and enhanced regulatory T cell numbers. Therefore, zinc supplementation may be a promising tool for the therapy of allergies, without negatively affecting the immune system.

Vitamin D exposure during pregnancy, but not early childhood, is associated with risk of childhood wheezing

The association between vitamin D and wheezing in early childhood is unclear. The primary objective of this study was to evaluate the association between vitamin D exposure, during both pregnancy and childhood, and early childhood wheezing. Secondary objectives were to evaluate the associations between vitamin D exposures and asthma and wheezing severity. We conducted a cohort study of children (0-5 years) recruited from 2008 to 2013 through the TARGet Kids! primary-care research network. Vitamin D exposures included maternal vitamin D supplement use during pregnancy, child vitamin D supplementation and children's 25-hydroxyvitamin D (25(OH)D) concentrations. The outcomes measured were parent-reported childhood wheezing, diagnosed asthma and wheezing severity. Vitamin D supplement and wheezing data were available for 2478 children, and blood samples were available for 1275 children. Adjusted odds ratios (aOR) were estimated using logistic regression adjusted for age, sex, ethnicity, body mass index, birth weight, outdoor play, breastfeeding duration, daycare status, parental smoking and family history of asthma. Vitamin D supplementation during pregnancy was associated with lower odds of childhood wheezing (aOR=0.65; 95% CI: 0.46-0.93). In early childhood, neither 25(OH)D (aOR per 10 nmol/l=1.01; 95% CI: 0.96-1.06) nor vitamin D supplementation (aOR=1.00; 95% CI: 0.81-1.23) was associated with wheezing. No significant associations were observed with diagnosed asthma or wheezing severity. Vitamin D supplementation during pregnancy was associated with reduced odds of wheezing, but child vitamin D supplementation and childhood 25(OH)D were not associated with reduced wheezing. The timing of exposure may be important in understanding the association between vitamin D and childhood wheezing.

Vitamin D as an adjunctive therapy in asthma. Part 2: A review of human studies

Vitamin D deficiency (VDD) is highly prevalent worldwide, with adverse effects on bone health but also potentially other unfavorable consequences. VDD and asthma-incidence/severity share many common risk factors, including winter season, industrialization, poor diet, obesity, dark skin pigmentation, and high latitude. Multiple anatomical areas relevant to asthma contain both the enzyme responsible for producing activated vitamin D and the vitamin D receptor suggesting that activated vitamin D (1,25-dihydroxyvitamin D) may have important local effects at these sites. Emerging evidence suggests that VDD is associated with increased airway hyperresponsiveness, decreased pulmonary function, worse asthma control, and possibly decreased response to standard anti-asthma therapy. However the effect is inconsistent with preliminary evidence from different studies suggesting vitamin D is both beneficial and detrimental to asthma genesis and severity. Current evidence suggests that supplementation with moderate doses of vitamin D may be appropriate for maintenance of bone health in asthmatics, particularly steroid users. However emerging data from an increasing number of randomized, controlled, intervention studies of vitamin D supplementation in pediatric and adult asthma are becoming available and should help determine the importance, if any of vitamin D for asthma pathogenesis. The purpose of this second of a two-part review is to review the current human literature on vitamin D and asthma, discussing the possible consequences of VDD for asthma and the potential for vitamin D repletion as adjunct therapy.

The Role of Vitamin D in Pediatric Asthma

The detrimental effects of vitamin D deficiency in pediatrics have become increasingly apparent and extend beyond skeletal health. Unfortunately, vitamin D deficiency is highly prevalent in atopic pediatric patients, in whom it may disrupt the immune system and induce significant worsening of reactive airways. This review presents evidence that lung development and immune regulatory functions are vitamin D-dependent. We also review clinical studies that explore how vitamin D supplementation may prevent respiratory infections and help improve asthma control, and we elaborate how these effects may vary among populations. We reveal the strong need of screening measures for vitamin D deficiency in high risk pediatric populations, particularly African-Americans, Hispanic-Americans, and children with obesity. Finally, we emphasize that all children, especially those who are asthmatic, should be assessed to ensure adequate intake or supplementation with at least the minimum recommended doses of vitamin D. The simple intervention of vitamin D supplementation may provide significant clinical improvement in atopic disease, especially asthma.