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

Relationship between vitamin D and asthma from gestational to adulthood period: a meta-analysis of randomized clinical trials

BACKGROUND

Despite numerous studies investigating vitamin D, its impact on asthma is still unknown. The aim of our meta-analysis is to analyze the vitamin D supplementation influence on asthma prevention and treatment ranging from gestational to adulthood period.

METHODS

Fifteen randomized clinical trials were included after database search. Studies contained the analyzed endpoints: the number of asthma and wheezing occurrence in gestational and infantile periods, the change of childhood/adult asthma control test score and forced expiratory volume in one second (FEV1) in childhood and adulthood periods. Random effects model was used to calculate effect sizes.

RESULTS

Supplementation by women during pregnancy period decreased the wheezing occurrence in their children by 23% (RR = 0.77; 95% CI [0.64; 0.92]; p < 0.0049, I² = 0%); whereas had no effect on given asthma parameters during the infantile period. Moreover, vitamin D administration had negative effect on the FEV1 change in children (MD = -3.84; 95% CI [-7.68; -0.01]; p = 0.0497; I² = 95%), but had positive effect on the change of ACT score in adults (MD = 1.80; 95% CI [0.12; 3.49]; p = 0.0359; I² = 99%).

CONCLUSIONS

Our meta-analysis showed the varying results depending on patient's life period. It is important to further investigate the role of vitamin D supplementation in asthma management.

Vitamin D for the management of asthma

BACKGROUND

Since the previous Cochrane Review on this topic in 2016, debate has continued surrounding a potential role for vitamin D in reducing risk of asthma exacerbation and improving asthma control. We therefore conducted an updated meta-analysis to include data from new trials completed since this date.

OBJECTIVES

To evaluate the effectiveness and safety of administration of vitamin D or its hydroxylated metabolites in reducing the risk of severe asthma exacerbations (defined as those requiring treatment with systemic corticosteroids) and improving asthma symptom control.

SEARCH METHODS

We searched the Cochrane Airways Group Trial Register and reference lists of articles. We contacted the authors of studies in order to identify additional trials. Date of last search: 8 September 2022.

SELECTION CRITERIA

We included double-blind, randomised, placebo-controlled trials of vitamin D in children and adults with asthma evaluating exacerbation risk or asthma symptom control, or both.

DATA COLLECTION AND ANALYSIS

Four review authors independently applied study inclusion criteria, extracted the data, and assessed risk of bias. We obtained missing data from the authors where possible. We reported results with 95% confidence intervals (CIs). The primary outcome was the incidence of severe asthma exacerbations requiring treatment with systemic corticosteroids. Secondary outcomes included the incidence of asthma exacerbations precipitating an emergency department visit or requiring hospital admission, or both, end-study childhood Asthma Control Test (cACT) or Asthma Control Test (ACT) scores, and end-study % predicted forced expiratory volume in one second (FEV1). We performed subgroup analyses to determine whether the effect of vitamin D on risk of asthma exacerbation was modified by baseline vitamin D status, vitamin D dose, frequency of dosing regimen, form of vitamin D given, and age of participants.

MAIN RESULTS

We included 20 studies in this review; 15 trials involving a total of 1155 children and five trials involving a total of 1070 adults contributed data to analyses. Participant ages ranged from 1 to 84 years, with two trials providing data specific to participants under five years (n = 69) and eight trials providing data specific to participants aged 5 to 16 (n = 766). Across the trials, 1245 participants were male and 1229 were female, with two studies not reporting sex distribution. Fifteen trials contributed to the primary outcome analysis of exacerbations requiring systemic corticosteroids. The duration of trials ranged from three to 40 months; all but two investigated effects of administering cholecalciferol (vitamin D3). As in the previous Cochrane Review, the majority of participants had mild to moderate asthma, and profound vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25 nmol/L) at baseline was rare. Administration of vitamin D or its hydroxylated metabolites did not reduce or increase the proportion of participants experiencing one or more asthma exacerbations treated with systemic corticosteroids (odds ratio (OR) 1.04, 95% CI 0.81 to 1.34; I2 = 0%; 14 studies, 1778 participants; high-quality evidence). This equates to an absolute risk of 226 per 1000 (95% CI 185 to 273) in the pooled vitamin D group, compared to a baseline risk of 219 participants per 1000 in the pooled placebo group. We also found no effect of vitamin D supplementation on the rate of exacerbations requiring systemic corticosteroids (rate ratio 0.86, 95% CI 0.62 to 1.19; I2 = 60%; 10 studies, 1599 participants; high-quality evidence), or the time to first exacerbation (hazard ratio 0.82, 95% CI 0.59 to 1.15; I2 = 22%; 3 studies, 850 participants; high-quality evidence). Subgroup analysis did not reveal any evidence of effect modification by baseline vitamin D status, vitamin D dose, frequency of dosing regimen, or age. A single trial investigating administration of calcidiol reported a benefit of the intervention for the primary outcome of asthma control. Vitamin D supplementation did not influence any secondary efficacy outcome meta-analysed, which were all based on moderate- or high-quality evidence. We observed no effect on the incidence of serious adverse events (OR 0.89, 95% CI 0.56 to 1.41; I2 = 0%; 12 studies, 1556 participants; high-quality evidence). The effect of vitamin D on fatal asthma exacerbations was not estimable, as no such events occurred in any trial. Six studies reported adverse reactions potentially attributable to vitamin D. These occurred across treatment and control arms and included hypercalciuria, hypervitaminosis D, kidney stones, gastrointestinal symptoms and mild itch. In one trial, we could not ascertain the total number of participants with hypercalciuria from the trial report. We assessed three trials as being at high risk of bias in at least one domain; none of these contributed data to the analysis of the outcomes reported above. Sensitivity analyses that excluded these trials from each outcome to which they contributed did not change the null findings.

AUTHORS' CONCLUSIONS

In contrast to findings of our previous Cochrane Review on this topic, this updated review does not find evidence to support a role for vitamin D supplementation or its hydroxylated metabolites to reduce risk of asthma exacerbations or improve asthma control. Participants with severe asthma and those with baseline 25(OH)D concentrations < 25 nmol/L were poorly represented, so further research is warranted here. A single study investigating effects of calcidiol yielded positive results, so further studies investigating effects of this metabolite are needed.

Calcifediol for Use in Treatment of Respiratory Disease

Calcifediol is the prohormone of the vitamin D endocrine system (VDES). It requires hydroxylation to move to 1,25(OH)2D3 or calcitriol, the active form that exerts its functions by activating the vitamin D receptor (VDR) that is expressed in many organs, including the lungs. Due to its rapid oral absorption and because it does not require first hepatic hydroxylation, it is a good option to replace the prevalent deficiency of vitamin D (25 hydroxyvitamin D; 25OHD), to which patients with respiratory pathologies are no strangers. Correcting 25OHD deficiency can decrease the risk of upper respiratory infections and thus improve asthma and COPD control. The same happens with other respiratory pathologies and, in particular, COVID-19. Calcifediol may be a good option for raising 25OHD serum levels quickly because the profile of inflammatory cytokines exhibited by patients with inflammatory respiratory diseases, such as asthma, COPD or COVID-19, can increase the degradation of the active metabolites of the VDES. The aim of this narrative revision is to report the current evidence on the role of calcifediol in main respiratory diseases. In conclusion, good 25OHD status may have beneficial effects on the clinical course of respiratory diseases, including COVID-19. This hypothesis should be confirmed in large, randomized trials. Otherwise, a rapid correction of 25(OH)D deficiency can be useful for patients with respiratory disease.

Prevention and Management of High-Burden Noncommunicable Diseases in School-Age Children: A Systematic Review

BACKGROUND AND OBJECTIVES

Noncommunicable diseases (NCDs) are chronic conditions requiring health care, education, social and community services, addressing prevention, treatment, and management. This review aimed to summarize and synthesize the available evidence on interventions from systematic reviews of high-burden NCDs and risk factors among school-aged children.

METHODS

The following databases were used for this research: Medline, Embase, The Cochrane Library, and the Campbell library. The search dates were from 2000 to 2021. We included systematic reviews that synthesized studies to evaluate intervention effectiveness in children aged 5 to 19 years globally. Two reviewers independently extracted data and assessed methodological quality of included reviews using the AMSTAR 2 tool.

RESULTS

Fifty studies were included. Asthma had the highest number of eligible reviews (n = 19). Of the reviews reporting the delivery platform, 27% (n = 16) reported outpatient settings, 13% (n = 8) home and community-based respectively, and 8% (n = 5) school-based platforms. Included reviews primarily (69%) reported high-income country data. This may limit the results' generalizability for school-aged children and adolescents in low- and middle- income countries.

CONCLUSIONS

School-aged children and adolescents affected by NCDs require access to quality care, treatment, and support to effectively manage their diseases into adulthood. Strengthening research and the capacity of countries, especially low- and middle- income countries, for early screening, risk education and management of disease are crucial for NCD prevention and control.

Vitamin D supplementation in childhood asthma: a systematic review and meta-analysis of randomised controlled trials

Background

There is conflicting evidence for vitamin D supplementation in childhood asthma. We aimed to systematically synthesise the evidence on the efficacy and safety of vitamin D supplementation in childhood asthma.

Methods

We searched electronic databases (Medline, Embase and Web of Science) and a register (CENTRAL) for randomised controlled trials (RCTs) published until 30 September 2021. RCTs enrolling asthmatic children (1–18 years old) and comparing vitamin D against placebo/routine care were included if they met at least one of the endpoints of interest (asthma attacks, emergency visits or hospitalisation). We used the Risk of Bias 2 tool for risk of bias assessment. Random-effects meta-analysis with RevMan 5.3 software was performed. The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess the level of certainty of the evidence.

Results

18 RCTs (1579 participants) were included. The pooled meta-analysis did not find a significant effect of vitamin D supplementation on asthma attacks requiring rescue systemic corticosteroids (six studies with 445 participants; risk ratio (RR) 1.13, 95% CI 0.86–1.48; I²=0%) (moderate-certainty evidence). In addition, there was no significant difference in the proportion of children with asthma attacks of any severity (11 trials with 1132 participants; RR 0.84, 95% CI 0.65–1.09; I²=58%) (very low-certainty evidence). Vitamin D does not reduce the need for emergency visits (three studies with 361 participants; RR 0.97, 95% CI 0.89–1.07; I²=0%) and hospitalisation (RR: 1.38, 95% CI 0.52–3.66; I²=0%) (low-certainty evidence).

Conclusion

Very low- to moderate-certainty evidence suggests that vitamin D supplementation might not have any protective effect in childhood asthma.

Very low to moderate certainty evidence suggests that adjuvant vitamin D supplementation might not have any protective effect in childhood asthma. Therefore, routine vitamin D supplementation in asthmatic children should be avoided.https://bit.ly/3xQVitV

Impact of rapid correction of vitamin D deficiency in asthmatic patients

BACKGROUND

Asthma is one of the most common chronic diseases, which is a growing public health concern worldwide. In recent years, there has been an increasing number of interests in the relationship between vitamin D level and asthma control. Hence, the objective of this study was to assess the effect of high doses of vitamin D₃ injection on asthmatic patient's respiratory condition and quality of life.

METHODS

This was a single arm, before and after interventional study involving 18 patients with moderate to severe asthma. Spirometry test, St George's respiratory questionnaire (SGRQ) and serum vitamin D assay were performed. Subjects with 25-hydroxyvitamin D₃ (25-(OH) D₃) < 20 ng/ml were deemed deficient (n = 18) and received 2 intramuscular injections of vitamin D₃ 300,000 IU at monthly intervals consecutively.

RESULTS

The mean changes of forced expiratory volume in the first second (FEV1) were significantly different in subjects who received vitamin D₃ injections (p = 0.008). Also, the mean changes in FEV1/forced vital capacity ratio (FEV1/FVC) were significant (p < 0.001) as well as maximum expiratory flow between 25% and 75% of FVC (MEF25-75) (p = 0.001). Interestingly, improvement in clinical parameters of SGRQ was also observed with significant differences in total score (p = 0.001). Naturally, serum vitamin D levels were increased in our patients following the injections (p < 0.001).

CONCLUSIONS

Our findings suggest that screening for serum 25-(OH) D₃ deficiency is important in asthmatic patients and correction of this deficiency with high doses of vitamin D₃ injection may lead to improvement in pulmonary function, symptoms and quality of life (QOL).

Vitamin D and Multiple Health Outcomes: An Umbrella Review of Observational Studies, Randomized Controlled Trials, and Mendelian Randomization Studies

Observational studies, randomized controlled trials (RCTs), and Mendelian randomization (MR) studies have yielded inconsistent results on the associations of vitamin D concentrations with multiple health outcomes. In the present umbrella review we aimed to evaluate the effects of low vitamin D concentrations and vitamin D supplementation on multiple health outcomes. We summarized current evidence obtained from meta-analyses of observational studies that examined associations between vitamin D concentrations and multiple health outcomes, meta-analyses of RCTs that investigated the effect of vitamin D supplementation on multiple health outcomes, and MR studies that explored the causal associations of vitamin D concentrations with various diseases (international prospective register of systematic reviews PROSPERO registration number CRD42018091434). A total of 296 meta-analyses of observational studies comprising 111 unique outcomes, 139 meta-analyses of RCTs comprising 46 unique outcomes, and 73 MR studies comprising 43 unique outcomes were included in the present umbrella review. Twenty-eight disease outcomes were identified by both meta-analyses of observational studies and MR studies. Seventeen of these reported disease outcomes had consistent results, demonstrating that lower concentrations of vitamin D were associated with a higher risk for all-cause mortality, Alzheimer's disease, hypertension, schizophrenia, and type 2 diabetes. The combinations of consistent evidence obtained by meta-analyses of observational studies and MR studies together with meta-analyses of RCTs showed that vitamin D supplementation was associated with a decreased risk for all-cause mortality but not associated with the risk for Alzheimer's disease, hypertension, schizophrenia, or type 2 diabetes. The results indicated that vitamin D supplementation is a promising strategy with long-term preventive effects on multiple chronic diseases and thus has the potential to decrease all-cause mortality. However, the current vitamin D supplementation strategy might not be an efficient intervention approach for these diseases, suggesting that new strategies are highly needed to improve the intervention outcomes.

Effects of oral vitamin D supplementation on linear growth and other health outcomes among children under five years of age

BACKGROUND

Vitamin D is a secosteroid hormone that is important for its role in calcium homeostasis to maintain skeletal health. Linear growth faltering and stunting remain pervasive indicators of poor nutrition status among infants and children under five years of age around the world, and low vitamin D status has been linked to poor growth. However, existing evidence on the effects of vitamin D supplementation on linear growth and other health outcomes among infants and children under five years of age has not been systematically reviewed.

OBJECTIVES

To assess effects of oral vitamin D supplementation on linear growth and other health outcomes among infants and children under five years of age.

SEARCH METHODS

In December 2019, we searched CENTRAL, PubMed, Embase, 14 other electronic databases, and two trials registries. We also searched the reference lists of relevant publications for any relevant trials, and we contacted key organisations and authors to obtain information on relevant ongoing and unpublished trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of oral vitamin D supplementation, with or without other micronutrients, compared to no intervention, placebo, a lower dose of vitamin D, or the same micronutrients alone (and not vitamin D) in infants and children under five years of age who lived in any country.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

Out of 75 studies (187 reports; 12,122 participants) included in the qualitative analysis, 64 studies (169 reports; 10,854 participants) contributed data on our outcomes of interest for meta-analysis. A majority of included studies were conducted in India, USA, and Canada. Two studies reported for-profit funding, two were categorised as receiving mixed funding (non-profit and for-profit), five reported that they received no funding, 26 did not disclose funding sources, and the remaining studies were funded by non-profit funding. Certainty of evidence varied between high and very low across outcomes (all measured at endpoint) for each comparison. Vitamin D supplementation versus placebo or no intervention (31 studies) Compared to placebo or no intervention, vitamin D supplementation (at doses 200 to 2000 IU daily; or up to 300,000 IU bolus at enrolment) may make little to no difference in linear growth (measured length/height in cm) among children under five years of age (mean difference (MD) 0.66, 95% confidence interval (CI) -0.37 to 1.68; 3 studies, 240 participants; low-certainty evidence); probably improves length/height-for-age z-score (L/HAZ) (MD 0.11, 95% CI 0.001 to 0.22; 1 study, 1258 participants; moderate-certainty evidence); and probably makes little to no difference in stunting (risk ratio (RR) 0.90, 95% CI 0.80 to 1.01; 1 study, 1247 participants; moderate-certainty evidence). In terms of adverse events, vitamin D supplementation results in little to no difference in developing hypercalciuria compared to placebo (RR 2.03, 95% CI 0.28 to 14.67; 2 studies, 68 participants; high-certainty evidence). It is uncertain whether vitamin D supplementation impacts the development of hypercalcaemia as the certainty of evidence was very low (RR 0.82, 95% CI 0.35 to 1.90; 2 studies, 367 participants). Vitamin D supplementation (higher dose) versus vitamin D (lower dose) (34 studies) Compared to a lower dose of vitamin D (100 to 1000 IU daily; or up to 300,000 IU bolus at enrolment), higher-dose vitamin D supplementation (200 to 6000 IU daily; or up to 600,000 IU bolus at enrolment) may have little to no effect on linear growth, but we are uncertain about this result (MD 1.00, 95% CI -2.22 to 0.21; 5 studies, 283 participants), and it may make little to no difference in L/HAZ (MD 0.40, 95% CI -0.06 to 0.86; 2 studies, 105 participants; low-certainty evidence). No studies evaluated stunting. As regards adverse events, higher-dose vitamin D supplementation may make little to no difference in developing hypercalciuria (RR 1.16, 95% CI 1.00 to 1.35; 6 studies, 554 participants; low-certainty evidence) or in hypercalcaemia (RR 1.39, 95% CI 0.89 to 2.18; 5 studies, 986 participants; low-certainty evidence) compared to lower-dose vitamin D supplementation. Vitamin D supplementation (higher dose) + micronutrient(s) versus vitamin D (lower dose) + micronutrient(s) (9 studies) Supplementation with a higher dose of vitamin D (400 to 2000 IU daily, or up to 300,000 IU bolus at enrolment) plus micronutrients, compared to a lower dose (200 to 2000 IU daily, or up to 90,000 IU bolus at enrolment) of vitamin D with the same micronutrients, probably makes little to no difference in linear growth (MD 0.60, 95% CI -3.33 to 4.53; 1 study, 25 participants; moderate-certainty evidence). No studies evaluated L/HAZ or stunting. In terms of adverse events, higher-dose vitamin D supplementation with micronutrients, compared to lower-dose vitamin D with the same micronutrients, may make little to no difference in developing hypercalciuria (RR 1.00, 95% CI 0.06 to 15.48; 1 study, 86 participants; low-certainty evidence) and probably makes little to no difference in developing hypercalcaemia (RR 1.00, 95% CI 0.90, 1.11; 2 studies, 126 participants; moderate-certainty evidence). Four studies measured hyperphosphataemia and three studies measured kidney stones, but they reported no occurrences and therefore were not included in the comparison for these outcomes.

AUTHORS' CONCLUSIONS

Evidence suggests that oral vitamin D supplementation may result in little to no difference in linear growth, stunting, hypercalciuria, or hypercalcaemia, compared to placebo or no intervention, but may result in a slight increase in length/height-for-age z-score (L/HAZ). Additionally, evidence suggests that compared to lower doses of vitamin D, with or without micronutrients, vitamin D supplementation may result in little to no difference in linear growth, L/HAZ, stunting, hypercalciuria, or hypercalcaemia. Small sample sizes, substantial heterogeneity in terms of population and intervention parameters, and high risk of bias across many of the included studies limit our ability to confirm with any certainty the effects of vitamin D on our outcomes. Larger, well-designed studies of long duration (several months to years) are recommended to confirm whether or not oral vitamin D supplementation may impact linear growth in children under five years of age, among both those who are healthy and those with underlying infectious or non-communicable health conditions.

Opinions on the current pandemic of COVID-19: Use functional food to boost our immune functions

The pandemic of novel coronavirus caused COVID-19 had resulted in a high number of hospitalizations and deaths and caused a devastating toll on human and society health. The symptoms of the infected patients vary significantly, from life-threatening to mild or even asymptomatic. This clinical observation led to hypothesize on the critical role of host innate immunity in the disease development and progression. As the first defense barrier against microorganisms, the innate immune reaction determines not only the viral infection rate but also immune-mediated response. Therefore, promote healthy behaviors to enhance innate immunity with functional food and nutritional agents may be a rational strategy for minimizing damages caused by viruses to global health.

Prenatal vitamin D supplementation and child respiratory health: A systematic review and meta-analysis of randomized controlled trials

Background

Systematic review and meta-analyses of observational studies on maternal vitamin D status and risk of respiratory allergic conditions indicated that mothers who had supplementation during pregnancy could decrease the risk of recurrent wheeze or asthma in their offspring.

Objectives

We conducted this meta-analysis of Randomized Controlled Trials with the primary intention of detecting the effect of prenatal vitamin D supplementation on the offspring's asthma. Secondary outcomes under respiratory health include eczema, lower respiratory tract infections, Immunoglobulin E positive test, upper respiratory tract infections, and allergic rhinitis.

Methods

A comprehensive search of PubMed, ScienceDirect, Google Scholar, and Cochrane Library databases was performed to retrieve randomized controlled trials. Risk Ratio with 95% confidence intervals was computed from dichotomous data using a random-effects model, with I² >50% representing notable heterogeneity.

Results

Six clinical trials met the inclusion criteria, involving a total of 2898 subjects (1461 experimental group and 1437 control group). There was non-significant inverse relationship between vitamin D intake during pregnancy and the occurrence of asthma in offspring (pooled RR = 0.89, 95% CI = 0.69-1.15, I ²  = 46% and Z-static = 0.90, P-value = 0.37). There is no significant difference in the risk of assessed childhood respiratory problems due to maternal supplementation of vitamin D during pregnancy.

Conclusion and implications

Currently, there is no fertile evidence to promote vitamin D supplementation in pregnancy for childhood respiratory health. Future clinical trials should emphasize early initiation of vitamin D supplementation, consider 6 weeks to 6 months postnatal critical window for vitamin D deficiency for offspring, lower risk dose of vitamin D, and identify different phenotypes of asthma and response to vitamin D supplementation.

Sufficient vitamin D status positively modified ventilatory function in asthmatic children following a Mediterranean diet enriched with fatty fish intervention study

Asthma in children is the most prevalent allergic disease worldwide that has become a major public health priority. The objective of this study was to examine the relationship between baseline serum vitamin D status, spirometry, and fractional exhaled nitric oxide levels (FeNO) in 64 Greek children with 'mild asthma' aged 5 to 12 years (51.6% male) in a dietary intervention study. We hypothesized that baseline serum vitamin D levels modify the beneficial response of fatty fish intake on pulmonary function in asthmatic children following a Mediterranean diet. The intervention group consumed 2 fatty fish meals/week (≥150 g cooked filleted fish/meal) as part of the Mediterranean diet for six months, and the control group consumed their usual diet. Baseline serum 25(OH)D was determined using enzyme-linked immunoassay and defined as sufficient levels of 25(OH)D ≥25 ng/mL. Only 36% of children were graded as sufficient in 25(OH)D levels on entry into the study with a higher proportion of girls insufficient than boys (61% vs 39% respectively). Participants with sufficient levels of serum 25(OH)D at baseline, consuming the intervention diet increased FEV₁/FVC by 4.89 units (β = 4.89; 95%CI: 1.19-8.61; p = 0.013) and FEF_25-75% by 12.83 units (β = 12.83; 95%CI: 4.27-21.40; p = 0.006) compared to controls. No significant differences in pulmonary function or FeNO were observed for those with insufficient levels of 25(OH) D in the intervention or control groups. In conclusion, sufficient serum vitamin D levels enhanced ventilatory function in response to a dietary intervention in asthmatic children.

Role of Vitamin D in Preventing and Treating Selected Extraskeletal Diseases-An Umbrella Review

Evidence is accumulating that vitamin D may have beneficial effects on respiratory tract, autoimmune, neuro-degenerative, and mental diseases. The present umbrella review of systematic reviews (SRs) of cohort studies and randomised controlled trials (RCTs), plus single Mendelian randomisation studies aims to update current knowledge on the potential role of vitamin D in preventing and treating these extraskeletal diseases. Altogether, 73 SRs were identified. Observational data on primary prevention suggest an inverse association between vitamin D status and the risk of acute respiratory tract infections (ARI), dementia and cognitive decline, and depression, whereas studies regarding asthma, multiple sclerosis (MS), and type 1 diabetes mellitus (T1DM) are scarce. SRs of RCTs support observational data only for the risk of ARI. No respective RCTs are available for the prevention of chronic obstructive pulmonary disease (COPD), MS, and T1DM. SRs of RCTs indicate beneficial therapeutic effects in vitamin D-deficient patients with asthma and COPD, while effects on major depression and T1DM need to be further elucidated. Mendelian randomisation studies do not consistently support the results of SRs. Since several limitations of the included SRs and existing RCTs do not permit definitive conclusions regarding vitamin D and the selected diseases, further high-quality RCTs are warranted.

The Immunomodulatory Role of Vitamin D in Respiratory Diseases

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The growing interest in the new role of vitamin D, particularly as an immunomodulatory factor, has spurred basic research and the development of clinical trials to better understand the influence of supplementation on various diseases. Vitamin D is an important nutrient factor in human health due to its role in calcium metabolism regulation, cellular growth, differentiation and its fundamental discovered activity in immune functions. It has influenced different diseases, particularly inflammatory and autoimmune diseases, through immune response regulation, modulating innate and adaptive immunity.

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The aim of this review was to explore the role of vitamin D in the main respiratory diseases in children such as asthma, chronic rhinosinusitis, cystic fibrosis and recurrent respiratory infections.

Implications of vitamin D toxicity & deficiency

Vitamin D deficiency is an increasing problem affecting all ages. Patients should be assessed for risk factors as part of preventive health maintenance. Vitamin D toxicity is a rare occurrence caused by oversupplementation and errors in food fortification. The connection between vitamin D deficiency and osteoporosis, is well established. However, a cause and effect relationship has yet to be established between vitamin D deficiency and many chronic illnesses. An evidence-based approach is treating patients for an underlying vitamin D deficiency in hopes of improving many chronic illnesses.

Meta-analysis of vitamin D and lung function in patients with asthma

Background

There is growing literature suggesting a link between vitamin D and asthma lung function, but the results from systematic reviews are conflicting. We conducted this meta-analysis to investigate the relation between serum vitamin D and lung function in asthma patients.

Methods

Major databases, including OVID, MEDLINE, Web of Science and PUBMED, were searched until 10th October 2018. All published observational studies related to vitamin D and asthma were extracted. All meta-analyses were performed using Review Manager 5.3.5.

Results

This quantitative synthesis found that asthma patients with low vitamin D levels had lower forced expiratory volume In 1 s (FEV1) (mean difference (MD) = − 0.1, 95% CI = − 0.11 to − 0.08,p < 0.01;I2 = 49%, p = 0.12) and FEV1% (MD = − 10.02, 95% CI = − 11 to − 9.04, p < 0.01; I2 = 0%, p = 0.82) than those with sufficient vitamin D levels. A positive relation was found between vitamin D and FEV1 (r = 0.12, 95% CI = 0.04 to 0.2, p = 0.003; I2 = 59%,p = 0.01), FEV1% (r = 0.19, 95% CI = 0.13 to 0.26, p < 0.001; I2 = 42%, p = 0.11), forced vital capacity (FVC) (r = 0.17, 95% CI = 0.00 to 0.34, p = 0.05; I2 = 60%, p = 0.04), FEV1/FVC (r = 0.4, 95% CI = 0.3 to 0.51, p < 0.001; I2 = 48%, p = 0.07), and the asthma control test (ACT) (r = 0.33, 95% CI = 0.2 to 0.47, p < 0.001; I2 = 0%, p = 0.7). Subgroup analysis indicated that the positive correlation between vitamin D and lung function remained significant in both children and adults.

Conclusions

Our meta-analysis suggested that serum vitamin D levels may be positively correlated with lung function in asthma patients. Future comprehensive studies are required to confirm these relations and to elucidate potential mechanisms.

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.

Association between vitamin D status and asthma control: A meta-analysis of randomized trials

BACKGROUND

There is a controversy in terms of the efficacy of vitamin D supplementation in improving asthma symptom control. Moreover, whether there is a difference in the treatment effect with respect to baseline vitamin D status remains unknown. This meta-analysis was to assess the correlations of vitamin D status with asthma-related respiratory outcomes.

METHODS

PubMed, EMBASE, and Cochrane Library were searched for randomized controlled trials of vitamin D supplementation in patients with asthma. Primary outcomes were the rate of asthma exacerbation and predicted percentage of forced expiratory volume in first second (FEV₁%). Secondary outcomes were asthma control test (ACT) scores, fractional exhaled nitric oxide (FeNO), interleukin-10 (IL-10) and adverse events.

RESULTS

A total of 14 randomized controlled trials (1421 participants) fulfilled the inclusion. Vitamin D supplementation was associated with a significant reduction in the rate of asthma exacerbation by 27% (RR: 0.73 95%Cl (0.58-0.92)). In subgroup analysis, the protective effect of exacerbation was restricted in patients with vitamin D insufficiency (vitamin D < 30 ng/ml) (RR: 0.76 95%Cl (0.61-0.95)). An improvement of FEV₁% was demonstrated in patients with vitamin D insufficiency and air limitation (FEV₁% < 80%) (MD: 8.3 95%Cl (5.95-10.64). No significant difference was observed in ACT scores, FeNO, IL-10 and adverse events.

CONCLUSIONS

Vitamin D supplementation reduced the rate of asthma exacerbation, especially in patients with vitamin D insufficiency. Additionally, the benefit of vitamin D had a positive effect on pulmonary function in patients with air limitation and vitamin D insufficiency.

Vitamin D intake, serum 25-hydroxy vitamin D and pulmonary function in paediatric patients with cystic fibrosis: a longitudinal approach

Pancreatic-insufficient children with cystic fibrosis (CF) receive age-group-specific vitamin D supplementation according to international CF nutritional guidelines. The potential advantageous immunomodulatory effect of serum 25-hydroxy vitamin D (25(OH)D) on pulmonary function (PF) is yet to be established and is complicated by CF-related vitamin D malabsorption. We aimed to assess whether current recommendations are optimal for preventing deficiencies and whether higher serum 25(OH)D levels have long-term beneficial effects on PF. We examined the longitudinal relationship between vitamin D intake, serum 25(OH)D and PF in 190 CF children during a 4-year follow-up period. We found a significant relationship between total vitamin D intake and serum 25(OH)D (β = 0·02; 95 % CI 0·01, 0·03; P = 0·000). However, serum 25(OH)D decreased with increasing body weight (β = –0·79; 95 % CI –1·28, –0·29; P = 0·002). Furthermore, we observed a significant relationship between serum 25(OH)D and forced expiratory volume in 1 s (β = 0·056; 95 % CI 0·01, 0·102; P = 0·018) and forced vital capacity (β = 0·045; 95 % CI 0·008, 0·082; P = 0·017). In the present large study sample, vitamin D intake is associated with serum 25(OH)D levels, and adequate serum 25(OH)D levels may contribute to the preservation of PF in children with CF. Furthermore, to maintain adequate levels of serum 25(OH)D, vitamin D supplementation should increase with increasing body weight. Adjustments of the international CF nutritional guidelines, in which vitamin D supplementation increases with increasing weight, should be considered.

Children with Obesity and Asthma: Which Are the Best Options for Their Management?

Obesity and asthma are complex disorders related to gene-environment interactions and various lifestyle factors. At present, they represent two of the most significant paediatric health problems worldwide, particularly in industrialized nations. The aim of this narrative review is to evaluate possible therapeutic strategies to manage asthma in children with overweight/obesity. PubMed was used to search for all of the studies published from January 2008 to June 2018 using the following key words: “asthma” and “overweight” or “obesity” or “obese” and “children” or “paediatric”. The literature review showed that growing evidence underlines the existence of an “obese asthma” phenotype characterised by difficult-to-control asthma with additional symptoms, worse control, more frequent and severe exacerbations, reduced response to inhaled corticosteroids, and lower quality of life than other phenotypes. Currently, therapeutic strategies centred on prevention are suggested and the development of resources to assist families with weight loss strategies seems useful for effective weight control and optimal asthma management. Studies on vitamin D supplementation and further knowledge are needed to better define the best therapeutic options to manage asthma in children with overweight/obesity and to reduce the onset and severity of this chronic respiratory disease through the design of a multifactorial intervention.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

Does Vitamin D Deficiency Affect the Immunogenic Responses to Influenza Vaccination? A Systematic Review and Meta-Analysis

Influenza virus infection is a major global public health problem, and the efficacy of influenza vaccination is not satisfactory. Vitamin D is involved in many immune-mediated inflammatory processes. The impact of vitamin D levels on the immunogenic response to influenza vaccination is not clear. We performed a comprehensive literature search and systematic review of studies that investigated vitamin D and influenza vaccination. Data pertaining to study population, vaccine components, vitamin D levels, and immunogenic response were analyzed. Nine studies, with a combined study population of 2367 patients, were included in the systematic review. Four studies were included in the meta-analysis to investigate the influence of vitamin D deficiency (VDD) on the seroprotection (SP) rates and seroconversion (SC) rates following influenza vaccination. We found no significant association between vitamin D level and the immunogenic response to influenza vaccination. However, strain-specific differences may exist. We observed lower SP rates of influenza A virus subtype H3N2 (A/H3N2) and B strain in VDD patients than patients with normal vitamin D levels (A/H3N2: 71.8% vs. 80.1%, odds ratio (OR): 0.63, 95% confidence interval (CI): 0.43-0.91, p = 0.01; B strain: 69.6% vs. 76.4%, OR: 0.68, 95% CI: 0.5-0.93, p = 0.01). However, the SP rates of A/H1N1 and SC rates of all three strains were not significantly different in VDD and control groups. In conclusion, no association was observed between VDD and immunogenic response to influenza vaccination.

Evaluation of serum 25-hidroxy vitamin D and zinc levels in asthmatic patients

Introduction:

We aimed to investigate the impact of serum zinc, and vitamin D levels on the development of asthma, and its clinical characteristics.

Methods:

In our cross-sectional study; 50 patients who were diagnosed as atopic asthma and 70 healthy children consisted the control group. In both groups levels of vitamin D, and zinc were analyzed.

Results:

A statistically significant intergroup difference was not detected as for age, gender, body height (percentile), and weight (percentile) of the patients (p>0.05). Mean vitamin D levels in the asthmatic patient, and control groups were 32.61±9.48 nmol/L, and 42.55±15.42 nmol/L, respectively. Between two groups a statistically significant difference was found (p=0.001). Zinc levels were higher in the control group without any statistically significant difference between groups (p=0.25). A statistically significant negative correlation (−0.635) was found between vitamin D levels, and severity of asthma in the patient group. As the level of vitamin D increased, a decrease in severity of asthma was seen (p=0.04).

Conclusion:

Though larger series are needed to arrive at definitive conclusions, we think that vitamin D deficiency rather than zinc deficiency, might convey importance in the emergence, and exacerbation of asthma.

The potential of anti-infectives and immunomodulators as therapies for asthma and asthma exacerbations

Asthma is responsible for approximately 25,000 deaths annually in Europe despite available medicines that maintain asthma control and reduce asthma exacerbations. Better treatments are urgently needed for the control of chronic asthma and reduction in asthma exacerbations, the major cause of asthma mortality. Much research spanning >20 years shows a strong association between microorganisms including pathogens in asthma onset, severity and exacerbation, yet with the exception of antibiotics, few treatments are available that specifically target the offending pathogens. Recent insights into the microbiome suggest that modulating commensal organisms within the gut or lung may also be a possible way to treat/prevent asthma. The European Academy of Allergy & Clinical Immunology Task Force on Anti-infectives in Asthma was initiated to investigate the potential of anti-infectives and immunomodulators in asthma. This review provides a concise summary of the current literature and aimed to identify and address key questions that concern the use of anti-infectives and both microbe- and host-based immunomodulators and their feasibility for use in asthma.

Vitamin D deficiency in critically ill children: a systematic review and meta-analysis

BACKGROUND

Vitamin D deficiency (VDD) has been hypothesized not only to be common but also to represent a potentially modifiable risk factor for greater illness severity and clinical outcome during critical illness. The objective of this systematic review was to determine the frequency of VDD in pediatric critical illness and its association with clinical outcomes.

METHODS

MEDLINE, Embase, and CENTRAL were searched through December 12, 2016, with no date or language restrictions. The primary objective was to estimate the prevalence of VDD in the pediatric intensive care unit (PICU) and compare vitamin D status with healthy control populations. Secondary objectives were to evaluate whether VDD is associated with mortality, increased illness severity, PICU interventions, and patient clinical course. Random effects meta-analysis was used to calculate pooled VDD event rate, compare levels with those of control subjects, and evaluate for associations between VDD and clinical outcome.

RESULTS

Among 2700 citations, 17 studies meeting study eligibility were identified. The studies reported a total of 2783 critically ill children and had a median sample size of 120 (range 12-511). The majority of studies used a 25-hydroxyvitamin D [25(OH)D] level less than 50 nmol/L to define VDD, and the pooled VDD prevalence was 54.8 (95% CI 45.4-63.9). Average 25(OH)D levels were significantly lower in PICU patients than in healthy control subjects (pooled difference -17.3 nmol/L, 95% CI -14.0 to -20.6). In a meta-analysis calculation, we found that VDD was associated with increased mortality (OR 1.62, 95% CI 1.11-2.36), illness severity, and need for PICU interventions.

CONCLUSIONS

Approximately 50% of critically ill children have VDD at the time of PICU admission, defined as a blood total 25(OH)D concentration under 50 nmol/L. VDD was further determined to be associated with greater illness severity, multiple organ dysfunction, and mortality in the PICU setting. Clinical trials are required to determine if optimization of vitamin D status improves patient outcome.

TRIAL REGISTRATION

PROSPERO, CRD42016026617 . Registered on 11 January 2016.

Vitamin D metabolic loci and vitamin D status in Black and White pregnant women

BACKGROUND

Several candidate genes and genome wide association studies have reported significant associations between vitamin D metabolism genes and 25-hydroxyvitamin D. Few studies have examined these relationships in pregnancy.

OBJECTIVE

We evaluated the relationship between maternal allelic variants in three vitamin D metabolism genes and 25-hydroxyvitamin D (25(OH)D) concentration in pregnancy.

STUDY DESIGN

In two case-control studies, samples were drawn from women who delivered at Magee Womens Hospital in Pittsburgh, PA from 1999 to 2010 and twelve recruiting sites across the United States from 1959 to 65. For 882 Black and 1796 White pregnant women from these studies, 25(OH)D concentration was measured and single nucleotide polymorphisms (SNPs) were genotyped 50 kilobases up- and down-stream in three genes (VDR, GC, and CYP27B1). Using multivariable linear regression, we estimated the associations between allelic variation of each locus and log-transformed 25(OH)D concentration separately by race and study group. Meta-analysis was used to estimate the association across the four groups for each SNP.

RESULTS

Minor alleles of several variants in VDR, GC, and CYP27B1 were associated with differences in log-transformed 25(OH)D concentration compared to the corresponding major alleles [beta, 95% confidence intervals (CI)]. The meta-analysis confirmed the associations for differences in log-transformed 25(OH)D by allelic loci for one intron VDR variant [rs2853559 0.08 (0.02, 0.13), p<0.01] and a variant in the GC flanking region [rs13150174: 0.04 (0.02, 0.07), p<0.01], and a GC missense mutation [rs7041 0.05 (0.01, 0.09), p<0.01]. The meta-analysis also revealed possible associations for SNPs in linkage disequilibrium with variants in the VDR 3-prime untranslated region, another GC missense variant (rs4588), and a variant of the 3-prime untranslated region of CYP27B1.

CONCLUSION

We observed associations between VDR, GC, and CYP27B1 variants and maternal 25-hydroxyvitamin D concentration. Our results provide additional support for a possible role of genetic variation in vitamin D metabolism genes on vitamin D status during pregnancy.

Vitamin D supplementation to prevent asthma exacerbations: a systematic review and meta-analysis of individual participant data

BACKGROUND

A previous aggregate data meta-analysis of randomised controlled trials showed that vitamin D supplementation reduces the rate of asthma exacerbations requiring treatment with systemic corticosteroids. Whether this effect is restricted to patients with low baseline vitamin D status is unknown.

METHODS

For this systematic review and one-step and two-step meta-analysis of individual participant data, we searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science for double-blind, placebo-controlled, randomised controlled trials of vitamin D₃ or vitamin D₂ supplementation in people with asthma that reported incidence of asthma exacerbation, published between database inception and Oct 26, 2016. We analysed individual participant data requested from the principal investigator for each eligible trial, adjusting for age and sex, and clustering by study. The primary outcome was the incidence of asthma exacerbation requiring treatment with systemic corticosteroids. Mixed-effects regression models were used to obtain the pooled intervention effect with a 95% CI. Subgroup analyses were done to determine whether effects of vitamin D on risk of asthma exacerbation varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration, age, ethnic or racial origin, body-mass index, vitamin D dosing regimen, use of inhaled corticosteroids, or end-study 25(OH)D levels; post-hoc subgroup analyses were done according to sex and study duration. This study was registered with PROSPERO, number CRD42014013953.

FINDINGS

Our search identified 483 unique studies, eight of which were eligible randomised controlled trials (total 1078 participants). We sought individual participant data for each and obtained it for seven studies (955 participants). Vitamin D supplementation reduced the rate of asthma exacerbation requiring treatment with systemic corticosteroids among all participants (adjusted incidence rate ratio [aIRR] 0·74, 95% CI 0·56-0·97; p=0·03; 955 participants in seven studies; high-quality evidence). There were no significant differences between vitamin D and placebo in the proportion of participants with at least one exacerbation or time to first exacerbation. Subgroup analyses of the rate of asthma exacerbations treated with systemic corticosteroids revealed that protective effects were seen in participants with baseline 25(OH)D of less than 25 nmol/L (aIRR 0·33, 0·11-0·98; p=0·046; 92 participants in three studies; moderate-quality evidence) but not in participants with higher baseline 25(OH)D levels (aIRR 0·77, 0·58-1·03; p=0·08; 764 participants in six studies; moderate-quality evidence; p_interaction=0·25). p values for interaction for all other subgroup analyses were also higher than 0·05; therefore, we did not show that the effects of this intervention are stronger in any one subgroup than in another. Six studies were assessed as being at low risk of bias, and one was assessed as being at unclear risk of bias. The two-step meta-analysis did not reveal evidence of heterogeneity of effect (I²=0·0, p=0·56).

INTERPRETATION

Vitamin D supplementation reduced the rate of asthma exacerbations requiring treatment with systemic corticosteroids overall. We did not find definitive evidence that effects of this intervention differed across subgroups of patients.

FUNDING

Health Technology Assessment Program, National Institute for Health Research (reference number 13/03/25).

How much is too much? Two contrasting cases of excessive vitamin D supplementation

BACKGROUND

In this report, we describe 2 contrasting cases of hypervitaminosis D.

CASE PRESENTATION

Patient 1 was a 75-y old man who developed symptomatic hypercalcemia (peak serum calcium concentration of 15.3mg/dl; reference range: 8.5-10.6mg/dl), cardiac injury, and a high total serum vitamin D concentration of 243ng/ml (30-80ng/ml) as a result of daily consumption of prescribed 50,000IU ergocalciferol (vitamin D2) and 500mg calcium-citrate for 1y. Patient 2 was a 60-y old woman who consumed 40,000IU of cholecalciferol (vitamin D3) daily for >10months with a peak total serum vitamin D concentration of 479ng/ml (30-80ng/ml), but did not present with symptoms related to vitamin D toxicity.

CONCLUSION

These cases demonstrate that individual responses to supraphysiologic concentrations of vitamin D for extended periods of time vary widely, and that defining a toxic concentration of this vitamin is difficult. The different outcomes in these two patients, despite months of high-dose vitamin D therapy, demonstrates that individual patient pharmacodynamics determine clinical sequelae.

Rapid vs Maintenance Vitamin D Supplementation in Deficient Children With Asthma to Prevent Exacerbations

BACKGROUND

Whether vitamin D reduces clinically important exacerbations of childhood asthma remains uncertain. We compared rapid to maintenance vitamin D repletion analyzed by baseline vitamin D level.

METHODS

Children presenting to the ED with moderate-to-severe asthma exacerbations and vitamin D levels ≤ 25 ng/mL underwent masked randomization, and then open dosing to either IM+oral (the latter daily) therapy or daily oral-only therapy, and were followed for 12 months. The primary outcome was patient-initiated unplanned visits for asthma exacerbations, examined two ways: cumulative proportions with an exacerbation, and average exacerbation frequency. As this was a nutrient study, we analyzed treatment groups by quartile of baseline vitamin D level, collecting repeat levels and clinical observations at 3, 6, 9, and 12 months after enrollment.

RESULTS

One hundred and sixteen patients in the IM+oral cohort vs 115 in the oral-only cohort had similar mean (SD) baseline levels: 15.1 (5.4) vs 15.8 (5.2) ng/mL (range, 3-25 ng/mL). There was no difference in the primary outcome over the entire 12-month observation period. However, rapid IM+oral supplementation significantly reduced unplanned visits for asthma exacerbations for children with baseline levels of 3 to 11 ng/mL during the initial 3 months: the relative exacerbation rate for the IM+oral cohort compared with the oral-only cohort at 3 months was 0.48 (95% CI, 0.28-0.89; P = .008); average exacerbation frequency per child analysis, relative rate 0.36 (95% CI, 0.13-0.87; P = .017). Otherwise, there were no significant differences between groups.

CONCLUSIONS

Rapid compared to maintenance vitamin D supplementation for children with the lowest levels resulted in short- but not long-term reduction in asthma exacerbations.

Vitamin D regulates immunoglobulin mucin domain molecule-4 expression in dendritic cells

BACKGROUND

Dendritic cell (DC)-derived immunoglobulin domain molecule (TIM)4 plays a critical role in the initiation of T helper (Th)2 polarization. Vitamin D (VitD) involves the regulation of a number of immune responses.

OBJECTIVES

This study tests a hypothesis that VitD regulates TIM4 expression in DCs.

METHODS

Peripheral blood samples were collected from patients with allergic rhinitis (AR) and healthy subjects. DCs were isolated from the samples and analyzed for the expression of TIM4.

RESULTS

We observed that the levels of calcitriol, the active form of VitD3, in the sera of AR patients were lower than that in healthy subjects. The peripheral DC expressed higher levels of TIM4 and lower levels of VDR. A negative correlation was identified between the data of serum calcitriol and TIM4 in DCs. Exposure DCs to calcitriol in the culture increased the expression of VDR. We also found that VDR bound to the TIM4 promoter locus in DCs to repress the TIM4 gene transcription and expression.

CONCLUSIONS AND CLINICAL RELEVANCE

VitD deficiency may contribute to the pathogenesis of AR by increasing the TIM4 expression. The results suggest that to regulate the serum calcitriol levels and the expression of VDR in DCs may be necessary to be taken into account in the treatment of AR.

Vitamin D levels in children affected by vernal keratoconjunctivitis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a chronic and often severe bilateral conjunctivitis. VKC etiology still remains unclear although endocrine, genetic, neurogenic and environmental factors have been implicated. Vitamin D is a fat-soluble prohormone whose main function is the regulation of calcium and phosphate metabolism. The aim of this study was to evaluate serum vitamin D in children affected by VKC compared to the healthy children and investigate the relationship between its levels and disease severity.

METHODS

A total of 110 children, 47 affected by VKC, aged between 5 and 12 years were enrolled at the Department of Pediatrics, Division of Allergy and Immunology, "Sapienza" University of Rome. Used as controls were 63 healthy children with negative skin prick test (SPT), without allergic, ocular and systemic disease. Serum samples were obtained in April from all the children included in the study. Vitamin D dosage was repeated in October in 20 patients after therapy and in 20 controls. A conjunctival scraping was performed in all children affected by VKC.

RESULTS

Children affected by VKC had lower vitamin D levels compared to healthy controls and we found an increase in vitamin D levels after therapy with cyclosporine eye drops 1% although this increase was lower than that of healthy controls. Moreover we found significant correlations between vitamin D level and the severity of the disease.

CONCLUSIONS

The study shows that children affected by VKC have lower vitamin D levels when compared to healthy controls and highlights a significant correlation between its levels and disease severity.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Adequate Vitamin D Intake but Low Serum Levels in Pediatric Asthma Patients: A Pilot Study, Alberta Children's Hospital

Background. We assessed vitamin D intakes and serum 25(OH) vitamin D levels in pediatric asthma patients on moderate-to-high dose inhaled steroids and compared them to published findings of healthy children in our city. Methods. Parents and/or patients were interviewed to estimate the children's vitamin D intakes from foods and supplements (using an adapted validated food frequency questionnaire) and asthma duration and management. Vitamin D status: serum 25-hyroxy vitamin D (25(OH)D) was obtained from the medical records. Results. Vitamin D intakes from food and supplements of the asthma patients (n = 20, 742 ± 185 IU/day) were significantly higher compared to healthy Canadian children (n = 1442, 229 ± 121 IU/day). Despite higher vitamin D intakes, the children had nonsignificantly lower serum 25(OH) vitamin D levels compared to the comparison group. Serum 25(OH)D levels increased by 3.6 nmol/L with each 100 IU of vitamin D intake (95% Confidence interval = 2.0-4.0, R² = 0.931, and p = 0.001). Conclusion. Since adequate vitamin D status in asthma patients is necessary to support bone mineral accretion, it is important to achieve adequate vitamin D status by checking serum 25(OH)D status and supplement accordingly.

Vitamin D supplementation during pregnancy and infancy reduces aeroallergen sensitization: a randomized controlled trial

BACKGROUND

Vitamin D has immune-modulating effects. We determined whether vitamin D supplementation during pregnancy and infancy prevents aeroallergen sensitization and primary care respiratory illness presentations.

METHODS

A randomized, double-blind, placebo-controlled parallel-group trial. We assigned pregnant women, from 27-week gestation to birth, and then their infants, from birth to 6 months, to placebo or one of two dosages of daily oral vitamin D. Woman/infant pairs were randomized to: placebo/placebo, 1000 IU/400 IU or 2000 IU/800 IU. When the children were 18 months old, we measured serum-specific IgE antibodies and identified acute primary care visits described by the doctor to be due to a cold, otitis media, an upper respiratory infection, croup, asthma, bronchitis, bronchiolitis, a wheezy lower respiratory infection or fever and cough.

RESULTS

Specific IgE was measured on 185 of 260 (71%) enrolled children. The proportion of children sensitized differed by study group for four mite antigens: Dermatophagoides farinae (Der-f1, Der-f2) and Dermatophagoides pteronyssinus (Der-p1, Der-p2). With results presented for placebo, lower dose, and higher dose vitamin D, respectively (all P < 0.05): Der-f1 (18%, 10%, 2%), Der-f2 (14%, 3%, 2%), Der-p1 (19%, 14%, 3%) and Der-p2 (12%, 2%, 3%). There were study group differences in the proportion of children with primary care visits described by the doctor as being for asthma (11%, 0%, 4%, P = 0.002), but not for the other respiratory diagnoses.

CONCLUSIONS

Vitamin D supplementation during pregnancy and infancy reduces the proportion of children sensitized to mites at age 18 months. Preliminary data indicate a possible effect on primary care visits where asthma is diagnosed.

Identification of genes differentially regulated by vitamin D deficiency that alter lung pathophysiology and inflammation in allergic airways disease

Vitamin D deficiency is associated with asthma risk. Vitamin D deficiency may enhance the inflammatory response, and we have previously shown that airway remodeling and airway hyperresponsiveness is increased in vitamin D-deficient mice. In this study, we hypothesize that vitamin D deficiency would exacerbate house dust mite (HDM)-induced inflammation and alterations in lung structure and function. A BALB/c mouse model of vitamin D deficiency was established by dietary manipulation. Responsiveness to methacholine, airway smooth muscle (ASM) mass, mucus cell metaplasia, lung and airway inflammation, and cytokines in bronchoalveolar lavage (BAL) fluid were assessed. Gene expression patterns in mouse lung samples were profiled by RNA-Seq. HDM exposure increased inflammation and inflammatory cytokines in BAL, baseline airway resistance, tissue elastance, and ASM mass. Vitamin D deficiency enhanced the HDM-induced influx of lymphocytes into BAL, ameliorated the HDM-induced increase in ASM mass, and protected against the HDM-induced increase in baseline airway resistance. RNA-Seq identified nine genes that were differentially regulated by vitamin D deficiency in the lungs of HDM-treated mice. Immunohistochemical staining confirmed that protein expression of midline 1 (MID1) and adrenomedullin was differentially regulated such that they promoted inflammation, while hypoxia-inducible lipid droplet-associated, which is associated with ASM remodeling, was downregulated. Protein expression studies in human bronchial epithelial cells also showed that addition of vitamin D decreased MID1 expression. Differential regulation of these genes by vitamin D deficiency could determine lung inflammation and pathophysiology and suggest that the effect of vitamin D deficiency on HDM-induced allergic airways disease is complex.

Vitamin D Deficiency in Pediatric Critical Care

Vitamin D deficiency (VDD) is a well-established cause of pediatric bone and muscle disease. In addition, a role has been recognized for vitamin D in the health and stress response of other organs, including the cardiovascular, immune, and respiratory systems. As these organs are central to the development of and recovery from critical illness, VDD has been hypothesized to be a modifiable risk factor for ICU outcome. Over the past 5 years, a growing number of adult and pediatric critical care studies have investigated the prevalence of VDD and its association with illness severity and outcome. The adult studies have recently been synthesized in systematic reviews, with results that convincingly suggest the need for trials to determine whether optimization of vitamin D status improves outcome. In contrast, the pediatric ICU and related literature has not been similarly synthesized. The goal of this review is to describe vitamin D metabolism, known biological mechanisms, potential role in pathophysiology, and summarize the available pediatric intensive care unit (PICU) studies reporting on prevalence of VDD deficiency and its association with outcome. The problems with currently approved supplementation approaches and alternative strategies are discussed, including evidence from available RCTs in adult ICU. Altogether the results suggest that critically ill children are at risk for VDD, and that VDD appears to be associated with a worse clinical course. Clinical trials evaluating novel approaches to testing for and supplementing vitamin D require exploration.

A systematic review of pediatric clinical trials of high dose vitamin D

Background. Due to inadequate UV exposure, intake of small quantities of vitamin D is recommended to prevent musculoskeletal disease. Both basic science and observational literature strongly suggest that higher doses may benefit specific populations and have non-musculoskeletal roles. Evaluating the evidence surrounding high dose supplementation can be challenging given a relatively large and growing body of clinical trial evidence spanning time, geography, populations and dosing regimens. Study objectives were to identify and summarize the clinical trial literature, recognize areas with high quality evidence, and develop a resource database that makes the literature more immediately accessible to end users. Methods. Medline (1946 to January 2015), Embase (1974 to January 2015), and Cochrane databases (January 2015), were searched for trials. All pediatric (0-18 years) trials administering doses higher than 400 IU (<1 year) or 600 IU (≥1 year) were included. Data was extracted independently by two of the authors. An online searchable database of trials was developed containing relevant extracted information (http://www.cheori.org/en/pedvitaminddatabaseOverview). Sensitivity and utility were assessed by comparing the trials in the database with those from systematic reviews of vitamin D supplementation including children. Results. A total of 2,579 candidate papers were identified, yielding 169 trials having one or more arms meeting eligibility criteria. The publication rate has increased significantly from 1 per year (1970-1979) to 14 per year (2010-2015). Although 84% of the total trials focused on healthy children or known high risk populations (e.g., renal, prematurity), this proportion has declined in recent years due to the rise in trials evaluating populations and outcomes not directly related to the musculoskeletal actions of vitamin D (27% in 2010s). Beyond healthy children, the only pediatric populations with more than 50 participants from low risk of bias trials evaluating a clinically relevant outcome were prematurity and respiratory illness. Finally, we created and validated the online searchable database using 13 recent systematic reviews. Of the 38 high dose trials identified by the systematic review, 36 (94.7%) could be found within the database. When compared with the search strategy reported in each systematic review, use of the database reduced the number of full papers to assess for eligibility by 85.2% (±13.4%). Conclusion. The pediatric vitamin D field is highly active, with a significant increase in trials evaluating non-classical diseases and outcomes. Despite the large overall number there are few high quality trials of sufficient size to provide answers on clinical efficacy of high-dose vitamin D. An open access online searchable data should assist end users in the rapid and comprehensive identification and evaluation of trials relevant to their population or question of interest.

Update on the current methods for the diagnosis and treatment of severe childhood asthma

The level of asthma control is the key outcome towards which asthma management is evaluated. The majority of children with asthma can obtain adequate control of symptoms through avoidance of triggering factors and/or with the help of low to moderate doses of current available medications. However, there is still a group of children with poor symptom control despite intensive treatment. The current review will provide an overview of a standardized approach to characterize this heterogeneous group of severely sick children. Factors that attenuate the effect of the prescribed treatment and make asthma difficult to treat are discussed. In addition, the usefulness of current methods of assessing asthma severity, pulmonary function, allergy and airway inflammation is also described. Finally, an overview of therapeutic options for children with severe asthma is provided.

Vitamin D Supplementation for Childhood Asthma: A Systematic Review and Meta-Analysis

Importance

There is growing evidence that vitamin D plays a role in the pathogenesis of asthma but it is unclear whether supplementation during childhood may improve asthma outcomes.

Objectives

The objective of this systematic review and meta-analysis was to evaluate the efficacy and safety of vitamin D supplementation as a treatment or adjunct treatment for asthma.

Data Sources

We searched MEDLINE, Embase, CENTRAL, and CINAHL through July 2014.

Study Selection

We included RCTs that evaluated vitamin D supplementation in children versus active control or placebo for asthma.

Data Extraction and Synthesis

One reviewer extracted data and one reviewer verified data accuracy. We qualitatively summarized the main results of efficacy and safety and meta-analyzed data on comparable outcomes across studies. We used GRADE for strength of evidence.

Main Outcome Measures

Main planned outcomes measures were ED visits and hospitalizations. As secondary outcomes, we examined measures of asthma control, including frequency of asthma exacerbations, asthma symptom scores, measures of lung function, β₂-agonist use and daily steroid use, adverse events and 25-hydroxyvitamin D levels.

Results

Eight RCTs (one parallel, one crossover design) comprising 573 children aged 3 to 18 years were included. One study (moderate-quality, n = 100) reported significantly less ED visits for children treated with vitamin D. No other studies examined the primary outcome (ED visits and hospitalizations). There was a reduced risk of asthma exacerbations in children receiving vitamin D (low-quality; RR 0.41, 95% CI 0.27 to 0.63, 3 studies, n = 378). There was no significant effect for asthma symptom scores and lung function. The serum 25(OH)D level was higher in the vitamin D group at the end of the intervention (low-quality; MD 19.66 nmol/L, 95% CI 5.96 nmol/L to 33.37 nmol/L, 5 studies, n = 167).

Limitations

We identified a high degree of clinical diversity (interventions and outcomes) and methodological heterogeneity (sample size and risk of bias) in included trials.

Conclusions and Relevance

Randomized controlled trials provide some low-quality evidence to support vitamin D supplementation for the reduction of asthma exacerbations. Evidence on the benefits of vitamin D supplementation for other asthma-related outcomes in children is either limited or inconclusive. We recommend that future trials focus on patient-relevant outcomes that are comparable across studies, including standardized definitions of asthma exacerbations.

Emphasizing the health benefits of vitamin D for those with neurodevelopmental disorders and intellectual disabilities

People with neurodevelopmental disorders and intellectual disabilities have much greater health care needs. Mainly staying indoors, such people generally have low 25-hydroxyvitamin D (25(OH)D) concentrations. The Vitamin D Task Force of the American Academy of Developmental Medicine and Dentistry (AADMD) reviewed the evidence of 25(OH)D concentrations that benefit the health of persons with developmental disabilities. Maintaining recommended optimal serum 25(OH)D concentrations year long will benefit skeletal development in infants, children, and adolescents, and benefit musculoskeletal health and neuromuscular coordination in adult patients, and decrease risk of falls. Maintaining optimal concentrations decreases risks and severities of autoimmune diseases, cardiovascular disease, many types of cancer, dementia, types 1 and 2 diabetes mellitus, and respiratory tract infections. Other benefits include improved dental and oral health and improved physical performance. The Task Force recommends that 25(OH)D concentrations for optimal health to be in the range of 75 to 125 nmol/L, which can be achieved using between 800 and 4000 IU/day vitamin D3 and sensible exposure to solar UVB radiation. The paper also discusses the potential risks of higher 25(OH)D concentrations, the evidence from and limitations of randomized controlled trials, and the recommendations by various groups and agencies.