Vitamin D supplementation for the prevention of childhood acute respiratory infections: a systematic review of randomised controlled trials. Br J Nutr. 2015;114:1026-1034. [PMID: 26310436 DOI: 10.1017/s000711451500207x]

Vitamin D supplementation for prevention of acute respiratory infections in older adults: A systematic review and meta-analysis

BACKGROUND

Acute respiratory infections (ARIs) have a substantial impact on morbidity, healthcare utilization, and functional decline among older adults. Therefore, we systematically reviewed evidence from randomized controlled trials (RCTs) to evaluate the efficacy and safety of vitamin D supplementation in preventing ARIs in older adults.

METHODS

PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov were searched until 1 February 2024. RCTs evaluating the use of vitamin D supplements to protect older adults from ARIs were included. Two reviewers independently screened papers, extracted the data and assessed the risk of bias. Data were summarised as relative risks (RRs) or odds ratios (ORs) with corresponding 95% confidence intervals (CIs). Random effects meta-analyses were used to synthesise the results. GRADE was used to evaluate the quality of evidence. All the analysis were performed with Stata version 17.

RESULTS

Twelve trials (41552 participants) were included in the meta-analysis. It showed that vitamin D supplementation probably does not reduce the incidence of ARIs (RR, 0.99; 95% CI, 0.97-1.02, I2 = 0%; moderate certainty). No significant effect of vitamin D supplementation on the risk of ARI was observed for any of the subgroups defined by baseline 25(OH)D concentration, control treatments, dose frequency, study duration, and participants' condition. However, there was a possibility, although not statistically significant, that vitamin D may reduce the risk of ARI in patients with a baseline 25(OH)D concentration <50 nmol/L (OR, 0.90; 95% CI, 0.79-1.04, I2 = 14.7%). Additionally, vitamin D supplements might result in little to no difference in death due to any cause, any adverse event, hypercalcinemia, and kidney stones.

CONCLUSIONS

Vitamin D supplementation among older adults probably results in little to no difference in the incidence of ARIs. However, further evidence is needed, particularly for individuals with vitamin D deficiency and populations residing in low and middle income countries.

TRIAL REGISTRATION

This study was registered on PROSPERO (CRD42023451265).

Analysis of risk factors for the formation of insufficiency and deficiency of vitamin D in children

The article discusses the main risk factors for the formation of insufficiency and deficiency of vitamin D in children. Particular attention is paid to the course and dietary preferences of the mother during pregnancy, the intake of vitamin and mineral complexes, the nutrition of the child after birth, the type of feeding, the subsidy of vitamin D preparations and complementary foods. 1246 children under four years of age with no history of vitamin D deficiency were examined. With clinical manifestations of rickets, 52 children were identified, who underwent determination of 25(OH) D in serum, while low availability was detected in 21.1%, vitamin D insufficiency — in 63.4% of children, deficiency — in 15.3% of cases. There was an interaction between the use of dairy products enriched with a vitamin-mineral complex containing vitamin D and Ca, the use of therapeutic doses of vitamin D, and an increase in the level of 25 (OH) D in the blood serum.

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.

Exclusive Breastfeeding and Vitamin D Supplementation: A Positive Synergistic Effect on Prevention of Childhood Infections?

Human milk is the best food for infants. Breastfeeding has been associated with a reduced risk of viral and bacterial infections. Breast milk contains the perfect amount of nutrients needed to promote infant growth, except for vitamin D. Vitamin D is crucial for calcium metabolism and bone health, and it also has extra-skeletal actions, involving innate and adaptive immunity. As exclusive breastfeeding is a risk factor for vitamin D deficiency, infants should be supplemented with vitamin D at least during the first year. The promotion of breastfeeding and vitamin D supplementation represents an important objective of public health.

Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials

Background: Previous systematic reviews and meta-analyses of randomized controlled trials (RCTs) have reported inconsistent results regarding the efficacy of vitamin D supplements in the prevention of acute respiratory infections (ARIs). Methods: We investigated these efficacy results by using a meta-analysis of RCTs. We searched PubMed, EMBASE, and the Cochrane Library in June 2021. Results: Out of 390 trials searched from the database, a total of 30 RCTs involving 30,263 participants were included in the final analysis. In the meta-analysis of all the trials, vitamin D supplementation showed no significant effect in the prevention of ARIs (relative risk (RR) 0.96, 95% confidence interval (CI) 0.91–1.01, I² = 59.0%, n = 30). In the subgroup meta-analysis, vitamin D supplementation was effective in daily supplementation (RR 0.83, 95% CI, 0.73–0.95, I² = 69.1%, n = 15) and short-term supplementation (RR 0.83, 95% CI, 0.71–0.97, I² = 66.8%, n = 13). However, such beneficial effects disappeared in the subgroup meta-analysis of high-quality studies (RR 0.89, 95% CI, 0.78–1.02, I² = 67.0%, n = 10 assessed by the Jadad scale; RR 0.87, 95% CI, 0.66–1.15, I² = 51.0%, n = 4 assessed by the Cochrane’s risk of bias tool). Additionally, publication bias was observed. Conclusions: The current meta-analysis found that vitamin D supplementation has no clinical effect in the prevention of ARIs.

Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials

Background: Vitamin D supplementation improves the immune function of human body and can be a convenient way to prevent influenza. However, evidence on the protective effect of vitamin D supplementation on influenza from Randomized Controlled Trials (RCTs) is inconclusive.

Methods: RCTs regarding the association between vitamin D supplementation and influenza were identified by searching PubMed, Cochrane library, Embase and Chinese Biomedical Database (CBM) from inception until present (last updated on 10 November 2021). Studies that reported dosages and durations of vitamin D supplementation and number of influenza infections could be included. Heterogeneity was assessed using Cochran's Q test and I² statistics, the meta-analysis was conducted by using a random-effects model, the pooled effects were expressed with risk ratio (RR) with 95% confidence interval (95% CI).

Results: 10 trials including 4859 individuals were ultimately eligible after scanning. There was no evidence of a significant heterogeneity among studies (I² = 27%, P = 0.150). Meta-regression analysis finding indicated that country, latitude, average age, economic level, follow-up period and average daily vitamin D intake did not cause the statistical heterogeneity. The study finding indicates that substitution with vitamin D significantly reduces the risk of influenza infections (RR = 0.78, 95% CI:0.64–0.95). No evidence of publication bias was observed. Omission of any single trial had little impact on the pooled risk estimates.

Conclusions: The meta-analysis produced a corroboration that vitamin D supplement has a preventive effect on influenza. Strategies for preventing influenza can be optimized by vitamin D supplementation.

Efficacy and safety of vitamin D supplementation in hospitalized COVID-19 pediatric patients: A randomized controlled trial

BACKGROUND

Some studies suggested that adequate levels of vitamin D (VD) decrease the risk of severe COVID-19. Information about the effectiveness of VD supplementation in children is scarce.

OBJECTIVE

To assess the efficacy and safety of VD supplementation compared to the standard of care in hospitalized children with COVID-19.

PATIENTS AND METHODS

An open-label randomized controlled single-blind clinical trial was carried out. We included patients from 1 month to 17 years, with moderate COVID-19, who required hospitalization and supplemental oxygen. They were randomized into two groups: the VD group, which received doses of 1,000 (children < 1 year) or 2,000 IU/day (from 1 to 17 years) and the group without VD (control). The outcome variables were the progression of oxygen requirement, the development of complications, and death.

STATISTICAL ANALYSIS

For comparison between groups, we used the chi-squared test or Fisher's exact test and the Mann-Whitney U test. Absolute risk reduction (ARR) and the number needed to treat (NNT) were calculated. p ≤ 0.05 was considered statistically significant.

RESULTS

From 24 March 2020 to 31 March 2021, 87 patients were eligible to participate in the trial; 45 patients were randomized: 20 to the VD group and 25 to the control group. There was no difference in general characteristics at baseline, including serum VD levels (median 13.8 ng/ml in the VD group and 11.4 ng/ml in the control group).

OUTCOMES

2/20 (10%) in the VD group vs. 9/25 (36%) in the control group progressed to a superior ventilation modality (p = 0.10); one patient in the VD group died (5%) compared to 6 (24%) patients in the control group (p = 0.23). ARR was 26% (95% CI 8.8 to 60.2%) and NNT was 3 (2 to 11) for progression and ARR was 19% (95% CI -3.9 to 42.8%) and NNT was 6 (2 to 26) for death. None of the patients receiving VD had adverse effects. The trial was stopped for ethical reasons; since after receiving the results of the basal VD values, none of the patients had normal levels.

CONCLUSION

In this trial, VD supplementation in pediatric patients seems to decrease the risk of COVID-19 progression and death. More studies are needed to confirm these findings.

CLINICAL TRIAL REGISTRATION

This protocol was registered on ClinicalTrials.gov with the registration number NCT04502667.

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.

Prevention of recurrent respiratory infections : Inter-society Consensus

Recurrent respiratory infections (RRIs) are a common clinical condition in children, in fact about 25% of children under 1 year and 6% of children during the first 6 years of life have RRIs. In most cases, infections occur with mild clinical manifestations and the frequency of episodes tends to decrease over time with a complete resolution by 12 years of age. However, RRIs significantly reduce child and family quality of life and lead to significant medical and social costs.Despite the importance of this condition, there is currently no agreed definition of the term RRIs in the literature, especially concerning the frequency and type of infectious episodes to be considered. The aim of this consensus document is to propose an updated definition and provide recommendations with the intent of guiding the physician in the complex process of diagnosis, management and prevention of RRIs.

Vitamin D supplementation, COVID-19 and disease severity: a meta-analysis

OBJECTIVE

Current meta-analysis aims to understand the effect of oral supplementation of vitamin D on intensive care unit (ICU) requirement and mortality in hospitalized COVID-19 patients.

METHODS

Databases PubMed, preprint servers, and google scholar were searched from December 2019 to December 2020. Authors searched for the articles assessing role of vitamin D supplementation on COVID-19. Cochrane RevMan tool was used for quantitative assessment of the data, where heterogeneity was assessed using I2 and Q statistics and data was expressed using odds ratio with 95% confidence interval.

RESULTS

Final meta-analysis involved pooled data of 532 hospitalized patients (189 on vitamin D supplementation and 343 on usual care/placebo) of COVID-19 from three studies (Two randomized controlled trials, one retrospective case-control study). Statistically (p<0.0001) lower ICU requirement was observed in patients with vitamin D supplementation as compared to patients without supplementations (odds ratio: 0.36; 95% CI: 0.210-0.626). However, it suffered from significant heterogeneity, which reduced after sensitivity analysis. In case of mortality, vitamin D supplements has comparable findings with placebo treatment/usual care (odds ratio: 0.93; 95% CI: 0.413-2.113; p=0.87). The studies did not show any publication bias and had fair quality score. Subgroup analysis could not be performed due to limited number of studies and hence dose and duration dependent effect of vitamin D could not be evaluated.

CONCLUSIONS

Although the current meta-analysis findings indicate potential role of vitamin D in improving COVID-19 severity in hospitalized patients, more robust data from randomized controlled trials are needed to substantiate its effects on mortality.

Lack of association of baseline 25-hydroxyvitamin D levels with disease severity and mortality in Indian patients hospitalized for COVID-19

Vitamin D deficiency (VDD) owing to its immunomodulatory effects is believed to influence outcomes in COVID-19. We conducted a prospective, observational study of patients, hospitalized with COVID-19. Serum 25-OHD level < 20 ng/mL was considered VDD. Patients were classified as having mild and severe disease on basis of the WHO ordinal scale for clinical improvement (OSCI). Of the 410 patients recruited, patients with VDD (197,48.2%) were significantly younger and had lesser comorbidities. The levels of PTH were significantly higher in the VDD group (63.5 ± 54.4 vs. 47.5 ± 42.9 pg/mL). The proportion of severe cases (13.2% vs.14.6%), mortality (2% vs. 5.2%), oxygen requirement (34.5% vs.43.4%), ICU admission (14.7% vs.19.8%) was not significantly different between patients with or without VDD. There was no significant correlation between serum 25-OHD levels and inflammatory markers studied. Serum parathormone levels correlated with D-dimer (r 0.117, p- 0.019), ferritin (r 0.132, p-0.010), and LDH (r 0.124, p-0.018). Amongst VDD patients, 128(64.9%) were treated with oral cholecalciferol (median dose of 60,000 IU). The proportion of severe cases, oxygen, or ICU admission was not significantly different in the treated vs. untreated group. In conclusion, serum 25-OHD levels at admission did not correlate with inflammatory markers, clinical outcomes, or mortality in hospitalized COVID-19 patients. Treatment of VDD with cholecalciferol did not make any difference to the outcomes.

Contribution of comorbidities to obesity-related asthma in children

Children with obesity are at increased risk for developing asthma that is difficult to control. A complicating factor to asthma management among these children is likely the commonplace co-morbidities that also result from obesity. We discuss three common obesity-related comorbidities which appear to complicate the effective management of asthma, including hypovitaminosis D, obstructive sleep apnea and gastro-esophageal reflux. Each conditions requires more research to understand their effects on asthma management.

Role of Vitamin D in Risk Reduction of COVID-19: A Narrative Review

The world is in the midst of the COVID-19 pandemic. In addition to quarantine, public health interventions which can reduce the risk of infection and death are urgently required. This article discusses the roles of vitamin D in reducing the risk of COVID-19, and how vitamin D supplementation may be a useful risk reduction measure. Vitamin D can reduce the risk of infections through a variety of mechanisms: induction of cathelicidins and defensins that can lower the rate of viral replication and decrease the concentrations of pro-inflammatory cytokines, which are responsible for induction of inflammation, injuring lining of lungs and contributing to developing pneumonia. Evidence supporting the role of vitamin D in reducing the incidence of COVID-19 includes a) winter outbreak; b) a timeframe when concentrations of 25-hydroxyvitamin D (25(OH)D) are lowest; c) a small number of cases in the southern hemisphere toward the end of summer; d) a vitamin D deficiency found to lead to acute respiratory distress syndrome (ARDS); e) and a rise in case-fatality rates with increasing age and comorbid chronic diseases, both of which are associated with lower concentrations of 25(OH)D. It is recommended that people at risk of COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly increase 25(OH)D concentrations, followed by 5,000 IU/d to reduce the risk of infection. Higher doses of vitamin D3 may be useful for treating people who are infected with COVID-19. To test these guidelines, randomized controlled trials and comprehensive population studies should be performed.

The effect of vitamin D supplementation on acute respiratory tract infection in older Australian adults: an analysis of data from the D-Health Trial

BACKGROUND

Observational studies have linked vitamin D deficiency with acute respiratory tract infection, but results from randomised controlled trials are heterogeneous. We analysed data from the D-Health Trial to determine whether supplementing older Australian adults, recruited from the general population, with monthly doses of vitamin D reduced the risk, duration, and severity of acute respiratory tract infections.

METHODS

We used data from the D-Health Trial, a randomised, double-blind, placebo-controlled trial of monthly vitamin D supplementation, for which acute respiratory infection was a pre-specified trial outcome. Participants were supplemented and followed for up to 5 years. The trial was set within the Australian general population, using the Commonwealth Electoral Roll as the sampling frame, but also allowing some volunteers to participate. Participants were men and women aged 60 to 79 years (with volunteers up to age 84 years). Participants were randomly assigned to receive either vitamin D or placebo (1:1) using computer-generated permuted block randomisation, which was stratified by age, sex, and state. This was an automated process and the assignment list was not visible to study staff or investigators. Active and placebo gel capsules, identical in appearance to ensure masking, were labelled A and B and the code was not available to study staff or investigators. Participants were asked to report occurrence of acute respiratory symptoms over the previous month via annual surveys, and a subset of participants completed 8-week respiratory symptom diaries in winter. As part of our process to maintain blinding, a random sample of participants was selected for analysis of survey data and a separate sample selected for analysis of diary data. Blood samples were obtained from a random sample of participants (about 450 per group per year) and serum 25-hydroxy vitamin D (25[OH]D) concentrations were measured to monitor adherence. We used regression models to estimate odds ratios (OR), rate ratios, and rate differences. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12613000743763.

FINDINGS

Between Jan 13, 2014, and May 26, 2015, 421 207 invitations were sent, 40 824 people were interested in participating, and 21 315 participants were recruited and randomised. Of the 16 000 participants selected for potential analysis of survey data, 15 373 were included in the analysis; 295 in the vitamin D group and 332 in the placebo group who were missing data for all five annual surveys were excluded from the analysis. Of the 3800 selected for potential analysis of diary data, 3070 were invited to complete the diaries because 730 had already withdrawn. 2598 people were included in the analysis; 218 people in the vitamin D group and 254 in the placebo group were missing data and were therefore excluded from the analysis. In blood samples collected from randomly sampled participants throughout the trial, the mean serum 25(OH)D concentration was 114·8 (SD 30·3) nmol/L in the vitamin D group and 77·5 (25·2) nmol/L in the placebo group. Vitamin D supplementation did not reduce the risk of acute respiratory tract infection (survey OR 0·98, 95% CI 0·93 to 1·02; diary OR 0·98, 0·83 to 1·15). Analyses of diary data showed reductions in the overall duration of symptoms and of severe symptoms, but these were small and unlikely to be clinically significant.

INTERPRETATION

Monthly bolus doses of 60 000 IU of vitamin D did not reduce the overall risk of acute respiratory tract infection, but could slightly reduce the duration of symptoms in the general population. These findings suggest that routine vitamin D supplementation of a population that is largely vitamin D replete is unlikely to have a clinically relevant effect on acute respiratory tract infection.

FUNDING

National Health and Medical Research Council.

Differences in RAAS/vitamin D linked to genetics and socioeconomic factors could explain the higher mortality rate in African Americans with COVID-19

COVID-19 is said to be a pandemic that does not distinguish between skin color or ethnic origin. However, data in many parts of the world, especially in the United States, begin to show that there is a sector of society suffering a more significant impact from this pandemic. The Black population is more vulnerable than the White population to infection and death by COVID-19, with hypertension and diabetes mellitus as probable predisposing factors. Over time, multiple disparities have been observed between the health of Black and White populations, associated mainly with socioeconomic inequalities. However, some mechanisms and pathophysiological susceptibilities begin to be elucidated that are related directly to the higher prevalence of multiple diseases in the Black population, including infection and death by COVID-19. Plasma vitamin D levels and evolutionary adaptations of the renin-angiotensin-aldosterone system (RAAS) in Black people differ considerably from those of other races. The role of these factors in the development and progression of hypertension and multiple lung diseases, among them SARS-CoV-2 infection, is well established. In this sense, the present review attempts to elucidate the link between vitamin D and RAAS ethnic disparities and susceptibility to infection and death by COVID-19 in Black people, and suggests possible mechanisms for this susceptibility.

Intake of 25-Hydroxyvitamin D3 May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study

To evaluate the effects of 25-hydroxyvitamin D₃ (25OHD) on symptoms at the onset of the upper respiratory tract infection (URTI) in subjects with insufficient or deficient serum 25-hydroxyvitamin D levels, we conducted a post hoc analysis of data from a randomized, placebo-controlled study; the subjects received 10 μg of 25OHD per day or a placebo for 16 weeks. The Wisconsin Upper Respiratory Symptom Survey-21 was used to determine URTI. The study endpoints included WURSS-21 scores, number of URTI events, and proportion of medication (antibiotics, antipyretic analgesics) usage. We found that the physical symptom scores for "Runny nose," "Sneezing," and "Head congestion" were significantly lower in the 25OHD group than in the placebo group; for all items except "Breathe easily, "the quality of life" scores were significantly improved in the 25OHD group. There was no significant difference in the number of URTI events or the proportion of medication use between the groups. Collectively, the findings of this study indicate that a sufficient 25OHD intake can reduce physical symptoms at the onset of upper respiratory tract infection, particularly nasal symptoms, and may improve the quality of life at the time of onset.

The effects of vitamin D on acute viral respiratory infections: A rapid review

BRIEF OVERVIEW

Current evidence suggests vitamin D replacement may reduce risk for acute respiratory tract infections (ARTI) in people with deficiency or insufficiency, although the effects of supplementation on incidence and severity of ARTI in the general population remain unknown. Oral vitamin D supplemzentation taken at routine doses appears to be generally safe and well tolerated.

VERDICT

Current experimental evidence remains inconclusive regarding the effects of vitamin D supplementation in the general population for the prevention and treatment of acute respiratory tract infections (ARTI). There is also insufficient evidence to draw conclusions regarding the impact of vitamin D supplementation on the severity or duration of ARTI, nor on outcomes related to lung injury or hospitalization from ARTI. Based on this rapid review, sources of significant heterogeneity in published clinical trials include: differences study populations, inconsistent assessment of serum status at baseline, dosing variability, varying routes of administration, and/or inconsistent definitions of outcome measures. Experimental evidence and observations in large cohorts are generally consistent that vitamin D deficiency (<50 nmol/L [<20 ng/mL]) and insufficiency (<75 nmol/L [<30 ng/mL]) of serum 25-hydroxycholecalciferol (25-OHD) concentration is associated with increased risk of ARTI, and supplementation for those with deficiency/insufficiency may lead to clinically meaningful reductions in the incidence of ARTI. In this rapid review, vitamin D was primarily administered as oral supplementation, and findings suggested significant differences in daily oral dosing compared to periodic bolus dosing. Based on the available experimental evidence, vitamin D supplementation appears to have a high margin of safety with very few adverse events reported in children or adults from a variety of dosing strategies. Future clinical trials on vitamin D should consider the sources of heterogeneity in the existing experimental research and design trials that account for baseline status, evaluate the potential for prevention and treatment in at risk populations, standardize dosing strategies, assess product quality, assess outcomes according to gold standard definitions/diagnostic methods, and delineate viral ARTI from other causes when possible. The available mechanistic evidence related to immunological requirements for adequate vitamin D, the availability of observational and experimental evidence suggestive of clinically meaningful benefits (especially in deficient/insufficient participants), and the high margin of safety, should make vitamin D a high priority for additional clinical research during the current COVID-19 pandemic.

Association Between Vitamin D and Novel SARS-CoV-2 Respiratory Dysfunction - A Scoping Review of Current Evidence and Its Implication for COVID-19 Pandemic

OBJECTIVES

To assess the association between vitamin D deficiency and increased morbidity/mortality with COVID-19 respiratory dysfunction.

DESIGN

Scoping review.

DATA SOURCES

Ovid MEDLINE (1946 to 24 of April 2020) and PubMed (2020 to 17 of September 2020).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

A search using the search terms: [(cholecalciferol or ergocalciferol or vitamin D2 or vitamin D3 or vitamin D or 25OHD) and (SARS-CoV-2 or coronavirus or COVID or betacoronavirus or MERS-CoV or SARS-CoV or respiratory infection or acute respiratory distress syndrome or ARDS)]m.p. was conducted on the 24/04/2020 (Search A) and 17/09/2020 (Search B).

RESULTS

91 studies were identified as being concerned with Acute Respiratory Infection (ARI)/Acute Respiratory Distress Syndrome (ARDS) and vitamin D, and 25 publications specifically explored the role of vitamin D deficiency in the development and progression of SARS-CoV-2/COVID-19 related ARDS. Search "A" identified three main themes of indirect evidence supporting such an association. Consistent epidemiological evidence exists linking low vitamin D levels to increased risk and severity of respiratory tract infections. We also report on plausible biological processes supporting such an association; and present weaker evidence supporting the benefit of vitamin D supplementation in reducing the risk and severity of ARIs. Uncertainty remains about what constitutes an appropriate dosing regimen in relation to reducing risk/severity of ARI/ARDS. More recent evidence (Search B) provided new insights into some direct links between vitamin D and COVID-19; with a number of cohort and ecological studies supporting an association with PCR-positivity for SARS-CoV-2 and vitamin D deficiency. The exact efficacy of the vitamin D supplementation for prevention of, or as an adjunct treatment for COVID-19 remains to be determined; but a number of randomized control trials (RCTs) currently underway are actively investigating these potential benefits.

CONCLUSION

Our rapid review of literature supports the need for observational studies with COVID-19 infected populations to measure and assess vitamin D levels in relation to risk/severity and outcomes; alongside RCTs designed to evaluate the efficacy of supplementation both in preventive and therapeutic contexts. The overlap in the vitamin D associated biological pathways with the dysregulation reported to drive COVID-19 outcomes warrants further investigation.

Prevention of New Respiratory Episodes in Children with Recurrent Respiratory Infections: An Expert Consensus Statement

In healthy infants and young children, the development of respiratory tract infections (RTIs) is extremely common. In this paper, we present an international consensus of the available approaches for the prevention of recurrent RTIs in children, including the atopic/allergic ones as well as those with asthma. Few convincing measures for reducing the frequency and clinical relevance of recurrent respiratory episodes in RTI-prone children have been developed until now. Among the most recently suggested measures, immunotherapy is attractive, but only for OM-85 is there a sufficient number of well-conducted clinical trials confirming efficacy in RTIs prevention with an adequate safety profile. In the case of probiotics, it is not clear which bacteria can offer the best results and which dosage and schedule of administration are the most effective. The problems of dosage and the schedule of administration are not solved also for vitamin D, despite some promising efficacy results. While we wait for new knowledge, the elimination or reduction as much as possible of the environmental factors that favor RTIs, vaccination when available and/or indicated, and the systematic application of the traditional methods for infection prevention, such as hand washing, remain the best measures to prevent recurrent infections in RTI-prone children.

Current status of COVID-19 pandemic; characteristics, diagnosis, prevention, and treatment

Humans have always been encountered to big infectious diseases outbreak throughout the history. In December 2019, novel coronavirus (COVID-19) was first noticed as an agent causing insidious pneumonia in Wuhan, China. COVID-19 was spread rapidly from Wuhan to the rest of the world. Until late June 2020, it infected more than 10,000,000 people and caused more than 500,000 deaths in almost all of countries in the world, creating a global crisis worse than all previous epidemics and pandemics. In the current review, we gathered and summarized the results of various studies on characteristics, diagnosis, treatment, and prevention of this pandemic crisis.

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection

Although we lack enough evidence to justify supplementing with vitamin D in the prevention and treatment of COVID-19 infection, it is increasingly feasible that this hypothesis is valid. Two general underlying mechanisms should be considered. One would be the anti-infectious and immunomodulatory action that it exerts by improving intercellular barriers by stimulating innate immunity, as well as by modulating adaptive immunity. Also, vitamin D reduces the production of inflammatory cytokines, such as IL-2 and interferon-gamma (INFγ). More recently, multiple pleiotropic effects have been demonstrated on the actions of vitamin D at the anti-inflammatory and immunomodulatory level with positive results in studies with influenza, coronavirus, and other respiratory infections. An inverse relationship between serum vitamin D levels and the prevalence of the respiratory infectious disease has been described. Of interest, another mechanistic approach responds to considering the inhibition of the renin-angiotensin-aldosterone system (RAAS), which is exacerbated in COVID-19 infection because the virus binds to the enzyme ACE2, making more angiotensin II available to cause damage. Vitamin D inhibits mediators of RAAS – present in all cells of the body – and by inhibiting ACE activity and increasing ACE2, it lowers angiotensin II levels. We present studies with proposals for recommended doses of vitamin D, and although a single guideline is not specified, the possible benefits are promising. Finally, the purpose of this review is to share this idea with health professionals to ignite the debate and call for critical reflection, so that it can contribute to the undertaking of more and better clinical designs to validate the benefits of using high doses of vitamin D for the benefit of public health and especially in times of crisis for COVID-19.

Are Adequate Vitamin D Levels Helpful in Fighting COVID-19? A Look at the Evidence

COVID-19 is a global pandemic with high mortality in vulnerable groups. Given the current lack of definitive treatment or vaccine that significantly reduces mortality rate, governments, researchers and healthcare providers are racing to find possible solutions to the crisis. Vitamin D and its analogues have been previously studied for their non-skeletal benefits. In particular, questions regarding their role in the modulation of immunity have re-surfaced, in view of possible epidemiological links observed between COVID-19 and vitamin D levels in selected populations. In this review, we highlight potential mechanisms and summarise the evidence for and against the potential role of vitamin D supplementation in our fight against COVID-19.

Enhancing innate immunity against virus in times of COVID-19: Trying to untangle facts from fictions

Introduction

In light of the current COVID-19 pandemic, during which the world is confronted with a new, highly contagious virus that suppresses innate immunity as one of its initial virulence mechanisms, thus escaping from first-line human defense mechanisms, enhancing innate immunity seems a good preventive strategy.

Methods

Without the intention to write an official systematic review, but more to give an overview of possible strategies, in this review article we discuss several interventions that might stimulate innate immunity and thus our defense against (viral) respiratory tract infections. Some of these interventions can also stimulate the adaptive T- and B-cell responses, but our main focus is on the innate part of immunity. We divide the reviewed interventions into: 1) lifestyle related (exercise, >7 h sleep, forest walking, meditation/mindfulness, vitamin supplementation); 2) Non-specific immune stimulants (letting fever advance, bacterial vaccines, probiotics, dialyzable leukocyte extract, pidotimod), and 3) specific vaccines with heterologous effect (BCG vaccine, mumps-measles-rubeola vaccine, etc).

Results

For each of these interventions we briefly comment on their definition, possible mechanisms and evidence of clinical efficacy or lack of it, especially focusing on respiratory tract infections, viral infections, and eventually a reduced mortality in severe respiratory infections in the intensive care unit. At the end, a summary table demonstrates the best trials supporting (or not) clinical evidence.

Conclusion

Several interventions have some degree of evidence for enhancing the innate immune response and thus conveying possible benefit, but specific trials in COVID-19 should be conducted to support solid recommendations.

Vitamin D high doses supplementation could represent a promising alternative to prevent or treat COVID-19 infection

Si bien carecemos de suficiente evidencia que justifique suplementar con vitamina D en la prevención y/o tratamiento de la infección por COVID-19, a la fecha resulta cada vez más factible que esta hipótesis sea válida. Dos mecanismos básicos generales deberían ser considerados. Uno sería la acción antiinfecciosa e inmunomoduladora que ejerce mejorando las barreras intercelulares por estímulo de la inmunidad innata, así también por modulación de la inmunidad adaptativa. También, la vitamina D reduce la producción de citoquinas inflamatorias como IL-2 e interferón gamma (INF-γ). Más recientemente se han demostrado múltiples efectos pleiotrópicos sobre las acciones de la vitamina D a nivel antiinflamatorio e inmunomodulador. Esto explica resultados positivos en estudios con influenza, coronavirus y otras infecciones respiratorias. Se ha descrito relación inversa entre niveles séricos de vitamina D y prevalencia de patología infecciosa respiratoria. De interés, otro abordaje mecanístico responde a considerar la inhibición del sistema renina-angiotensina-aldosterona, que se exacerba en la infección por COVID-19 debido a que el virus se une a la enzima ECA2, quedando disponible más angiotensina II para causar daño. La vitamina D inhibe mediadores del SRAA —presente en todas las células del organismo—, y al inhibir la actividad ECA y aumentar la ECA2, disminuye los niveles de angiotensina II. Presentamos estudios con propuestas de dosis recomendadas de vitamina D, y aunque no quede concretada una única guía, los posibles beneficios son promisorios. Finalmente, el propósito de la presente revisión es compartir esta idea con profesionales de la salud para encender el debate y llamar a la reflexión crítica, de modo tal que se pueda contribuir con el emprendimiento de diseños clínicos adecuados para validar los beneficios de utilizar altas dosis de vitamina D en beneficio de la salud pública, sobre todo en tiempos de esta emergencia por COVID-19.

Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis

BACKGROUND

Randomised controlled trials (RCTs) exploring the potential of vitamin D to prevent acute respiratory infections have yielded mixed results. Individual participant data (IPD) meta-analysis has the potential to identify factors that may explain this heterogeneity.

OBJECTIVES

To assess the overall effect of vitamin D supplementation on the risk of acute respiratory infections (ARIs) and to identify factors modifying this effect.

DATA SOURCES

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, ClinicalTrials.gov and the International Standard Randomised Controlled Trials Number (ISRCTN) registry.

STUDY SELECTION

Randomised, double-blind, placebo-controlled trials of supplementation with vitamin D₃ or vitamin D₂ of any duration having incidence of acute respiratory infection as a prespecified efficacy outcome were selected.

STUDY APPRAISAL

Study quality was assessed using the Cochrane Collaboration Risk of Bias tool to assess sequence generation, allocation concealment, blinding of participants, personnel and outcome assessors, completeness of outcome data, evidence of selective outcome reporting and other potential threats to validity.

RESULTS

We identified 25 eligible RCTs (a total of 11,321 participants, aged from 0 to 95 years). IPD were obtained for 10,933 out of 11,321 (96.6%) participants. Vitamin D supplementation reduced the risk of ARI among all participants [adjusted odds ratio (aOR) 0.88, 95% confidence interval (CI) 0.81 to 0.96; heterogeneity p < 0.001]. Subgroup analysis revealed that protective effects were seen in individuals receiving daily or weekly vitamin D without additional bolus doses (aOR 0.81, 95% CI 0.72 to 0.91), but not in those receiving one or more bolus doses (aOR 0.97, 95% CI 0.86 to 1.10; p = 0.05). Among those receiving daily or weekly vitamin D, protective effects of vitamin D were stronger in individuals with a baseline 25-hydroxyvitamin D [25(OH)D] concentration of < 25 nmol/l (aOR 0.30, 95% CI 0.17 to 0.53) than in those with a baseline 25(OH)D concentration of ≥ 25 nmol/l (aOR 0.75, 95% CI 0.60 to 0.95; p = 0.006). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (aOR 0.98, 95% CI 0.80 to 1.20; p = 0.83). The body of evidence contributing to these analyses was assessed as being of high quality.

LIMITATIONS

Our study had limited power to detect the effects of vitamin D supplementation on the risk of upper versus lower respiratory infection, analysed separately.

CONCLUSIONS

Vitamin D supplementation was safe, and it protected against ARIs overall. Very deficient individuals and those not receiving bolus doses experienced the benefit. Incorporation of additional IPD from ongoing trials in the field has the potential to increase statistical power for analyses of secondary outcomes.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013953.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

A Review of Micronutrients and the Immune System-Working in Harmony to Reduce the Risk of Infection

Immune support by micronutrients is historically based on vitamin C deficiency and supplementation in scurvy in early times. It has since been established that the complex, integrated immune system needs multiple specific micronutrients, including vitamins A, D, C, E, B6, and B12, folate, zinc, iron, copper, and selenium, which play vital, often synergistic roles at every stage of the immune response. Adequate amounts are essential to ensure the proper function of physical barriers and immune cells; however, daily micronutrient intakes necessary to support immune function may be higher than current recommended dietary allowances. Certain populations have inadequate dietary micronutrient intakes, and situations with increased requirements (e.g., infection, stress, and pollution) further decrease stores within the body. Several micronutrients may be deficient, and even marginal deficiency may impair immunity. Although contradictory data exist, available evidence indicates that supplementation with multiple micronutrients with immune-supporting roles may modulate immune function and reduce the risk of infection. Micronutrients with the strongest evidence for immune support are vitamins C and D and zinc. Better design of human clinical studies addressing dosage and combinations of micronutrients in different populations are required to substantiate the benefits of micronutrient supplementation against infection.

Vitamin D in the prevention of exacerbations of asthma in preschoolers (DIVA): protocol for a multicentre randomised placebo-controlled triple-blind trial

INTRODUCTION

Preschoolers have the highest rate of emergency visits and hospitalisations for asthma exacerbations of all age groups, with most triggered by upper respiratory tract infections (URTIs) and occurring in the fall or winter. Vitamin D insufficiency is highly prevalent in Canadian preschoolers with recurrent asthma exacerbations, particularly in winter. It is associated with more URTIs and, in patients with asthma, more oral corticosteroid (OCS) use. Although evidence suggests that vitamin D supplements significantly decrease URTIs and asthma exacerbations requiring OCS, there is insufficient data in preschoolers. This study aims to determine the impact of vitamin D₃ supplementation on exacerbations requiring OCS, in preschoolers with recurrent URTI-induced asthma exacerbations.

METHODS AND ANALYSIS

This is a phase III, randomised, triple-blind, placebo-controlled, parallel-group multicentre trial of vitamin D₃ supplementation in children aged 1-5 years, with asthma triggered by URTIs and a recent history of frequent URTIs and OCS use. Children (n=865) will be recruited in the fall and early winter and followed for 7 months. They will be randomised to either the (1) intervention: two oral boluses of 100 000 international unit (IU) vitamin D₃ (3.5 months apart) with 400 IU vitamin D₃ daily; or (2) control: identical placebo boluses with daily placebo. The primary outcome is the number of exacerbations requiring OCS per child, documented by medical and pharmacy records. Secondary outcomes include number of laboratory-confirmed viral URTIs, exacerbation duration and severity, parent functional status, healthcare use, treatment deintensification, cost and safety.

ETHICS AND DISSEMINATION

This study has received ethical approval from all sites. Results will be disseminated via international conferences and manuscripts targeting paediatricians and respirologists, and to families of asthmatic children via our Quebec parents-partners outreach programme. If proven effective, findings may markedly influence the management of URTI-induced asthma in high-morbidity preschoolers and could be directly implemented into practice with an update to clinical guidelines.

TRIAL REGISTRATION NUMBER

NCT03365687.

Vitamin D and Acute Respiratory Infections-The PODA Trial

Background

There is considerable heterogeneity in clinical trials examining the role of vitamin D in the prevention of acute respiratory infections (ARIs).

Methods

The primary aim of the Physical Performance, Osteoporosis, and Vitamin D in Older African-American Women (PODA) trial was the prevention of bone loss and decline in physical performance. A questionnaire about ARIs was administered every 3 months for 3 years to 260 black American women in a double-blind randomized clinical trial that had a placebo group and a vitamin D supplementation group. The serum 25(OH)D level was maintained >30 ng/mL in the vitamin D group.

Results

Serum 25(OH)D was maintained >30 ng/mL in 90% of the active group, whereas levels approximated those associated with the recommended dietary allowance (20 ng/mL) in the placebo group. There was no difference in occurrence of ARIs in the treatment group vs the placebo group. ARIs were not related to total or free 25(OH)D, which were measured at baseline and annually for 36 months.

Conclusions

Vitamin D supplementation sufficient to maintain serum 25(OH)D >30 ng/mL does not prevent ARIs in older African American women.

ClinicalTrialsgov Registration Number

NCT01153568.

Acute Respiratory Tract Infection and 25-Hydroxyvitamin D Concentration: A Systematic Review and Meta-Analysis

Observational studies and randomised controlled studies suggest that vitamin D plays a role in the prevention of acute respiratory tract infection (ARTI); however, findings are inconsistent and the optimal serum 25-hydroxyvitamin D (25(OH)D) concentration remains unclear. To review the link between 25(OH)D concentration and ARTI, we searched PubMed and EMBASE databases to identify observational studies reporting the association between 25(OH)D concentration and risk or severity of ARTI. We used random-effects meta-analysis to pool findings across studies. Twenty-four studies were included in the review, 14 were included in the meta-analysis of ARTI risk and five in the meta-analysis of severity. Serum 25(OH)D concentration was inversely associated with risk and severity of ARTI; pooled odds ratios (95% confidence interval) were 1.83 (1.42-2.37) and 2.46 (1.65-3.66), respectively, comparing the lowest with the highest 25(OH)D category. For each 10 nmol/L decrease in 25(OH)D concentration, the odds of ARTI increased by 1.02 (0.97-1.07). This was a non-linear trend, with the sharpest increase in risk of ARTI occurring at 25(OH)D concentration < 37.5 nmol/L. In conclusion, there is an inverse non-linear association between 25(OH)D concentration and ARTI.

Vitamin D is not required for adaptive immunity to listeria

Although ex vivo research suggests that vitamin D may play a role in innate and adaptive immunity, clear in vivo evidence is lacking. We have tested whether severe vitamin D deficiency alters the ability of mice to resist infection by Listeria. Our results show that vitamin D deficiency does not affect the LD50 of naïve mice in response to Listeria. To study the adaptive immune response, the LD50 for Listeria-immunized mice was determined for vitamin D-deficient and vitamin D-sufficient mice. Although the LD50 clearly increased by immunization with inactivated Listeria, there was no effect of vitamin D deficiency on survival of mice infected with wild-type Listeria. Thus, in this model of adaptive immunity, we could find no evidence of a role for vitamin D.

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.

When and How to Diagnose and Treat Vitamin D Deficiency in Adults: A Practical and Clinical Update

Vitamin D deficiency is considered a major public health concern. Inadequate sun exposure, limited oral intake, and impaired intestinal absorption are common risk factors for vitamin D deficiency. An increasing amount of research is aimed at answering questions regarding the most convenient test that can assess vitamin D status, the indications for screening, and finally the utility of treatments for vitamin D deficiency. Our review outlines practical strategies to diagnose and treat vitamin D deficiency in adults. This study was undertaken in the PubMed and the Google Scholar databases in April 2018 without limitation as to the publication period. Vitamin D status is determined by measuring the 25-hydroxyvitamin D serum concentration. However, this technique has several limitations. Determining the accurate thresholds for vitamin D deficiency is still a matter of debate. Only individuals at risk for vitamin D deficiency should be screened. The symptoms of vitamin D deficiency are unspecific and very common. Therefore, physicians may easily suspect vitamin D deficiency, measure 25-hydroxyvitamin D levels, and sometimes overprescribe supplementation. Hypovitaminosis D could rarely be treated by increasing consumption of foods naturally containing and fortified with vitamin D. Special attention should be given to vitamin D supplementation to prevent adverse effects. No safe and well-defined threshold of ultraviolet exposure allows adequate vitamin D synthesis without increasing the risk of skin cancer. Unanimous and decisive guidelines are urgently needed to improve knowledge and practices related to vitamin D deficiency.

Effect of Higher vs Standard Dosage of Vitamin D3 Supplementation on Bone Strength and Infection in Healthy Infants: A Randomized Clinical Trial

IMPORTANCE

Although guidelines for vitamin D supplementation in infants have been widely implemented, they are mostly based on studies focusing on prevention of rickets. The optimal dose for bone strength and infection prevention in healthy infants remains unclear.

OBJECTIVE

To determine whether daily supplementation with 1200 IU of vitamin D3 increases bone strength or decreases incidence of infections in the first 2 years of life compared with a dosage of 400 IU/d.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial involving a random sample of 975 healthy term infants at a maternity hospital in Helsinki, Finland. Study recruitment occurred between January 14, 2013, and June 9, 2014, and the last follow-up was May 30, 2016. Data analysis was by the intention-to-treat principle.

INTERVENTIONS

Randomization of 489 infants to daily oral vitamin D3 supplementation of 400 IU and 486 infants to 1200 IU from age 2 weeks to 24 months.

MAIN OUTCOMES AND MEASURES

Primary outcomes were bone strength and incidence of parent-reported infections at 24 months.

RESULTS

Of the 975 infants who were randomized, 485 (49.7%) were girls and all were of Northern European ethnicity. Eight hundred twenty-three (84.4%) completed the 24-month follow-up. We found no differences between groups in bone strength measures, including bone mineral content (mean difference, 0.4 mg/mm; 95% CI, -0.8 to 1.6), mineral density (mean difference, 2.9 mg/cm3; 95% CI, -8.3 to 14.2), cross-sectional area (mean difference, -0.9 mm2; 95% CI, -5.0 to 3.2), or polar moment of inertia (mean difference, -66.0 mm4, 95% CI, -274.3 to 142.3). Incidence rates of parent-reported infections did not differ between groups (incidence rate ratio, 1.00; 95% CI, 0.93-1.06). At birth, 914 of 955 infants (95.7%) were vitamin D sufficient (ie, 25-hydroxyvitamin D [25(OH)D] concentration ≥20.03 ng/mL). At 24 months, mean 25(OH)D concentration was higher in the 1200-IU group than in the 400-IU group (mean difference, 12.50 ng/mL; 95% CI, 11.22-13.78).

CONCLUSIONS AND RELEVANCE

A vitamin D3 supplemental dose of up to 1200 IU in infants did not lead to increased bone strength or to decreased infection incidence. Daily supplementation with 400 IU vitamin D3 seems adequate in maintaining vitamin D sufficiency in children younger than 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01723852.

Emerging problems in the treatment of pediatric community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) remains one of the most common reasons for paediatric morbidity and accounts for about 16% of all the deaths occurring in children less than 5 years of age. Areas covered: The main aim of this paper is to discuss the emerging problems for CAP treatment in paediatric age. Expert commentary: Official recommendations for therapeutic approaches to paediatric CAP, despite being not very recent, seem still to be the best solution to assure the highest probabilities of cure for children with this disease living in industrialized countries. Amoxicillin remains the drug of choice and use of macrolides alone or in combination does not seem supported by solid evidence. Corticosteroids can be useful in CAP associated with bronco-obstruction, whereas their effectiveness in cases with a severe inflammatory response, although plausible, is not supported by data collected through randomized, placebo-controlled trials. Finally, for the administration of vitamin C and vitamin D, the available data are not adequate to draw firm conclusions regarding the real importance of supplementation. Further studies are needed to evaluate which modifications of presently available recommendations for paediatric CAP treatment can improve final prognosis of this still common disease.

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.

Vitamin D deficiency in children with recurrent respiratory infections, with or without immunoglobulin deficiency

PURPOSE

The objective of this study was to evaluate thevitamin D concentration in patients with recurrent respiratory infections with or without immunoglobulin G, A or M (IgG, IgA, IgM) deficiency, and to find a correlation between the vitamin D concentration and the response to hepatitis B vaccination.

MATERIALS AND METHOD

The study involved 730 patients with recurrent respiratory infections. The concentration of 25-hydroxyvitamin D (25(OH)D), immunoglobulins G, A and M, anti-HBs was determined.

RESULTS

The tests showed that 11% of patients presented IgG levels below the age related reference values. Children with reduced IgG concentration were also found to have significantly lower vitamin D concentrations in comparison to children with normal IgG. Vitamin D deficiency was observed in schoolchildren between 7 and 18 years of age. No correlation was found between 25(OH)D concentration and Hbs antibody levels.

CONCLUSIONS

An investigation of a large group of patients who have recurrent infection found patients with IgG deficiency to whom special proceeding have to be performed: 1. Significantly lower vitamin D concentration observed in the group of children with IgG deficiency implicated in long-lasting monitoring of vitamin D level require adding to the practice guidelines for Central Europe 2013. 2. Intervention treatment with suitable doses of vitamin D to clarified metabolism of vitamin D has to be plan for children with IgG deficiency and significant lower vitamin D concentration.

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 supplementation decreases immune activation and exhaustion in HIV-1-infected youth

BACKGROUND

Heightened immune activation and exhaustion drive HIV disease progression and comorbidities. Vitamin D has pleiotropic immunomodulatory effects, but little is known about the effects of supplementation in HIV. Our study investigates changes in immune activation and exhaustion markers after 12 months of supplementation in virologically suppressed HIV-infected youth with vitamin D insufficiency.

METHODS

This is a randomized, active-control, double-blind trial investigating with three different vitamin D3 doses (18,000 [standard/active-control dose], 60,000 [moderate dose] and 120,000 IU/month [high dose]) in 8-25-year-old HIV-infected youth on combination antiretroviral therapy with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations ≤30 ng/ml. Only subjects (n=51) who maintained an undetectable HIV-1 RNA over the 12-month study period were included in this analysis.

RESULTS

Baseline serum 25(OH)D concentrations and immune activation/exhaustion markers were not different between groups. By 12 months, 25(OH)D increased significantly within each dosing group with the greatest increase and most sustained concentrations ≥30 ng/ml in the high-dose group. Overall, all measured markers decreased with CD4 activation (CD4+CD38+HLA-DR+), CD8 activation (CD8+CD38+HLA-DR+), CD4 exhaustion (CD4+CD38+HLA-DR+PD1+) and inflammatory monocytes (CD14+CD16+) reaching statistical significance. When analysed separately, there were no significant decreases in the moderate- or standard-dose groups, but CD4 and CD8 activation and inflammatory monocytes decreased significantly in the high-dose group.

CONCLUSIONS

Vitamin D supplementation decreased markers of T-cell activation/exhaustion and monocyte activation in HIV-infected youth, with subjects given the highest dose (120,000 IU/month) showing the greatest decreases. These data suggest that high-dose vitamin D supplementation may attenuate immune activation and exhaustion, and serve as adjuvant therapy to antiretroviral therapy in HIV. ClinicalTrials.gov identifier: NCT01523496.

Effects of Vitamin D Supplementation on Bone Mineral Density and Bone Markers in HIV-Infected Youth

BACKGROUND

Low bone mineral density (BMD) is a significant comorbidity in HIV. However, studies evaluating vitamin D supplementation on bone health in this population are limited. This study investigates changes in bone health parameters after 12 months of supplementation in HIV-infected youth with vitamin D insufficiency.

METHODS

This is a randomized, active-control, double-blind trial investigating changes in bone parameters with 3 different vitamin D3 doses [18,000 (standard/control dose), 60,000 (moderate dose), and 120,000 IU/monthly (high dose)] in HIV-infected youth 8-25 years old with baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations <30 ng/mL. BMD and bone turnover markers were measured at baseline and 12 months.

RESULTS

One hundred two subjects enrolled. Over 12 months, serum 25(OH)D concentrations increased with all doses, but the high dose (ie, 120,000 IU/monthly) maintained serum 25(OH)D concentrations in an optimal range (≥30 or ≥20 ng/mL) throughout the study period for more subjects (85% and 93%, respectively) compared with either the moderate (54% and 88%, respectively) or standard dose (63% and 80%, respectively). All dosing groups showed some improvement in BMD; however, only the high-dose arm showed significant decreases in bone turnover markers for both procollagen type 1 aminoterminal propeptide (-3.7 ng/mL; P = 0.001) and Β-CrossLaps (-0.13 ng/mL; P = 0.0005).

CONCLUSIONS

High-dose vitamin D supplementation (120,000 IU/mo) given over 12 months decreases bone turnover markers in HIV-infected youth with vitamin D insufficiency, which may represent an early, beneficial effect on bone health. High vitamin D doses are needed to maintain optimal serum 25(OH)D concentrations.

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; pinteraction=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).

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

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

Role of vitamin D in cystic fibrosis and non-cystic fibrosis bronchiectasis

Bronchiectasis is usually classified as cystic fibrosis (CF) related or CF unrelated (non-CF); the latter is not considered an orphan disease any more, even in developed countries. Irrespective of the underlying etiology, bronchiectasis is the result of interaction between host, pathogens, and environment. Vitamin D is known to be involved in a wide spectrum of significant immunomodulatory effects such as down-regulation of pro-inflammatory cytokines and chemokines. Respiratory epithelial cells constitutively express 1α-hydroxylase leading to the local transformation of the inactive 25(OH)-vitamin D to the active 1,25(OH)₂-vitamin D. The latter through its autocrine and paracrine functions up-regulates vitamin D dependent genes with important consequences in the local immunity of lungs. Despite the scarcity of direct evidence on the involvement of vitamin D deficiency states in the development of bronchiectasis in either CF or non-CF patients, it is reasonable to postulate that vitamin D may play some role in the pathogenesis of lung diseases and especially bronchiectasis. The potential contribution of vitamin D deficiency in the process of bronchiectasis is of particular clinical importance, taking into consideration the increasing prevalence of vitamin D deficiency worldwide and the significant morbidity of bronchiectasis. Given the well-established association of vitamin D deficiency with increased inflammation, and the indicative evidence for harmful consequences in lungs, it is intriguing to speculate that the administration of vitamin D supplementation could be a reasonable and cost effective supplementary therapeutic approach for children with non-CF bronchiectasis. Regarding CF patients, maybe in the future as more data become available, we have to re-evaluate our policy on the most appropriate dosage scheme for vitamin D.

Modulation of inflammatory and immune responses by vitamin D

Vitamin D (VitD) is a prohormone most noted for the regulation of calcium and phosphate levels in circulation, and thus of bone metabolism. Inflammatory and immune cells not only convert inactive VitD metabolites into calcitriol, the active form of VitD, but also express the nuclear receptor of VitD that modulates differentiation, activation and proliferation of these cells. In vitro, calcitriol upregulates different anti-inflammatory pathways and downregulates molecules that activate immune and inflammatory cells. Administration of VitD has beneficial effects in a number of experimental models of autoimmune disease. Epidemiologic studies have indicated that VitD insufficiency is frequently associated with immune disorders and infectious diseases, exacerbated by increasing evidence of suboptimal VitD status in populations worldwide. To date, however, most interventional studies in human inflammatory and immune diseases with VitD supplementation have proven to be inconclusive. One of the reasons could be that the main VitD metabolite measured in these studies was the 25-hydroxyVitD (25OHD) rather than its active form calcitriol. Although our knowledge of calcitriol as modulator of immune and inflammatory reactions has dramatically increased in the past decades, further in vivo and clinical studies are needed to confirm the potential benefits of VitD in the control of immune and inflammatory conditions.

Effect of High-Dose vs Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy Children

IMPORTANCE

Epidemiological studies support a link between low 25-hydroxyvitamin D levels and a higher risk of viral upper respiratory tract infections. However, whether winter supplementation of vitamin D reduces the risk among children is unknown.

OBJECTIVE

To determine whether high-dose vs standard-dose vitamin D supplementation reduces the incidence of wintertime upper respiratory tract infections in young children.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial was conducted during the winter months between September 13, 2011, and June 30, 2015, among children aged 1 through 5 years enrolled in TARGet Kids!, a multisite primary care practice-based research network in Toronto, Ontario, Canada.

INTERVENTIONS

Three hundred forty-nine participants were randomized to receive 2000 IU/d of vitamin D oral supplementation (high-dose group) vs 354 participants who were randomized to receive 400 IU/d (standard-dose group) for a minimum of 4 months between September and May.

MAIN OUTCOME MEASURES

The primary outcome was the number of laboratory-confirmed viral upper respiratory tract infections based on parent-collected nasal swabs over the winter months. Secondary outcomes included the number of influenza infections, noninfluenza infections, parent-reported upper respiratory tract illnesses, time to first upper respiratory tract infection, and serum 25-hydroxyvitamin D levels at study termination.

RESULTS

Among 703 participants who were randomized (mean age, 2.7 years, 57.7% boys), 699 (99.4%) completed the trial. The mean number of laboratory-confirmed upper respiratory tract infections per child was 1.05 (95% CI, 0.91-1.19) for the high-dose group and 1.03 (95% CI, 0.90-1.16) for the standard-dose group, for a between-group difference of 0.02 (95% CI, -0.17 to 0.21) per child. There was no statistically significant difference in number of laboratory-confirmed infections between groups (incidence rate ratio [RR], 0.97; 95% CI, 0.80-1.16). There was also no significant difference in the median time to the first laboratory-confirmed infection: 3.95 months (95% CI, 3.02-5.95 months) for the high-dose group vs 3.29 months (95% CI, 2.66-4.14 months) for the standard-dose group, or number of parent-reported upper respiratory tract illnesses between groups (625 for high-dose vs 600 for standard-dose groups, incidence RR, 1.01; 95% CI, 0.88-1.16). At study termination, serum 25-hydroxyvitamin D levels were 48.7 ng/mL (95% CI, 46.9-50.5 ng/mL) in the high-dose group and 36.8 ng/mL (95% CI, 35.4-38.2 ng/mL) in the standard-dose group.

CONCLUSIONS AND RELEVANCE

Among healthy children aged 1 to 5 years, daily administration of 2000 IU compared with 400 IU of vitamin D supplementation did not reduce overall wintertime upper respiratory tract infections. These findings do not support the routine use of high-dose vitamin D supplementation in children for the prevention of viral upper respiratory tract infections.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01419262.

Non-skeletal health effects of vitamin D supplementation: A systematic review on findings from meta-analyses summarizing trial data

BACKGROUND

A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D (25OHD) levels on non-skeletal outcomes. We performed a systematic quantitative review on characteristics of randomized clinical trials (RCTs) included in meta-analyses (MAs) on non-skeletal effects of vitamin D supplementation.

METHODS AND FINDINGS

We identified systematic reviews (SR) reporting summary data in terms of MAs of RCTs on selected non-skeletal outcomes. For each outcome, we summarized the results from available SRs and scrutinized included RCTs for a number of predefined characteristics. We identified 54 SRs including data from 210 RCTs. Most MAs as well as the individual RCTs reported null-findings on risk of cardiovascular diseases, type 2 diabetes, weight-loss, and malignant diseases. Beneficial effects of vitamin D supplementation was reported in 1 of 4 MAs on depression, 2 of 9 MAs on blood pressure, 3 of 7 MAs on respiratory tract infections, and 8 of 12 MAs on mortality. Most RCTs have primarily been performed to determine skeletal outcomes, whereas non-skeletal effects have been assessed as secondary outcomes. Only one-third of the RCTs had low level of 25OHD as a criterion for inclusion and a mean baseline 25OHD level below 50 nmol/L was only present in less than half of the analyses.

CONCLUSIONS

Published RCTs have mostly been performed in populations without low 25OHD levels. The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels.

Strategies to alter the natural history of childhood asthma

PURPOSE OF REVIEW

Asthma exhibits significant heterogeneity in occurrence and severity over the lifespan. Our goal is to discuss recent evidence regarding determinants of the natural history of asthma during childhood, and review the rationale behind and status of major efforts to alter its course.

RECENT FINDINGS

Variations in microbial exposures are associated with risk of allergic disease, and the use of bacterial lysates may be a promising preventive strategy. Exposure to air pollution appears to be particularly damaging in prenatal and early life, and interventions to reduce pollution are feasible and result in clinical benefit. E-cigarette use may have a role in harm reduction for conventional cigarette smokers with asthma, but has undefined short-term and long-term effects that must be clarified. Vitamin D insufficiency over the first several years of life is associated with risk of asthma, and vitamin D supplementation reduces the risk of severe exacerbations.

SUMMARY

The identification of risk factors for asthma occurrence, persistence and severity will continue to guide efforts to alter the natural history of the disease. We have reviewed several promising strategies that are currently under investigation. Vitamin D supplementation and air pollution reduction have been shown to be effective strategies and warrant increased investigation and implementation.

The Likelihood of Preventing Respiratory Exacerbations in Children and Adolescents with either Chronic Suppurative Lung Disease or Bronchiectasis

Chronic suppurative lung disease (CSLD) and bronchiectasis in children and adolescents are important causes of respiratory morbidity and reduced quality of life (QoL), also leading to subsequent premature death during adulthood. Acute respiratory exacerbations in pediatric CSLD and bronchiectasis are important markers of disease control clinically, given that they impact upon QoL and increase health-care-associated costs and can adversely affect future lung functioning. Preventing exacerbations in this population is, therefore, likely to have significant individual, familial, societal, and health-sector benefits. In this review, we focus on therapeutic interventions, such as drugs (antibiotics, mucolytics, hyperosmolar agents, bronchodilators, corticosteroids, non-steroidal anti-inflammatory agents), vaccines and physiotherapy, and care-planning, such as post-hospitalization management and health promotion strategies, including exercise, diet, and reducing exposure to environmental toxicants. The review identified a conspicuous lack of moderate or high-quality evidence for preventing respiratory exacerbations in children and adolescents with CSLD or bronchiectasis. Given the short- and long-term impact of exacerbations upon individuals, their families, and society as a whole, large studies addressing interventions at the primary and tertiary prevention phases are required. This research must include children and adolescents in both developing and developed countries and address long-term health outcomes.