Serum vitamin D levels and markers of severity of childhood asthma in Costa Rica

Vitamin D Status and Its Association with the SCORAD Score and Serum LL-37 Level in Korean Adults and Children with Atopic Dermatitis

Background

Vitamin D insufficiency could be associated with the prevalence of atopic dermatitis (AD).

Objective

To examine vitamin D status and the relations between serum 25-hydroxyvitamin D levels, SCORAD score, serum LL-37 level, and body mass index (BMI) in Korean AD patients, and to explore whether these associations differ between adults and children.

Methods

Serum 25-hydroxyvitamin D levels, serum LL-37, and clinical features were analyzed in a total of 72 Korean patients with AD (39 adults and 33 children) and 140 healthy control subjects (70 adults and 70 children).

Results

Serum 25-hydroxyvitamin D levels were significantly reduced in children with AD (15.06±4.64 ng/ml) compared with normal children in the control group (16.25±6.60 ng/ml) (p=0.036). Significant inverse correlations were found between BMI and 25-hydroxyvitamin D level (r=-0.315, p=0.007) and between the SCORAD score and serum LL-37 level (r=-0.3, p=0.011) in the total AD patients.

Conclusion

The results showed that serum vitamin D levels were lower in children with AD than in healthy children; however, the same relation was not observed between adults with AD and healthy adults. Serum 25-hydroxyvitamin D concentration was not significantly correlated with AD severity or serum LL-37 levels in our study population.

Vitamin D levels and status amongst asthmatic and non-asthmatic adolescents in Cyprus: a comparative cross-sectional study

BACKGROUND

Emerging evidence suggests that vitamin D might be implicated in asthma pathophysiology. This study aims to compare Vitamin D mean serum levels and status between asthmatic and non-asthmatic adolescents and investigate the association of vitamin D with asthma severity.

METHODS

In a cohort of adolescents aged 16-17 years, those reporting wheezing in the past 12 months and Ever asthma on the ISAAC questionnaire were invited to participate and formed the Active Asthmatics group. Controls were selected amongst Never Wheezers/Never Asthmatics (NWNA). Differences in mean 25(OH)D serum levels and vitamin D status between AA and NWNA were examined in multivariate linear and logistic regression models respectively, adjusting for potential confounders. Within AA, differences in vitamin D levels were assessed across asthma severity indicators.

RESULTS

A total of 69 AA and 671 NWNA participated in the study. Unadjusted mean 25(OH)D serum levels were 22.90 (SD 6.41), and 21.15 (SD 5.59) ng/mL in NWNA and AA respectively (p = 0.03). In adjusted models, mean 25(OH)D levels remained significantly lower amongst AA compared to NWNA (adjusted beta coefficient -1.68, 95% CI -3.24, -0.13). Severe (<12 ng/mL), moderate (<25 ng/mL) or insufficient (<30 ng/mL) vitamin D status was more prevalent among AA who were 1.6 times (95% CI 1.01, 2.53) more likely to belong to a lower vitamin D category compared to NWNA. Within AA, there was a negative trend between vitamin D levels and the number of reported asthma severity indicators.

CONCLUSIONS

Levels of vitamin D tend to be lower among asthmatic compared to non-asthmatic children and in those with severe asthma independent of important confounders.

Vitamin D reduces eosinophilic airway inflammation in nonatopic asthma

BACKGROUND

Low levels of vitamin D are associated with asthma severity, airway remodeling, and exacerbation rate increase, especially in nonatopic asthma. Reduced steroid responsiveness or impaired antimicrobial defense might be underlying mechanisms.

OBJECTIVE

We sought to evaluate the effect of vitamin D supplementation on eosinophilic and neutrophilic airway inflammation in patients with nonatopic asthma.

METHODS

In a double-blind, randomized, placebo-controlled trial, we investigated the effect of long-acting vitamin D3 (400,000 IU) on sputum neutrophils and eosinophils in 44 patients with nonatopic asthma with neutrophilic (≥53%) and/or eosinophilic (≥3%) airway inflammation. Sputum induction was performed at baseline and after 9 weeks. Other measurements included questionnaires, blood samples, and pulmonary function.

RESULTS

Treatment with vitamin D did not significantly affect sputum neutrophils or eosinophils compared with treatment with placebo in the total group. Regarding sputum eosinophils, the effect of vitamin D appeared to be dependent on baseline sputum eosinophil levels (interaction P = .015). In patients with eosinophil levels of 26.2% or more (median in patients with sputum eosinophilia, >3%), eosinophils decreased from a median of 41.0% to 11.8% after vitamin D treatment as compared with an increase from 51.8% to 63.3% in patients receiving placebo (P = .034). Vitamin D treatment also resulted in slightly better Asthma Control Questionnaire scores (P = .08).

CONCLUSIONS

Vitamin D supplementation reduced eosinophilic airway inflammation in patients with nonatopic asthma with severe eosinophilic airway inflammation, but did not affect sputum neutrophils. Also, a small effect on asthma control was observed. These findings suggest that vitamin D might have potential as an add-on treatment option in eosinophilic asthma.

25-hydroxy vitamin D levels are associated with childhood asthma in a population-based study in Peru

BACKGROUND

Vitamin D deficiency may be associated with an increased risk of asthma.

OBJECTIVE

We studied the association between 25-hydroxy (25-OH) vitamin D deficiency and asthma prevalence in two Peruvian populations close to the equator but with disparate degrees of urbanization.

METHODS

We conducted a population-based study in 1441 children in two communities in Peru, of which 1134 (79%) provided a blood sample for 25-OH vitamin D analysis.

RESULTS

In these 1134 children, mean age was 14.8 years; 52% were boys; asthma and atopy prevalence was 12% in Lima vs. 3% in Tumbes (P < 0.001) and 59% in Lima vs. 41% in Tumbes (P < 0.001), respectively; and, mean 25-OH vitamin D level was 20.8 ng/mL in Lima vs. 30.1 ng/mL in Tumbes (P < 0.001). Prevalence of 25-OH vitamin D deficiency (< 20 ng/mL) was 47% in Lima vs. 7% in Tumbes (P < 0.001). In multi-variable logistic regression, we found that lower 25-OH vitamin D levels were associated with an increased odds of asthma (OR = 1.7 per each 10 ng/mL decrease in 25-OH vitamin D levels, 95% CI 1.2-2.6; P < 0.01). In stratified analyses, the association between lower 25-OH vitamin D levels and asthma was limited to children with atopy (OR = 2.2, 95% CI 1.3-3.6) and not in those without atopy (OR = 0.9, 95% CI 0.5-2.0). We did not find associations between 25-OH vitamin D levels and other clinical biomarkers for asthma, including exhaled nitric oxide, total serum IgE and pulmonary function.

CONCLUSION AND CLINICAL RELEVANCE

Both asthma and 25-OH vitamin D deficiency were common among children living in Lima (latitude = 12.0 °S) but not among those in Tumbes (3.6 °S). The relationship between 25-OH vitamin D deficiency and asthma was similar in both sites and was limited among children with atopy. Future supplementation trials may need to consider stratification by atopy at the time of design.

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.

Vitamin D, allergies and asthma: focus on pediatric patients

In recent years, the interest of the scientific world towards vitamin D gradually increased, and several studies have been conducted to dissect its possible role in modulating the development/course of allergic diseases. Also, Vitamin D supplementation has been assessed as a beneficial approach for treating allergies in some, but not all studies. We reviewed herein the available and relevant literature concerning the possible links between Vitamin D, its supplementation and allergic diseases. A literature search was made independently by the Authors, identifying articles for a narrative review. As per literature, Vitamin D plays a key role in calcium and phosphate metabolism, and it is essential for bone health in infants, children and adolescents. However, there is presently insufficient evidence to support vitamin D supplementation for prevention or treatment of allergic diseases in infants, children and adolescents, concerning allergic rhinitis, asthma, food allergy and atopic dermatitis.

Vitamin D, asthma prevalence and asthma exacerbations: a large adult population-based study

BACKGROUND

The impact of low vitamin D status on asthma, asthma morbidity and control is unclear. We aimed to investigate in adults the associations between serum 25-hydroxyvitamin D level and prevalent asthma as well as asthma exacerbations.

METHODS

A cohort of Israeli adults aged 22-50 years with documented vitamin D status were extracted from Clalit Health Services (HMO) between July 1, 2008 and July 1, 2012. Among this population, those with physician-diagnosed asthma and asthma exacerbations were identified. Asthma exacerbations were defined as any of the following: prescription for oral corticosteroids, >5 prescriptions for short acting beta agonists and more than four visits to a physician for asthma. Logistic regression models assessed the associations between vitamin D and both asthma and asthma exacerbations.

RESULTS

Approximately 308 000 members with at least one vitamin D measurement were included in the cohort. Among them, 6.9% (21 237) had physician-diagnosed asthma vs 5.7% in the general population. Serum 25-OHD levels across both groups were similar. However, among those with vitamin D deficiency, the odds of having an exacerbation were 25% greater compared to those with levels in the normal range. This association remained significant after controlling for known confounders.

CONCLUSION

While there was no significant association between vitamin D status and physician-diagnosed asthma, there was a strong association with asthma exacerbations. The presented evidence supports vitamin D screening in the subgroup of asthmatics that are uncontrolled and experience recurrent exacerbations.

Relationship between Vitamin D and Childhood Asthma: A Case-Control Study

OBJECTIVE

Studies determining the relationship between serum vitamin D status and childhood asthma have yielded controversial results. Findings indicated that vitamin D deficiency is associated with asthma and airway hyper responsiveness. The aim of this study was to assess the relationship between serum vitamin D status and childhood asthma.

METHODS

Data were obtained from 200 asthmatic children (age 3-12 years) and 200 healthy controls. Serum levels of 25(OH) vitamin D, total IgE, calcium, phosphorus, parathormone (PTH) and eosinophil count were measured in both asthmatic children and healthy controls. Also, the mean values of 25(OH) vitamin D were compared with asthma symptom severities.

FINDINGS

There was a significant decrease in the concentration of serum 25(OH) vitamin D in the asthmatic patients as compared with the controls (20.34±2.8 vs 25.39±4.1 ng/mL, 95%CI: 1.46-3.86, P=0.01). Out of total asthmatic subjects, 40 (20%) were vitamin D sufficient, 48 (24%) were insufficient, and 112 (56%) were deficient. Total IgE concentration was also significantly higher in asthmatic patients having vitamin D deficiency (132.4±20.1 IU/ml, 95%CI: 1.38-3.75, P=0.03). Comparing asthmatic patients with healthy controls, odds of having vitamin D level less than 20ng/mL was 2.47.

CONCLUSION

Our findings suggest that vitamin D deficiency or insufficiency may be positively related to the prevalence of asthma in children.

Serum 25-hydroxyvitamin D levels in relation to lung function and exhaled nitric oxide in children

OBJECTIVE

To investigate the relationship of vitamin D status with lung function and fraction of exhaled nitric oxide (FeNO) in a population sample of children.

STUDY DESIGN

A total of 1315 children aged 5-18 years were evaluated using serum 25-hydroxyvitamin D [25(OH)D] levels, spirometry, a single-breath online FeNO measurement, and questionnaires.

RESULTS

After adjusting for confounders, the mean forced vital capacity was 53.4 mL (SE, 26.5 mL; P = .045), and the mean forced expiratory volume in 1 second was 48.2 mL (SE, 23.6 mL; P = .042) lower for children with insufficient serum 25(OH)D levels (20-29.9 ng/mL) compared with those with sufficient 25(OH)D levels (≥30 ng/mL). The mean difference between children with deficient (<20 ng/mL) and sufficient levels of serum 25(OH)D was 81.9 mL (SE, 26.7 mL; P = .002) for forced vital capacity and 55.2 mL (SE, 23.7 mL; P = .020) for forced expiratory volume in 1 second. There was no significant association between serum 25(OH)D levels and FeNO after adjusting for confounders.

CONCLUSIONS

Our results demonstrate a significant relationship between insufficient serum vitamin D levels and worse lung function in children in the community with a suggested dose-response effect. Our findings also suggest that vitamin D status is not a significant determinant of FeNO in children in the general population.

Impaired T cell activation and cytokine production by calcitriol-primed human B cells

The biologically active form of vitamin D3 , 1, 25-dihydroxyvitamin D3 (calcitriol), is a potent modulator of the immune response. We have shown previously that calcitriol modulates the immunoglobulin response in vitro and in vivo in mice and humans. To analyse the underlying molecular mechanisms we studied whether calcitriol-primed B cells modulate T cell activation and function. Human B cells were stimulated with anti-CD40 and interleukin (IL)-4 in the presence of increasing concentrations of calcitriol. After removal of calcitriol, primed B cells were co-cultured with autologous CD4(+) T cells; the B cell phenotype T cell activation and their consecutive cytokine production were also assessed. Naive T cells co-cultured with calcitriol-primed naive B cells showed a reduced expansion, nuclear factor of activated T cells, cytoplasmic 2 (NFATc2) expression and cytokine production upon restimulation. CD86 expression on B cells after calcitriol priming was identified as an underlying mechanism, as T cell activation and expansion was rescued by activating anti-CD28 antibodies. Our data indicate that calcitriol-primed B cells display an impaired capacity to activate T cells. Taken together, we identified a novel B cell-dependent vitamin D immune regulatory mechanism, namely by decreased co-stimulation of calcitriol-primed B cells.

Efficacy of high-dose vitamin D in pediatric asthma: a systematic review and meta-analysis

CONTEXT

Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes. The benefit of vitamin D supplementation for pulmonary function, symptoms and exacerbations is not well established.

OBJECTIVE

To systematically review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes.

DATA SOURCES

MEDLINE, EMBASE and CENTRAL were searched until January 2014. No date or language restrictions.

STUDY SELECTION

Clinical trials reporting asthma-related respiratory outcomes following vitamin D administration at a dose equal or greater than 500 IU per day were included and reviewed independently by two authors for full systematic review eligibility.

DATA EXTRACTION

Two reviewers independently extracted and verified pre-defined data fields.

RESULTS

We identified five studies that met study eligibility and assessed final data synthesis. The median trial size was 48 participants (range 17-430) and the average daily dose of cholecalciferol ranged from 500 to 2000 IU/day. Overall study methodological quality was high, but some heterogeneity in population and vitamin D dosing regimen was evident. Meta-analysis suggested a statistically significant reduction (RR 0.41, CI 0.27-0.63) in asthma exacerbation with vitamin D therapy.

LIMITATIONS

Due to variability in outcome selection and missing data, it was not possible to perform meta-analysis for pulmonary function testing and asthma symptom scores. Vitamin D-related adverse events were not considered in four of five papers.

CONCLUSIONS

Available evidence from this systematic review suggests that high dose vitamin D may prevent asthma exacerbation. This should be confirmed through larger well-designed randomised controlled trials.

Cord serum 25-hydroxyvitamin D correlates with early childhood viral-induced wheezing

BACKGROUND

There are investigations concluding that reduced vitamin D status in pregnancy, may be a risk factor for the development of allergic outcomes in offspring. However, studies on the relationship between cord levels of 25-hydroxyvitamin D (25[OH]D) and risk of early childhood wheezing and early-onset atopic dermatitis/food allergy are very limited.

OBJECTIVE

To assess the associations between cord blood concentration of 25[OH]D and occurrence of the incidence of wheezing, atopic dermatitis, food allergy, during the first two years of life.

METHODS

We evaluated 240 children by the age of 2 years from the Polish Mother and Child Cohort Study. Women were interviewed during pregnancy to collect demographic and socioeconomic data, the medical and reproductive history. At delivery, umbilical cord blood plasma was sampled. The child's health status were examined at approximately 2 years. In the analyses multivariable model was used.

RESULTS

Data from 190 participants were included into the analysis. The median value and quartile range of 25[OH]D in cord blood [ng/ml] were as follows: 6.33, 4.16-8.53. 25[OH]D in cord blood below lower quartile increases the risk of multi-triggered wheezing (MTW) in children during first 2 years of life (OR: 2.81; 95% CI: 1.13-7.00). Higher cord serum level of 25[OH]D reduces the risk of viral induced wheezing (VIW). The cord serum level of 25[OH]D below median value (OR: 6.06; 95% CI: 1.3-28.3) or below lower quartile (OR: 5.43; 95% CI: 1.66-17.7) increases the risk of VIW. All above effects of vitamin D level in cord blood were corrected for the effects other independent risk factors of wheezing and VIW in this cohort.

CONCLUSIONS

Cord serum 25[OH]D levels were inversely associated with the risk of multi-triggered wheezing, and especially viral-induced wheezing by the age of 2 years, but no association was found with food allergy, atopic dermatitis and frequencies of infections.

Vitamin D receptor ApaI a allele is associated with better childhood asthma control and improvement in ability for daily activities

Vitamin D levels have been suggested as a marker of disease severity in asthmatic children. Our aim was to investigate possible associations between the vitamin D receptor (VDR) FokI, BsmI, ApaI, and TaqI polymorphisms and asthma susceptibility and control in children. 127 Greek children with asthma and 91 healthy controls were genotyped for VDR FokI, BsmI ApaI, and TaqI polymorphisms using Sequenom MassARRAY iPLEX platform. Asthma control was assessed according to the Global Initiative for Asthma guidelines (GINA) and Childhood Asthma Control Test (C-ACT) and, for the first time, tested for its possible association with VDR SNPs. Asthmatic children were grouped as "controlled (n=49)", "partially controlled (n=38)," and "uncontrolled (n=40)," according to GINA classification. No association was found between VDR polymorphisms and asthma prevalence. Asthmatic children with the VDR ApaI aa genotype had significantly higher C-ACT score compared with asthmatic children carrying the AA/AC VDR ApaI genotypes (p=0.011). The frequency of VDR ApaI aa genotype was significantly higher in controlled asthma group (n=92) than uncontrolled asthma group (n=35), according to C-ACT (24.5% vs 0.0%, p<0.001) and GINA (32.7% vs 7.5%, p=0.001). Also, VDR ApaI aa genotype was negatively associated with limitation in daily activities because of asthma (p=0.004). VDR ApaI aa genotype was positively associated with well-controlled asthma according to GINA and C-ACT questionnaire and negatively associated with decreased limitation in daily activities in asthmatic children, further supporting the importance of Vitamin D pathway in asthma.

Vitamin d levels in children with bronchial asthma

INTRODUCTION

Bronchial Asthma is a common chronic inflammatory disorder of the airways in childhood. Vitamin-D, required for bone mineralization, is also a potent immune system regulator having a potential role in various allergic diseases. This study was undertaken to determine the difference in serum levels of Vitamin-D in asthmatic children and to determine the association between vitamin-D and asthma in children.

MATERIALS AND METHODS

This cross-sectional study included 88 (44 asthmatic children and 44 healthy controls) children aged between 5 and 13 y. Serum 25-hydroxy vitamin-D levels were determined and compared between the two groups. The association between vitamin-D levels and lung function was studied in the asthmatic children.

RESULTS

Serum vitamin-D level was significantly lower in asthmatic children than in control group and in the asthmatic group, vitamin-D levels had a significant positive correlation with FEV1% and FEV1/FVC%.

CONCLUSION

Vitamin-D deficiency is highly prevalent in asthmatic children and is associated with airway limitation.

Vitamin D supplementation blocks pulmonary structural and functional changes in a rat model of perinatal vitamin D deficiency

Whereas epidemiological data strongly link vitamin D (VD) deficiency to childhood asthma, the underlying molecular mechanisms remain unknown. Although VD is known to stimulate alveolar epithelial-mesenchymal interactions, promoting perinatal lung maturation, whether VD supplementation during this period protects against childhood asthma has not been demonstrated experimentally. Using an in vivo rat model, we determined the effects of perinatal VD deficiency on overall pulmonary function and the tracheal contraction as a functional marker of airway contractility. One month before pregnancy, rat dams were put on either a no cholecalciferol-added or a 250, 500, or 1,000 IU/kg cholecalciferol-added diet, which was continued throughout pregnancy and lactation. At postnatal day 21, offspring plasma 25(OH)D levels and pulmonary function (whole body plethysmography and tracheal contraction response to acetylcholine) were determined. 25(OH)D levels were lowest in the no cholecalciferol-supplemented group, increasing incrementally in response to cholecalciferol supplementation. Compared with the 250 and 500 IU/kg VD-supplemented groups, the no cholecalciferol-supplemented group demonstrated a significant increase in airway resistance following methacholine challenge. However, the cholecalciferol deficiency-mediated increase in tracheal contractility in the cholecalciferol-depleted group was only blocked by supplementation with 500 IU/kg cholecalciferol. Therefore, in addition to altering alveolar epithelial-mesenchymal signaling, perinatal VD deficiency also alters airway contractility, providing novel insights to asthma pathogenesis in perinatally VD-deficient offspring. Perinatal VD supplementation at 500 IU/kg appears to effectively block these effects of perinatal VD deficiency in the rat model used, providing a strong clinical rationale for effective perinatal VD supplementation for preventing childhood asthma.

Vitamin D deficiency induces Th2 skewing and eosinophilia in neonatal allergic airways disease

BACKGROUND

Associations between vitamin D status and childhood asthma are increasingly reported, but direct causation and mechanisms underlying an effect remain unknown. We investigated the effect of early-life vitamin D deficiency on the development of murine neonatal allergic airways disease (AAD).

METHODS

In utero and early-life vitamin D deficiency was achieved using a vitamin D-deficient diet for female mice during the third trimester of pregnancy and lactation. Offspring were weaned onto a vitamin D-deficient or vitamin D-replete diet, and exposure to intranasal house dust mite (HDM) or saline was commenced from day 3 of life for up to 6 weeks, when airway hyper-responsiveness (AHR), airway inflammation and remodelling were assessed.

RESULTS

Neonatal mice that had in utero and early-life vitamin D deficiency had significantly increased pulmonary CD3(+) CD4(+) T1ST2(+) cells and reduced CD4(+) IL-10(+) cells. This effect was enhanced following HDM exposure. AHR in HDM-exposed mice was unaffected by vitamin D status. Introduction of vitamin D into the diet at weaning resulted in a significant reduction in serum IgE levels, reduced pulmonary eosinophilia and peri-bronchiolar collagen deposition.

CONCLUSION

Peri-natal vitamin D deficiency alone has immunomodulatory effects including Th2 skewing and reduced IL-10-secreting T regulatory cells, exaggerated with additional allergen exposure. Vitamin D deficiency in early life does not affect AHR, but contributes to disease severity with worse eosinophilic inflammation and airway remodelling. Importantly, supplementation with vitamin D improves both of these pathological abnormalities.

Oral vitamin D increases the frequencies of CD38+ human B cells and ameliorates IL-17-producing T cells

Vitamin D deficiency (serum 25-hydroxyvitamin D < 50 nm) has been associated with the onset of immunological diseases including atopic dermatitis (AD), cutaneous or systemic lupus erythematosus and allergic asthma. In this study, we assessed whether oral vitamin D (cholecalciferol) supplementation leads to a systemic modulation of the phenotype of circulating lymphocyte populations and whether a defined serum 25-hydroxyvitamin D (25(OH)D) concentration can be related to the effects on lymphocytes. Cholecalciferol was administered in a dose-escalation setting to vitamin D-deficient individuals from 2000 up to 8000 IU daily for 12 weeks. Individuals without cholecalciferol intake served as controls. Peripheral B cells and T cells were examined by multicolour flow cytometric analysis. The mean serum 25(OH)D concentrations increased upon cholecalciferol intake up to 159 ± 28.7 nm, and remained low in the control group 30.0 ± 12.5 nm. Following cholecalciferol intake, the frequencies of circulating CD38 expressing B cells were significantly increased and IFN-γ+ , and/or IL-17+ CD4+ T helper cells were decreased. These data were identified to correlate with the serum 25(OH)D levels by applying two different analysis approaches (ROC and a nonlinear regression analysis). Our data indicate that increasing 25(OH)D serum concentrations are associated with an increased expression of CD38 on B cells and a decreased T-cell-dependent proinflammatory cytokine production. The therapeutical role of our findings in systemic immunological diseases should be explored in the future by further controlled clinical studies.

Serum 25-hydroxyvitamin D levels are lower in chronic rhinosinusitis with nasal polyposis and are correlated with disease severity in Taiwanese patients

BACKGROUND

Vitamin D deficiency is reported to be associated with increased incidence of allergic airway diseases and is correlated with the severity of asthma. This study was designed to determine if serum Vitamin D level is lower in chronic rhinosinusitis with nasal polyposis (CRSwNP) patients and if low serum Vitamin D level is correlated with the severity of CRSwNP.

METHODS

New CRSwNP patients undergoing elective endoscopic sinus surgery were recruited. Patients with malignancies or asthma were excluded. Twenty chronic rhinosinusitis without nasal polyposis (CRSsNP) patients were used as control. Demographic characteristic information was collected. The severity of CRSwNP was assessed with the Lund-Mackay (LM) score and polyp grading system. Vitamin D status was assessed by measuring circulating 25-hydroxyvitamin D (25OHD) by using commercial chemiluminescence immunoassay. Data were stratified by factors known to affect serum 25OHD, including sex, race, and body mass index.

RESULTS

Serum 25OHD levels (ng/mL ± SD) were significantly lower in patients with CRSwNP (21.4 ± 5.7) than in those with CRSsNP (28.8 ± 6.2; p < 0.001). The incidences of vitamin D deficiency (<20 ng/mL) in CRSwNP and CRSsNP patients were 45.5 and 6.3%; however, the incidences of vitamin D insufficiency (20-30 ng/mL) in these patients were 50.0 and 62.5%, respectively. A significantly negative relationship was found between serum 25OHD level and polyp grade (r = -0.63; p = 0.001), indicating lower serum 25OHD was associated with higher polyp grade. Serum 25OHD was inversely related to both LM score and total IgE level as well; however, statistical significance was not found.

CONCLUSION

A significantly lower vitamin D level was found in a group of Taiwanese CRSwNP patients, which revealed an association with greater nasal polyp size. Serum vitamin D levels could be added to the routine workup of patients suffering from CRS and these data could be used to potentially help determine the disease severity.

Asthma in the elderly: a study of the role of vitamin D

Background

Asthma in the elderly is poorly understood and vitamin D deficiency and insufficiency are very common in older individuals. We studied the role of vitamin D in elderly asthmatics.

Methods

Asthmatics subjects, age 65 and older, were followed every 4 weeks for 12 weeks in the late fall and winter. During the study period they took 2,000 I.U. vitamin D3 daily. Serum 25-Hydroxyvitamin D and calcium were measured at baseline and study end.

Results

Twenty nine percent of subjects were deficient and 50% insufficient in serum vitamin D at baseline. Serum vitamin D increased from 24.3±9.2 ng/ml (60.7±23 nmol/L) to 34±7.1 ng/ml (84.9±17.7 nmol/L) at the end of the study (p<0.001), whereas calcium was unchanged. We found no significant association between vitamin D and subjects' demographics. Vitamin D was similar in men and women. There was no association between serum vitamin D and inhaled steroid dose. Vitamin D was significantly lower in subjects with uncontrolled asthma (Asthma Control Test, ACT≤19) compared to the ones with well controlled symptoms (p<0.05). In subjects with uncontrolled asthma at baseline, ACT scores increased significantly at the end of the study (p<0.04), but not at 4 and 8 weeks. Spirometric values remained unchanged throughout the study.

Conclusions

Elderly asthmatics very commonly have vitamin D deficiency or insufficiency. Serum vitamin D levels were lower in subjects with uncontrolled asthma. In these subjects, vitamin D supplementation for 12 weeks led to improved ACT scores. Larger, randomized, placebo controlled studies are required to further evaluate whether vitamin D supplementation may improve asthma symptoms in this population.

Trial registration

ClinicalTrials.gov NCT01730976.

Vitamin D and asthma-life after VIDA?

The vitamin D hypothesis postulates that lower vitamin D levels are causally associated with increased asthma risk and asthma severity. Multiple epidemiological studies have shown an inverse relationship between circulating vitamin D levels (in the form of 25-hydroxy vitamin D) and asthma severity and control and lung function. However, in the recently published vitamin D and asthma (VIDA) study, vitamin D supplementation failed to show an improvement in asthma control in adults. This article reviews the current epidemiological and trial evidence for vitamin D and asthma and explores some of the possible alternative explanations for previous findings (including "reverse causation" and the importance of studying children and adults). We also address some of the unique challenges of conducting vitamin D trials and potential ways to address them. Finally, I will argue for further clinical trials of vitamin D in asthma, especially in children, using knowledge gained from the VIDA trial.

Is vitamin D insufficiency to blame for recurrent wheezing?

BACKGROUND

Vitamin D (VitD) and its metabolites play important roles in the regulation of the respiratory and immune systems. The aim of this study was to examine serum 25(OH) vitamin D [25(OH)D] levels and VitD deficiency on the development of wheezing and clinical features.

METHODS

This study was a prospective cross-sectional survey that included a total of 70 infants being followed in the Pediatric Immunology and Allergy Unit at Ondokuz Mayis University. Forty of these infants (patient group), ranging in age from 1 to 3 years, had been diagnosed as wheezy infants; 30 were age-and-gender matched healthy infants (control group). Prior to the study, blood samples were taken from both groups to determine their serum VitD, blood eosinophil, and serum immunoglobulin E (IgE) levels.

RESULTS

The duration of breastfeeding was similar for both groups. The serum 25(OH)D levels of the patient group were significantly lower than those of the control group. Although there was a negative relationship between 25(OH)D level and IgE(log10) values for the wheezy infants with VitD deficiency, the control group had a negative relationship between VitD level and IgE(log10) .

CONCLUSION

Serum 25(OH)D levels must be evaluated when following wheezy infants, and those with deficiency must be treated with VitD.

Vitamin D and Its Role as a Protective Factor in Allergy

The relationship between vitamin D status and asthma has been subject to several studies in the last decade. Epidemiological data suggest that incidence of asthma and atopic diseases increased significantly in most Westernized countries. The significant variation between countries suggests that besides genetic factors, environmental aspects play a role in the pathogenesis of atopy. The prevalence of hypovitaminosis D is high in many industrialized countries. In addition to its relationship with bone metabolism, vitamin D is recognized as an immunomodulator, with important effects on both adaptive and innate immunity. Correlations between vitamin D status and asthma have been formulated, with a considerable interest in assessing whether this vitamin protects against or reduces asthma morbidity. In this review, we discuss recent findings regarding vitamin D status throughout Europe and its influence over asthma and allergic rhinitis prevalence. Geographical latitude and dietary habits may explain the lower prevalence of allergic disease in Albania. We also consider the effects of vitamin D supplementation in allergic disease. Several clinical trials are under way and their results are needed in order to make definitive recommendations about the optimal dose of vitamin D for prevention and treatment of asthma and allergic disease.

Vitamin E and D regulation of allergic asthma immunopathogenesis

Asthma occurs as complex interactions of the environmental and genetics. Clinical studies and animal models of asthma indicate dietary factors such as vitamin E and vitamin D as protective for asthma risk. In this review, we discuss opposing regulatory functions of tocopherol isoforms of vitamin E and regulatory functions of vitamin D in asthma and how the variation in global prevalence of asthma may be explained, at least in part, by these dietary components.

The effects of vitamin D supplementation on airway functions in mild to moderate persistent asthma

BACKGROUND

Vitamin D is hypothesized to have some roles in innate and adaptive immunity, inflammation reduction, and remodeling; therefore, it is supposed to affect the asthma phenotype, severity, and response to inhaled corticosteroid (ICS).

OBJECTIVE

To explore the synergistic effects of vitamin D supplementation in addition to asthma controllers (ICS or ICS plus long-acting β-agonist) on airway functions.

METHODS

A randomized clinical trial was conducted in 130 individuals aged 10 to 50 years who lived in Tehran during a 24-week period. Data on age, sex, body mass index, stage of asthma, serum total IgE, history of allergic rhinitis, atopic dermatitis, food allergy, and urticaria were collected. Spirometric parameters (forced expiratory volume in 1 second [FEV1] and ratio of FEV1 to forced vital capacity) and serum vitamin D measurement were obtained before and 8 and 24 weeks after the intervention. Patients were divided in 2 groups randomly. Both groups received asthma controllers (budesonide or budesonide plus formoterol) according to their stage, but the intervention group received vitamin D supplementation (100,000-U bolus intramuscularly plus 50,000 U orally weekly) in addition to asthma controllers.

RESULTS

FEV1 improved significantly in both groups after 8 weeks, but no significant difference was found between the 2 groups at baseline (P = .20) or after 8 weeks (P = .99); however, a significant improvement was seen in the intervention group in the last 16 weeks, and FEV1 was significantly better in the intervention group than the other group after 24 weeks (P < .001).

CONCLUSION

Vitamin D supplementation associated with asthma controllers could significantly improve FEV1 in mild to moderate persistent asthma after 24 weeks.

TRIAL REGISTRATION

irct.ir Identifier: IRCT201302079608N1.

Cigarette smoke exposure is associated with vitamin D3 deficiencies in patients with chronic rhinosinusitis

BACKGROUND

Cigarette smoke (CS) plays a role in the exacerbation of chronic rhinosinusitis (CRS); however, the mechanism for this is unknown. We hypothesize that CS impairs human sinonasal epithelial cell (HSNEC) conversion of 25(OH)D3 (25VD3) to 1,25-dihydroxyvitamin D3 (1,25VD3) and, furthermore, that supplementation with 1,25VD3 will reverse smoke-induced inflammatory responses by HSNECs.

OBJECTIVE

We sought to determine the effect of CS on vitamin D3 (VD3) levels, conversion, and regulation of CS-induced inflammation in control subjects and patients with CRS.

METHODS

Blood and sinus tissue explants were collected at the time of surgery from control subjects, patients with chronic rhinosinusitis without nasal polyps, and patients with chronic sinusitis with nasal polyps (CRSwNP). Expression of VD3 metabolizing enzymes were measured by using RT-PCR. Primary HSNECs were cultured from tissue explants. 25VD3 with and without cigarette smoke extract (CSE) was used to examine conversion of 25VD3 to 1,25VD3, as well as HSNEC production of proinflammatory cytokines.

RESULTS

CS exposure was associated with reduced circulating and sinonasal 25VD3 levels in all groups compared with those seen in CS-naive, disease-matched counterparts. CS exposure decreased expression of CYP27B1 and was especially pronounced in patients with CRSwNP. CSE impairs control HSNEC conversion of 25VD3. HSNECs from patients with CRSwNP also demonstrate an intrinsic reduction in conversion of 25VD3 to 1,25VD3. Exogenous 1,25VD3 reduces CSE-induced cytokine production by HSNECs.

CONCLUSIONS

Exposure to CS is associated with reduced 25VD3 levels and an impaired ability of HSNECs to convert 25VD3 to 1,25VD3. Addition of 1,25VD3 reduces the proinflammatory effects of CS on HSNECs. Impaired VD3 conversion by CS exposure represents a novel mechanism through which CS induces its proinflammatory effects.

Vitamin D in inflammatory diseases

Changes in vitamin D serum levels have been associated with inflammatory diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis (MS), atherosclerosis, or asthma. Genome- and transcriptome-wide studies indicate that vitamin D signaling modulates many inflammatory responses on several levels. This includes (i) the regulation of the expression of genes which generate pro-inflammatory mediators, such as cyclooxygenases or 5-lipoxygenase, (ii) the interference with transcription factors, such as NF-κB, which regulate the expression of inflammatory genes and (iii) the activation of signaling cascades, such as MAP kinases which mediate inflammatory responses. Vitamin D targets various tissues and cell types, a number of which belong to the immune system, such as monocytes/macrophages, dendritic cells (DCs) as well as B- and T cells, leading to individual responses of each cell type. One hallmark of these specific vitamin D effects is the cell-type specific regulation of genes involved in the regulation of inflammatory processes and the interplay between vitamin D signaling and other signaling cascades involved in inflammation. An important task in the near future will be the elucidation of the regulatory mechanisms that are involved in the regulation of inflammatory responses by vitamin D on the molecular level by the use of techniques such as chromatin immunoprecipitation (ChIP), ChIP-seq, and FAIRE-seq.

Association of vitamin D with respiratory outcomes in Canadian children

BACKGROUND/OBJECTIVES

Vitamin D modifies airway inflammation and appears to be important in building immunity against respiratory infections, and so is potentially beneficial in asthma. However, to date results from studies investigating the relationship of vitamin D with respiratory outcomes are inconsistent. The objective of this study was to determine the association of vitamin D with current wheeze, ever asthma and lung function.

SUBJECTS/METHODS

Data on 1213 children aged 6-12 years, from the Canadian Health Measures Survey, were considered for the study. Serum 25-hydroxy vitamin D (25(OH)D) levels were categorized into three categories: ⩽49 nmol/l (low); 50-74 nmol/l (moderate); and ⩾75 nmol/l (high).

RESULTS

Children in the low and high 25(OH)D categories were more likely to report current wheeze in comparison to those in the moderate category (odds ratio (OR): 3.26, 95% confidence interval (CI): 1.16-9.17 and OR: 2.14, 95% CI: 1.07-4.28, respectively). The results for the association between 25(OH)D levels and ever asthma were similar to those observed for current wheeze, except that a significant association was observed only in the lower category. The rate of increase in forced expiratory volume in one second and forced vital capacity with age was greater in the moderate category.

CONCLUSIONS

Children in both low and high 25(OH)D categories had increased risk of current wheeze and reduced rate of change in lung function with age in comparison to the moderate category, raising the possibility of a U-shaped association between vitamin D levels and respiratory health. Clearer guidelines for optimal vitamin D levels are required to improve respiratory health in children.

Serum 25 hydroxy vitamin D insufficiency associated with bronchial asthma in Lucknow, India

OBJECTIVES

To assess the association between serum 25 hydroxy vitamin D levels and asthma and its control in Indian children.

METHODS

This was a prospective case-control study conducted in tertiary care hospital. Cases of asthma and healthy age-matched controls were included, aged 1-15 y, who had not received any vitamin D supplementation in the last year and had no other co-morbidity, after obtaining written informed parental consent. 25 hydroxy vitamin D insufficiency was taken below level of ≤ 30 ng/mL.

RESULTS

Fifty asthmatics and 25 age-matched controls were recruited from August 2011-July 2012. 25 hydroxy vitamin D insufficiency was associated with occurrence of asthma (OR = 13.5; 95 % CI = 4.25-42.85: p = 0.000). With decreasing level of asthma control there was increasing strength of association with 25 hydroxy vitamin D insufficiency [χ (2) for trend = 24.96 (p = 0.000)].

CONCLUSIONS

25 hydroxy vitamin D insufficiency is associated with bronchial asthma as well as its level of control.

25-Hydroxyvitamin D, IL-31, and IL-33 in children with allergic disease of the airways

Low vitamin D is involved in allergic asthma and rhinitis. IL-31 and IL-33 correlate with Th2-associated cytokines in allergic disease. We investigated whether low vitamin D is linked with circulating IL-31 and IL-33 in children with allergic disease of the airways. 25-Hydroxyvitamin D [25(OH) Vit D], IL-31, and IL-33 plasma levels were measured in 28 controls (HC), 11 allergic rhinitis (AR) patients, and 35 allergic asthma with rhinitis (AAR) patients. We found significant lower levels of 25(OH) Vit D in AR and in AAR than in HC. IL-31 and IL-33 plasma levels significantly increased in AAR than HC. IL-31 and IL-33 positively correlated in AR and AAR. 25(OH) Vit D deficient AAR had higher levels of blood eosinophils, exacerbations, disease duration, and total IgE than patients with insufficient or sufficient 25(OH) Vit D. In AAR 25(OH) Vit D levels inversely correlated with total allergen sIgE score and total atopy index. IL-31 and IL-33 did not correlate with 25(OH) Vit D in AR and AAR. In conclusion, low levels of 25(OH) Vit D might represent a risk factor for the development of concomitant asthma and rhinitis in children with allergic disease of the airways independently of IL-31/IL-33 Th2 activity.

25-hydroxvitamin D3 promotes the long-term effect of specific immunotherapy in a murine allergy model

Calcitriol (1α,25-dihydroxyvitamin D3) is the active vitamin D metabolite and mediates immunological functions, which are relevant in allergy. Its therapeutic use is limited by hypercalcaemic toxicity. We have previously shown that the activation of the vitamin D receptor inhibits IgE production and that B cells can synthesize calcitriol from its precursor 25-hydroxyvitamin D3 (inactive precursor) [25(OH)D] upon antigenic stimulation. In this study, we address the impact of 25(OH)D on the development of type I sensitization and determine its role in allergen-specific immunotherapy. BALB/c mice were sensitized to OVA, under 25(OH)D-deficient or sufficient conditions. The humoral immune response over time was measured by ELISA. OVA-specific immunotherapy was established and studied in a murine model of allergic airway inflammation using lung histology, pulmonary cytokine expression analysis, and functional parameters in isolated and perfused mouse lungs. In 25(OH)D-deficient mice, OVA-specific IgE and IgG1 serum concentrations were increased compared with control mice. OVA-specific immunotherapy reduced the humoral immune reaction after OVA recall dose-dependently. Coadministration of 25(OH)D in the context of OVA-specific immunotherapy reduced the allergic airway inflammation and responsiveness upon OVA challenge. These findings were paralleled by reduced Th2 cytokine expression in the lungs. In conclusion, 25(OH)D deficiency promotes the development of type I sensitization and correction of its serum concentrations enhances the benefit of specific immunotherapy.

Novel drug targets for asthma and COPD: lessons learned from in vitro and in vivo models

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent respiratory diseases characterized by airway inflammation, airway obstruction and airway hyperresponsiveness. Whilst current therapies, such as β-agonists and glucocorticoids, may be effective at reducing symptoms, they do not reduce disease progression. Thus, there is a need to identify new therapeutic targets. In this review, we summarize the potential of novel targets or tools, including anti-inflammatories, phosphodiesterase inhibitors, kinase inhibitors, transient receptor potential channels, vitamin D and protease inhibitors, for the treatment of asthma and COPD.

Defining severe asthma - an approach to find new therapies

Asthma is a chronic inflammatory disease that has reached epidemic proportions worldwide. It is treatable in the majority of patients, but there is no cure. Moreover, a proportion of patients suffer from severe, difficult-to-control disease with daily symptoms and high morbidity, making it imperative that we continue to improve our understanding of the underlying mechanisms of this disease. Severe asthma is a heterogeneous condition. A systematic approach to identify specific asthma phenotypes, including clinical characteristics and inflammatory processes, is the first step toward individualized, logical therapy. This review focuses on the need to characterize severe asthma phenotypes and on novel, targeted molecular treatment options currently under development.

Asthma in Hispanics. An 8-year update

This review provides an update on asthma in Hispanics, a diverse group tracing their ancestry to countries previously under Spanish rule. A marked variability in the prevalence and morbidity from asthma remains among Hispanic subgroups in the United States and Hispanic America. In the United States, Puerto Ricans and Mexican Americans have high and low burdens of asthma, respectively (the "Hispanic Paradox"). This wide divergence in asthma morbidity among Hispanic subgroups is multifactorial, likely reflecting the effects of known (secondhand tobacco smoke, air pollution, psychosocial stress, obesity, inadequate treatment) and potential (genetic variants, urbanization, vitamin D insufficiency, and eradication of parasitic infections) risk factors. Barriers to adequate asthma management in Hispanics include economic and educational disadvantages, lack of health insurance, and no access to or poor adherence with controller medications such as inhaled corticosteroids. Although considerable progress has been made in our understanding of asthma in Hispanic subgroups, many questions remain. Studies of asthma in Hispanic America should focus on environmental or lifestyle factors that are more relevant to asthma in this region (e.g., urbanization, air pollution, parasitism, and stress). In the United States, research studies should focus on risk factors that are known to or may diverge among Hispanic subgroups, including but not limited to epigenetic variation, prematurity, vitamin D level, diet, and stress. Clinical trials of culturally appropriate interventions that address multiple aspects of asthma management in Hispanic subgroups should be prioritized for funding. Ensuring high-quality healthcare for all remains a pillar of eliminating asthma disparities.

Anti-inflammatory and corticosteroid-enhancing actions of vitamin D in monocytes of patients with steroid-resistant and those with steroid-sensitive asthma

BACKGROUND

Vitamin D is known for its anti-inflammatory effects.

OBJECTIVE

Vitamin D regulation of responses in patients with steroid-resistant (SR) versus steroid-sensitive (SS) asthma has not been studied.

METHODS

Peripheral blood cells from 11 patients with SR asthma and 8 patients with SS asthma were preincubated with 1,25-dihydroxyvitamin D (1,25[OH]2D [VitD]), followed by dexamethasone (DEX) treatment and LPS stimulation. LPS-induced phosphorylated p38 mitogen-activated protein kinase (p-p38) in monocytes was examined by means of flow cytometry. Mitogen-activated protein kinase phosphatase-1 (MKP-1) mRNA expression, which inhibits p-p38, was analyzed by means of real-time PCR. Glucocorticoid receptor (GR) binding and histone H4 acetylation in the glucocorticoid response element of the MKP-1 promoter in monocytes were analyzed by means of chromatin immunoprecipitation.

RESULTS

DEX significantly inhibited LPS-induced p-p38 in monocytes from patients with SS asthma but not those from patients with SR asthma (P < .01). VitD inhibited LPS-induced p-p38 in monocytes from both patient groups (P < .01) but enhanced DEX suppression of LPS-induced p-p38 only in monocytes from patients with SS asthma (P < .01). VitD induced MKP-1 expression and enhanced DEX induction of MKP-1 in both patients with SS asthma and patients with SR asthma. VitD/DEX-induced MKP-1 mRNA levels remained significantly lower in monocytes from patients with SR asthma (P < .05). DEX-stimulated recruitment of GR and histone H4 acetylation at the glucocorticoid response element 4.6 kbp upstream of the MKP-1 gene were significantly lower in monocytes from patients with SR asthma compared with those from patients with SS asthma. VitD pretreatment enhanced DEX-induced GR binding and histone acetylation in monocytes from both patient groups. However, GR binding and histone H4 acetylation remained significantly lower in monocytes from patients with SR asthma.

CONCLUSION

VitD demonstrated anti-inflammatory and corticosteroid-enhancing effects in monocytes of patients with SR asthma and patients with SS asthma. However, the responses to corticosteroids in patients with SR asthma remained significantly lower than those in patients with SS asthma.

Effect of vitamin D-binding protein genotype on the development of asthma in children

BACKGROUND

Potential vitamin D-related influences on inflammatory diseases such as asthma are controversial, including the suggestion that vitamin D insufficiency is associated with increased asthma morbidity. Vitamin D-binding protein transports vitamin D metabolites in the circulation. Single nucleotide polymorphisms in the GC gene encoding vitamin D-binding protein are associated with circulating vitamin D metabolite levels in healthy infants and toddlers.

OBJECTIVE

To test the hypothesis that GC single nucleotide polymorphisms encoding the D432E and T436K variants predict subsequent development of asthma in healthy children.

METHODS

A retrospective medical record review was performed to determine the development of asthma in 776 children in whom GC genotype, vitamin D-binding protein concentration, and circulating 25-hydroxyvitamin D had been determined at 6 to 36 months of age. Demographic and detailed current clinical data were collected and criteria for asthma were recorded.

RESULTS

GC genotype was available for 463 subjects. After an initial analysis of all subject data, the analysis was limited to the predominant Hispanic population (72.1%) to minimize potential confounding effects of ethnicity. Asthma was diagnosed in 87 children (26%). Subjects with the GC genotype encoding the ET/ET (Gc1s/Gc1s) variant had lower odds of developing asthma, representing a protective effect compared with subjects with the DT/DT (Gc1f/Gc1f) variant.

CONCLUSION

In the Hispanic population of inner-city New Haven, Connecticut, the ET/ET (Gc1s/Gc1s) genotype of vitamin D-binding protein might confer protection against the development of asthma compared with the wild-type genotype DT/DT (Gc1f/Gc1f).

Vitamin D and inflammatory diseases

Beyond its critical function in calcium homeostasis, vitamin D has recently been found to play an important role in the modulation of the immune/inflammation system via regulating the production of inflammatory cytokines and inhibiting the proliferation of proinflammatory cells, both of which are crucial for the pathogenesis of inflammatory diseases. Several studies have associated lower vitamin D status with increased risk and unfavorable outcome of acute infections. Vitamin D supplementation bolsters clinical responses to acute infection. Moreover, chronic inflammatory diseases, such as atherosclerosis-related cardiovascular disease, asthma, inflammatory bowel disease, chronic kidney disease, nonalcoholic fatty liver disease, and others, tend to have lower vitamin D status, which may play a pleiotropic role in the pathogenesis of the diseases. In this article, we review recent epidemiological and interventional studies of vitamin D in various inflammatory diseases. The potential mechanisms of vitamin D in regulating immune/inflammatory responses in inflammatory diseases are also discussed.

Relationships between Plasma Micronutrients, Serum IgE, and Skin Test Reactivity and Asthma among School Children in Rural Southwest Nigeria

Objective. Increasing prevalence of asthma has been attributed to changes in lifestyle and environmental exposures. We conducted a case-control study to investigate the relationship between serum micronutrients and asthma in rural school children in Nigeria. Methods. We administered questionnaires to 1,562 children to identify children with asthma. Serum concentration levels of 12 micronutrients were determined in asthma cases (N = 37) and controls (N = 30). Allergy skin prick test and spirometry were also performed. Results. Plasma levels of the following micronutrients were significantly different between cases and controls: calcium (7.48 ± 2.16 versus 8.29 ± 1.62 mg/dL; P = 0.04), manganese (44.1 ± 11.5 versus 49.3 ± 7.9 mg/L; P = 0.01), selenium (76.1 ± 14.9 versus 63.3 ± 26.8 μg/L; P = 0.02), and albumin (3.45 ± 0.90 versus 3.91 ± 0.99 g/dL; P = 0.04). Plasma concentrations of iron and selenium were positively correlated with lung function, r = 0.43 (P < 0.05 in each case) while manganese serum concentration was negatively correlated with asthma (r = −0.44; P < 0.05). Conclusions. Children with asthma had reduced levels of plasma manganese, calcium, and albumin but raised level of selenium. The protective or risk effects of these micronutrients on asthma warrant further investigation.

Vitamin D deficiency and level of asthma control in women from North of Jordan: a case-control study

INTRODUCTION

Reduced vitamin-D levels in patients with asthma have been associated with impaired lung function, increased airway hyper-responsiveness, and reduced glucocorticoid responsiveness. Nationwide studies revealed a considerable prevalence of vitamin-D deficiency (VDD) in Jordanian women.

OBJECTIVE

A case-control study was conducted to determine the relationship between serum vitamin A and D levels and asthma among women in North of Jordan.

METHODS

Sixty-eight asthmatics, age range between 14 and 65 years and 77 healthy women, age range between 19 and 51 years, were enrolled. Asthma severity was classified using Global Initiative for Asthma (GINA) guidelines and Asthma Control Test (ACT) questionnaire. Serum vitamin-A and 25-hydroxyvitamin-D (25(OH)D3) levels were measured using high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods, respectively.

RESULTS

The prevalence of VDD (<15 ng/ml) was higher but not statistically significant for women with asthma compared with controls (95.6% vs. 87.0%; p = 0.070). The severity of VDD correlated with the number of asthma medications (p = 0.020). 25(OH)-D3 serum levels directly correlated with asthma control level using ACT score (p = 0.012) and GINA classification (p = 0.046). After adjusting for age, the odds of having VDD for asthmatic women were 35.9 times higher than that for women with no asthma. There was no difference in serum vitamin-A level between healthy and asthmatic women (p = 0.214) and none had vitamin-A deficiency (<200 µg/dl).

CONCLUSIONS

VDD is prevalent in women with asthma in northern Jordan. The severity of VDD correlated with poor asthma control and a need for more medications to control asthma. There was no association between vitamin-A and asthma.

The association between serum vitamin D level and immunoglobulin E in Korean adolescents

OBJECTIVE

Vitamin D has immune modulatory functions, and thus its relationship with allergic disease has been evaluated in a number of studies. However, no concrete link between serum IgE level and vitamin D has been established. Thus, the purpose of study was to confirm the association of serum vitamin D level with the serum IgE (total and Dematophagoides farinae specific IgE) in Korean adolescents.

METHODS

A total of 365 subjects between 10 and 18 years of age were enrolled through the Korea National Health and Nutrition Examination Survey (KNHANES). Serum levels of vitamin D, total IgE, and Dermatophagoides farinae (Df) specific IgE were measured, and data for potential confounding variables were collected. Multivariate regression analyses were used to determine the independent effects of these variables.

RESULTS

Levels of both total and Df specific IgE were positively correlated with serum concentration of vitamin D (Spearman's rho (R)=0.126, p=0.016; R=0.152, p=0.004, respectively). These results were confirmed by multivariate linear regression analysis after adjusting for sex, age, and body mass index (coefficient (B): 10.45 95% confidence interval (CI): 0.59-20.31; B: 1.06, 95% CI: 0.31-1.80, respectively). And, the association between serum vitamin D and IgE showed the different results depending on the presence or absence of Df sensitization.

CONCLUSIONS

Serum concentration of vitamin D was positively associated with levels of both total IgE and Df-specific IgE in Korean adolescents.

Age at onset of asthma and allergen sensitization early in life

BACKGROUND

Epidemiological evidence indicates that the age at onset of asthma and allergen sensitization in early life is decreasing in people from Western countries. To explore latent trends, we conducted a retrospective examination of the age at onset of asthma and specific IgE antibodies against inhalant allergens in Japanese asthmatic children.

METHODS

We conducted a case series study of 103 consecutive children with atopic type of asthma (aged 2 years to 16 years, mean age 9.4 ± 3.4 years). Diagnoses of asthma and allergic rhinitis were defined according to Japanese guidelines. The onset of asthma and allergic rhinitis was also defined as any report of asthma and allergic rhinitis confirmed by a physician. Allergen sensitization was evaluated as specific serum IgE levels for 9 common inhalant allergens in peripheral blood. Atopic type of asthma was defined as a being positive for at least one aeroallergen.

RESULTS

Mean age at asthma onset was 2.3 ± 1.9 years, which is slightly lower than that of previous reports, including those published in Japan. A high prevalence rate of up to 80% was found for perennial antigens including Dermatophagoides spp. and house dust, as reported previously. Notably, some of the children aged at 1 year tested positive for these allergens.

CONCLUSIONS

The age at onset of asthma seems to be decreasing in comparison with previous reports. Furthermore, the age at onset of allergen sensitization against inhalant allergens appears to follow this trend.

Immunoregulatory mechanisms of vitamin D relevant to respiratory health and asthma

Vitamin D deficiency is prevalent among people with various immune-mediated conditions, including autoimmune diseases and asthma. Serum 25(OH)D levels inversely correlate with asthma severity, glucocorticoid responsiveness/dosage, and markers of pathogenesis, such as airway remodeling, IgE, and eosinophilia. Trials involving supplementation with active vitamin D or a precursor are beginning to emerge with variable results that, in part, reflect differences in study design. This review looks at the mechanisms by which vitamin D may protect against asthma, including increasing glucocorticoid responsiveness, skewing immune cells towards a regulatory phenotype, reducing the incidence of infections, airway remodeling, eosinophilia, and lowering the levels of IgE. Also discussed is the therapeutic potential for vitamin D, which is likely to be applicable to immune-mediated conditions beyond simply asthma.

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.

Are asthmatic patients prone to bone loss?

BACKGROUND

Recent studies suggest an association between allergic diseases, including asthma, and lower vitamin D level, a well-known risk factor of osteoporosis. However, it is not yet clearly known whether patients with asthma are prone to bone loss.

OBJECTIVE

To evaluate whether the occurrence of airway hyperresponsiveness (AHR) or asthma is related to significant changes in bone mineral density (BMD).

METHODS

We retrospectively enrolled 7,034 patients who had undergone a health checkup program, including BMD tests and methacholine bronchial challenge tests, at the Seoul National University Hospital, Healthcare System Gangnam Center, from November 1, 2004 to April 30, 2011. Asthma was ascertained by self-reported medical diagnosis by a physician. Patients with a history of systemic corticosteroid medication use were excluded from the study.

RESULTS

Among a total of 7,034 patients, 216 (3.1%) had a positive AHR test result, and 217 (3.1%) had a history of asthma. Lumbar spine and femur BMD of patients with AHR were significantly lower than those without AHR (-0.53 ± 1.50 vs -0.03 ± 1.49, -0.47 ± 0.97 vs -0.22 ± 0.99, respectively; P < .001 for both). After being adjusted for age, sex, body mass index, smoking status, postmenopausal state, and previous history of hormone replacement therapy, the proportion of patients with osteopenia or osteoporosis was much higher in the AHR-positive group than in the AHR-negative group (odds ratio, 1.715; 95% confidence interval, 1.252-2.349) and in the ever-asthma group than in the never-asthma group (odds ratio, 1.526; 95% confidence interval, 1.120-2.079).

CONCLUSION

In the current study, AHR and asthma were related to clinically meaningful BMD decrease, although the causal relationship is unclear.

The association of vitamin D status with cardiometabolic risk factors, obesity and puberty in children

Low serum 25-hydroxyvitamin D3 (25(OH)D) levels have been associated with insulin resistance and cardiovascular diseases. The influences of gender, puberty and adiposity on vitamin D status and the relationship between 25(OH)D and cardiometabolic risk factors in obese and non-obese children were studied. A retrospective analysis was carried out on 168 Turkish children during late winter. Age, gender, puberty, body mass index (BMI), 25(OH)D levels and cardiometabolic risk factors including lipid profiles, high-sensitivity C-reactive protein and insulin resistance index calculated by homeostasis model assessment (HOMA-IR) were evaluated. The median age of the study population was 11 (4-16) years, and 102 children (60.7 %) were prepubertal. Overall, 98.2 % of patients had 25(OH)D levels lower than 20 ng/mL (median 10.0 (4.0-21.3) ng/mL). The 25(OH)D levels did not correlate with BMI. However, an inverse correlation was seen between serum 25(OH)D and HOMA-IR (rho = -0.656, p = 0.006) and insulin (rho = -0.715, p = 0.002) in pubertal obese subjects. Female gender and puberty were all negatively associated with 25(OH)D.

CONCLUSION

The association between vitamin D status and BMI is complex, and it does not seem to be altered by mild obesity. In addition, potential influence of puberty should be kept in mind while assessing the relationship between serum 25(OH)D and cardiometabolic risk factors.

DO IT Trial: vitamin D Outcomes and Interventions in Toddlers - a TARGet Kids! randomized controlled trial

BACKGROUND

Vitamin D levels are alarmingly low (<75 nmol/L) in 65-70% of North American children older than 1 year. An increased risk of viral upper respiratory tract infections (URTI), asthma-related hospitalizations and use of anti-inflammatory medication have all been linked with low vitamin D. No study has determined whether wintertime vitamin D supplementation can reduce the risk of URTI and asthma exacerbations, two of the most common and costly illnesses of early childhood. The objectives of this study are: 1) to compare the effect of 'high dose' (2000 IU/day) vs. 'standard dose' (400 IU/day) vitamin D supplementation in achieving reductions in laboratory confirmed URTI and asthma exacerbations during the winter in preschool-aged Canadian children; and 2) to assess the effect of 'high dose' vitamin D supplementation on vitamin D serum levels and specific viruses that cause URTI.

METHODS/DESIGN

This study is a pragmatic randomized controlled trial. Over 4 successive winters we will recruit 750 healthy children 1-5 years of age. Participating physicians are part of a primary healthcare research network called TARGet Kids!. Children will be randomized to the 'standard dose' or 'high dose' oral supplemental vitamin D for a minimum of 4 months (200 children per group). Parents will obtain a nasal swab from their child with each URTI, report the number of asthma exacerbations and complete symptom checklists. Unscheduled physician visits for URTIs and asthma exacerbations will be recorded. By May, a blood sample will be drawn to determine vitamin D serum levels. The primary analysis will be a comparison of URTI rate between study groups using a Poisson regression model. Secondary analyses will compare vitamin D serum levels, asthma exacerbations and the frequency of specific viral agents between groups.

DISCUSSION

Identifying whether vitamin D supplementation of preschoolers can reduce wintertime viral URTIs and asthma exacerbations and what dose is optimal may reduce population wide morbidity and associated health care and societal costs. This information will assist in determining practice and health policy recommendations related to vitamin D supplementation in healthy Canadian preschoolers.