Vitamin D3 supplementation in patients with chronic obstructive pulmonary disease (ViDiCO): a multicentre, double-blind, randomised controlled trial

Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of stratified aggregate data

BACKGROUND

A 2021 meta-analysis of 37 randomised controlled trials (RCTs) of vitamin D supplementation for prevention of acute respiratory infections (ARIs) revealed a statistically significant protective effect of the intervention (odds ratio [OR] 0·92 [95% CI 0·86 to 0·99]). Since then, six eligible RCTs have been completed, including one large trial (n=15 804). We aimed to re-examine the link between vitamin D supplementation and prevention of ARIs.

METHODS

Updated systematic review and meta-analysis of data from RCTs of vitamin D for ARI prevention using a random effects model. Subgroup analyses were done to determine whether effects of vitamin D on risk of ARI varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration, dosing regimen, or age. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and the ClinicalTrials.gov between May 1, 2020 (end-date of search of our previous meta-analysis) and April 30, 2024. No language restrictions were imposed. Double-blind RCTs supplementing vitamin D for any duration, with placebo or lower-dose vitamin D control, were eligible if approved by a Research Ethics Committee and if ARI incidence was collected prospectively and pre-specified as an efficacy outcome. Aggregate data, stratified by baseline 25(OH)D concentration and age, were obtained from study authors. The study was registered with PROSPERO (no. CRD42024527191).

FINDINGS

We identified six new RCTs (19 337 participants). Data were obtained for 16 085 (83·2%) participants in three new RCTs and combined with data from 48 488 participants in 43 RCTs identified in our previous meta-analysis. For the primary comparison of any vitamin D versus placebo, the intervention did not statistically significantly affect overall ARI risk (OR 0·94 [95% CI 0·88-1·00], p=0·057; 40 studies; 61 589 participants; I2=26·4%). Pre-specified subgroup analysis did not reveal evidence of effect modification by age, baseline vitamin D status, dosing frequency, or dose size. Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (OR 0·96 [95% CI 0·90-1·04]; 38 studies; I2=0·0%). A funnel plot showed left-sided asymmetry (p=0·0020, Egger's test).

INTERPRETATION

This updated meta-analysis yielded a similar point estimate for the overall effect of vitamin D supplementation on ARI risk to that obtained previously, but the 95% CI for this effect estimate now includes 1·00, indicating no statistically significant protection.

FUNDING

None.

Nonlinear association between serum 25-hydroxyvitamin D concentrations and lung function in the United States adult population with COPD

Vitamin D has been studied for its potential protective effects against lung function decline in patients with COPD. However, conflicting results exist, the actual effect of vitamin D on lung function remains controversial. This study aimed to determine whether serum 25-hydroxyvitamin D (25-OHD) levels are correlated with lung function in community-dwelling individuals with COPD. We used data from the National Health and Nutrition Examination Survey (NHANES) to explore the relationship between serum 25-OHD concentration and the severity of airflow obstruction. Multivariable logistic regression, stratified analysis with interaction, restricted cubic splines (RCS), and threshold effect analysis were used to investigate the association between serum 25-OHD concentration and lung function.A total of 1384 patients with COPD were analyzed. Accordingly, the association between serum 25-OHD concentrations and lung function exhibited an inverse L-shaped curve in the RCS. Threshold analysis showed that in participants with 25-OHD concentrations < 90 nmol/L, lung function decreased with decrease in serum 25-OHD concentrations, whereas no significant association was observed in those with serum 25-OHD concentrations ≥ 90 nmol/L. An inverse L-shaped relationship was observed between serum 25-OHD concentration and airflow obstruction severity in the adult population with COPD in the United States.

The Synergic Immunomodulatory Effect of Vitamin D and Chickpea Protein Hydrolysate in THP-1 Cells: An In Vitro Approach

Vitamin D (VD), a crucial micronutrient, regulates bone health and immune responses. Recent studies suggest that VD may confer protective effects against chronic inflammatory diseases. Additionally, plant-based peptides can show biological activities. Furthermore, the supplementation of protein hydrolysates with VD could potentially enhance the bioactivity of peptides, leading to synergistic effects. In this study, THP-1 cells were exposed to low concentrations of Lipopolysaccharide (LPS) to induce inflammation, followed by treatment with vitamin D at different concentrations (10, 25, or 50 nM) or a chickpea protein hydrolysate ("H30BIO") supplemented with VD. The cytotoxicity of VD was evaluated using viability assay to confirm its safety. The cytokine secretion of TNF-α, IL-1β, and IL6 was assessed in the cell supernatant, and the gene expression of TNF-α, IL-1β, IL6, IL8, CASP-1, COX2, NRF2, NF-ĸB, NLRP3, CCL2, CCR2, IP10, IL10, and RANTES was quantified by qRT-PCR. Treatment with VD alone significantly decreased the expression of the pro-inflammatory genes TNF-α and IL6, as well as their corresponding cytokine levels in the supernatants. While IL-1β gene expression remained unchanged, a reduction in its cytokine release was observed upon VD treatment. No dose-dependent effects were observed. Interestingly, the combination of VD with H30BIO led to an increase in TNF-α expression and secretion in contrast with the LPS control, coupled with a decrease in IL-1β levels. Additionally, genes such as IP10, NF-κB, CCL2, COX2, NRF2, and CASP-1 exhibited notable modulation, suggesting that the combination treatment primarily downregulates NF-κB-related gene activity. This study demonstrates a synergistic interaction between VD and H30BIO, suggesting that this combination may enhance pathways involving TNF-α, potentially aiding in the resolution and modulation of inflammation through adaptive processes. These findings open new avenues for research into the therapeutic applications of enriched protein hydrolysates with VD to manage low-grade inflammatory-related conditions.

Vitamin D for the management of chronic obstructive pulmonary disease

BACKGROUND

COPD is a common, preventable and treatable airway disease, and is currently the third leading cause of death worldwide. About one billion people worldwide are estimated to have vitamin D deficiency or insufficiency. Vitamin D deficiency is common among people with COPD, and has been reported to be associated with reduced lung function and increased risk of acute exacerbations of COPD. Several clinical trials of vitamin D to prevent acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and improve COPD control have been conducted, but an up-to-date meta-analysis of all double-blind, randomised, placebo-controlled trials of this intervention is lacking.

OBJECTIVES

To assess the effects of vitamin D for the management of acute exacerbations and symptoms for people with COPD.

SEARCH METHODS

We searched the Cochrane Airways Trials Register and reference lists of articles. We also searched trial registries directly, and contacted the authors of studies in order to identify additional trials. The date of the last search was 24 August 2022.

SELECTION CRITERIA

We included double-blind, randomised, placebo-controlled trials of vitamin D or its hydroxylated metabolites, for adults with a clinical diagnosis of chronic obstructive pulmonary disease based on the presence of characteristic symptoms and irreversible airflow obstruction. We did not impose restrictions regarding disease severity or baseline vitamin D status, in order to maximise generalisability.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. The primary outcome was the rate of moderate or severe exacerbations (requiring systemic corticosteroids, antibiotics or both). We also performed subgroup analyses to determine whether the effect of vitamin D on the rate of moderate or severe exacerbations was modified by baseline vitamin D status, COPD severity or regular inhaled corticosteroid use. The main secondary outcomes of interest were the proportion of participants experiencing one or more exacerbations (moderate or severe), the change in forced expiratory volume in one second (FEV1, % predicted) and the proportion of participants with one or more serious adverse events of any cause, mortality (all-cause) and quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included 10 double-blind, randomised, placebo-controlled trials in this review, involving a total of 1372 adults. Five studies contributed to the primary outcome analysis of the rate of moderate or severe exacerbations requiring systemic corticosteroids, antibiotics or both. The duration of studies ranged from six weeks to 40 months, and all investigated the effects of administering cholecalciferol (vitamin D3). One study included two intervention arms, one where vitamin D3 was given and one where calcitriol (1,25-dihydroxyvitamin D) was given. The majority of participants had mild to moderate COPD, and profound vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25 nmol/L) at baseline was rare (123 participants contributing data to subgroup analysis). Administration of vitamin D or its hydroxylated metabolites results in little to no change in the overall rate of exacerbations requiring systemic corticosteroids, antibiotics or both (rate ratio (RR) 0.98, 95% CI 0.86 to 1.11; 5 studies, 980 participants; high-certainty evidence). Vitamin D supplementation did not influence any meta-analysed secondary outcomes. These were all based on moderate- or high-certainty evidence aside from adverse events and quality of life, which were based on low-certainty evidence. We observed little to no change in the proportion of participants experiencing one or more moderate or severe exacerbations (odds ratio (OR) 0.94, 95% CI 0.72 to 1.24; 5 studies, 980 participants; high-certainty evidence). Additionally, vitamin D probably results in little to no difference in the inter-arm mean change in FEV1 (% predicted) (mean difference 2.82 higher in intervention arm, 95% CI -2.42 to 8.06; 7 studies, 1063 participants; moderate-certainty evidence). There was also probably no effect of vitamin D on the incidence of serious adverse events due to any cause; although we identified an anticipated absolute effect of 36 additional adverse events per 1000 people, the confidence interval included the null hypothesis of no effect (OR 1.19, 95% CI 0.82 to 1.71; 5 studies, 663 participants; moderate-certainty evidence). Vitamin D may have little to no effect on mortality (OR 1.13, 95% CI 0.57 to 2.21; 6 studies, 1019 participants; low-certainty evidence). It also may have little to no effect on quality of life as measured by validated instruments (narrative findings; 5 studies, 663 participants; low-certainty evidence). We assessed one study as being at high risk of bias in at least one domain; this did not contribute data to the meta-analysis of the primary outcome reported above. Sensitivity analysis that excluded this study from the meta-analysed outcome to which it contributed, the inter-arm mean change in FEV1, did not change the findings.

AUTHORS' CONCLUSIONS

We found that administration of vitamin D results in little to no effect on the rate of moderate or severe exacerbations requiring systemic corticosteroids, antibiotics or both or the proportion of participants experiencing one or more exacerbations (moderate or severe) (both high-certainty evidence). Further, vitamin D probably has no effect on the inter-arm difference in change in lung volumes and the proportion of participants with one or more serious adverse event of any cause (both moderate-certainty evidence), and may make little to no difference to mortality or quality of life (both low-certainty evidence). We recommend further research on the balance of benefits and harms of vitamin D supplements in COPD for those with very low or very high starting vitamin D levels, because we assessed the available evidence as low-certainty for these groups.

Optimal methods of vitamin D supplementation to prevent acute respiratory infections: a systematic review, dose-response and pairwise meta-analysis of randomized controlled trials

BACKGROUND

Vitamin D supplementation may prevent acute respiratory infections (ARIs). This study aimed to identify the optimal methods of vitamin D supplementation.

METHODS

PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and the ClinicalTrials.gov registry were searched from database inception through July 13, 2023. Randomized-controlled trials (RCTs) were included. Data were pooled using random-effects model. The primary outcome was the proportion of participants with one or more ARIs.

RESULTS

The analysis included 43 RCTs with 49320 participants. Forty RCTs were considered to be at low risk for bias. The main pairwise meta-analysis indicated there were no significant preventive effects of vitamin D supplementation against ARIs (risk ratio [RR]: 0.99, 95% confidence interval [CI]: 0.97 to 1.01, I2 = 49.6%). The subgroup dose-response meta-analysis indicated that the optimal vitamin D supplementation doses ranged between 400-1200 IU/day for both summer-sparing and winter-dominant subgroups. The subgroup pairwise meta-analysis also revealed significant preventive effects of vitamin D supplementation in subgroups of daily dosing (RR: 0.92, 95% CI: 0.85 to 0.99, I2 = 55.7%, number needed to treat [NNT]: 36), trials duration < 4 months (RR: 0.81, 95% CI: 0.67 to 0.97, I2 = 48.8%, NNT: 16), summer-sparing seasons (RR: 0.85, 95% CI: 0.74 to 0.98, I2 = 55.8%, NNT: 26), and winter-dominant seasons (RR: 0.79, 95% CI: 0.71 to 0.89, I2 = 9.7%, NNT: 10).

CONCLUSION

Vitamin D supplementation may slightly prevent ARIs when taken daily at doses between 400 and 1200 IU/d during spring, autumn, or winter, which should be further examined in future clinical trials.

Mechanisms of osteoporosis associated with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a disease characterized by chronic respiratory symptoms due to inflammatory and destructive changes of the lung leading to progressive airflow obstruction. Fragility fractures associated with osteoporosis are among major comorbidities and have significant impacts on quality of life and prognosis of patients with COPD. Evidence suggests that both decreased bone mineral density (BMD) and impaired bone quality contribute to bone fragility and resultant fractures in COPD. Although various clinical risk factors of osteoporosis have been described, mechanisms of COPD-associated osteoporosis are still largely unknown. In addition, its specific treatment has not been established, either. Previous studies have suggested involvement of low BMI and sarcopenia in the pathogenesis of COPD-associated osteoporosis. In this narrative review, we will propose critical roles of vitamin D deficiency and inflammation, both of which are often present in COPD and may underlie the development of osteosarcopenia and impaired bone quality, ultimately causing fractures in COPD patients.

Effect of Macronutrients or Micronutrients Supplementation on Nutritional Status, Physical Functional Capacity and Quality of Life in Patients with COPD: A Systematic Review and Meta-Analysis

Given the importance that a correct and balanced nutrition has on patients with chronic obstructive pulmonary disease (COPD), supplementation of macro and micronutrients has been proposed, but the results of previous meta-analyses are contrasting. We performed an update of the latest evidence through a systematic review and meta-analysis of studies to assess the role of nutritional supplements in improving nutritional status, pulmonary function, physical performance, and quality of life of these patients.We included randomized controlled trials (RCTs) published between 01-01-2010 and 11-01-2023 evaluating the effectiveness of nutritional support in patients affected by stable COPD with an intervention of at least 2 weeks. Primary outcomes were changes in body mass index (BMI) and fat free mass index (FFMI). Secondary outcomes were exercise tolerance (6-min walking test, 6MWT), quality of life (St George's Respiratory Questionnaire, SGRQ) and respiratory function (FEV1). According with supplements type (macronutrients or micronutrients), we calculated the pooled adjusted mean difference (MD) and 95% confidence intervals (95%CIs) of the selected outcomes, using random-effects models in presence of high heterogeneity (I2>50%) or fixed-effects models otherwise. The risk of publication bias was evaluated with the trim and fill method.From 967 articles, 20 RCTs were included. Macronutrients supplementation improved BMI (MD 1.0 kg/m2, 95%CI 0.21-1.79), FFMI (MD 0.77 Kg/m2, 95%CI 0.48-1.06), 6MQT (MD 68.39 m, 95%CI 40.07-96.71), and SGRQ (MD -5.14, 95% CI -7.31-2.97), while it does not ameliorate respiratory function (MD 0.26% 95%CI -1.87-2.40). Micronutrients supplementation alone did not improve any of the considered outcomes.

Association of Severe Vitamin D Deficiency with Hospitalization in the Previous Year in Hospitalized Exacerbated COPD Patients

Purpose

Vitamin D deficiency (VDD, 25-hydroxyvitamin D < 20 ng/mL) has been reported associated with exacerbation of chronic obstructive pulmonary disease (COPD) but sometimes controversial. Research on severe vitamin D deficiency (SVDD, 25-hydroxyvitamin D < 10 ng/mL) in exacerbation of COPD is limited.

Patients and Methods

We performed a retrospective observational study in 134 hospitalized exacerbated COPD patients. 25-hydroxyvitamin D was modeled as a continuous or dichotomized (cutoff value: 10 or 20 ng/mL) variable to evaluate the association of SVDD with hospitalization in the previous year. Receiver operator characteristic (ROC) analysis was performed to find the optimal cut-off value of 25-hydroxyvitamin D.

Results

In total 23% of the patients had SVDD. SVDD was more prevalent in women, and SVDD group tended to have lower blood eosinophils counts. 25-hydroxyvitamin D level was significantly lower in patients who were hospitalized in the previous year (13.6 vs 16.7 ng/mL, P = 0.044), and the prevalence of SVDD was higher (38.0% vs 14.3%, P = 0.002). SVDD was independently associated with hospitalization in the previous year [odds ratio (OR) 4.34, 95% CI 1.61-11.72, P = 0.004] in hospitalized exacerbated COPD patients, whereas continuous 25-hydroxyvitamin D and VDD were not (P = 0.1, P = 0.9, separately). The ROC curve yielded an area under the curve of 0.60 (95% CI 0.50-0.71) with an optimal 25-hydroxyvitamin D cutoff of 10.4 ng/mL.

Conclusion

SVDD probably showed a more stable association with hospitalization in the previous year in hospitalized exacerbated COPD patients. Reasons for lower eosinophil counts in SVDD group needed further exploration.

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).

The Power of Vitamin D: Is the Future in Precision Nutrition through Personalized Supplementation Plans?

In the last few decades, vitamin D has undeniably been one of the most studied nutrients. Despite our ability to produce vitamin D through sunlight exposure, its presence in several natural food sources and fortified foods, and its widespread availability as a dietary supplement, vitamin D deficiency is a serious public health problem, affecting nearly 50% of the global population. Low serum levels of vitamin D are being associated with increased susceptibility to numerous health conditions, including respiratory infections, mental health, autoimmune diseases, and different cancer types. Although the association between vitamin D status and health is well-established, the exact beneficial effects of vitamin D are still inconclusive and indefinite, especially when considering the prevention and treatment of different health conditions and the determination of an appropriate dosage to exert those beneficial effects in various population groups. Therefore, further research is needed. With constant improvements in our understanding of individual variations in vitamin D metabolism and requirements, in the future, precision nutrition and personalized supplementation plans could prove beneficial.

The Non-conventional Effects of Hypovitaminosis D: A Pandemic Even in Sunlight-Rich Countries

The synthesis and absorption of Vitamin D play crucial roles in numerous bodily functions, yet deficiencies persist due to factors like insufficient sunlight exposure and dietary inadequacy. Research underscores the significance of lifestyle elements such as diet, sun exposure, and physical activity in maintaining optimal Vitamin D levels. Strategies aimed at tackling deficiencies emphasize supplementation alongside lifestyle adjustments, especially in regions with abundant sunlight like the Middle East and North Africa (MENA). Despite the abundance of sunshine in the Arab world, there remains a prevalent issue of Vitamin D deficiency. This problem arises from various factors, including cultural practices such as traditional clothing covering most skin areas, which limit sun exposure, and environmental factors like air pollution that reduce UV penetration. Dietary habits and lifestyle choices also contribute to this deficiency. Dealing with the ongoing pandemic requires a focused effort to enhance awareness. While some individuals may recognize common diseases caused by Vitamin D deficiency, such as rickets and osteomalacia, many remain unaware of the broader health risks associated with the condition, including non-skeletal manifestations. Additionally, there is a lack of understanding regarding the numerous hidden benefits of this hormone. Therefore, prioritizing educational initiatives that delve into these aspects is essential to effectively combat the current health crisis. This literature review aims to report both skeletal and extraskeletal consequences of hypovitaminosis and briefly discuss the cause of paradoxical vitamin D deficiency in sunny regions like the MENA. This was done by reviewing pertinent articles published between January 2000 and January 2024, sourced from databases such as PubMed, UpToDate, Scopus, and CINAHL, focusing exclusively on English language literature and using keywords such as "Vitamin D deficiency" and "Extraskeletal manifestations."

Vitamin D supplementation may be beneficial in improving the prognosis of patients with chronic obstructive pulmonary disease in the intensive care unit: a retrospective study

Background

Vitamin D is a crucial fat-soluble vitamin that has garnered significant attention due to its potential impact on respiratory health. It is noteworthy that many patients with chronic obstructive pulmonary disease (COPD) often experience deficiencies or insufficiencies of vitamin D. To address this issue, our retrospective study aimed to explore the potential association between serum 25-hydroxyvitamin D concentration and the prognoses of COPD patients in the Intensive Care Unit (ICU).

Methods

This study utilised data from the Medical Information Marketplace in Intensive Care IV (MIMIC-IV), a database of patients admitted to the Intensive Care Unit at Beth Israel Deaconess Medical Center (BIDMC) in the United States of America, with a focus on patients with a diagnosis of COPD. These patients were categorized into two groups: those who received vitamin D supplementation during their ICU stay and those who did not. We assessed in-hospital mortality and ICU mortality outcomes. Our analysis involved various analytical tools, including Kaplan-Meier survival curves, Cox proportional risk regression models, and subgroup analyses, to investigate the relationship between vitamin D supplementation and these outcomes. Additionally, we employed propensity-score matching (PSM) to enhance the reliability of our findings.

Results

The study included a total of 3,203 COPD patients, with 587 in the vitamin D group and 2,616 in the no-vitamin D group. The Kaplan-Meier survival curve demonstrated a significant difference in survival probability between the two groups. After adjusting for potential confounders using Cox regression models, the vitamin D group exhibited a substantially lower risk of in-hospital and ICU mortalities compared to the no-vitamin D group. The hazard ratios for in-hospital and ICU mortalities in the vitamin D group were 1.7 (95% CI: 1.3, 2.3) and 1.8 (95% CI: 1.2, 2.6), respectively. Propensity-score matching (PSM) estimation yielded consistent results. Furthermore, in the subgroup analysis, female patients who received vitamin D supplementation showed a reduced risk of in-hospital mortality.

Conclusion

The study suggests that vitamin D supplementation may be linked to a reduction in in-hospital and ICU mortalities among COPD patients in the ICU. Of particular note is the potential benefit observed in terms of in-hospital mortality, especially for female patients.

Analyses of Factors Associated with Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Review

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is the exacerbation of a range of respiratory symptoms during the stable phase of chronic obstructive pulmonary disease (COPD). AECOPD is thus a dangerous stage and key event in the course of COPD, as its deterioration and frequency seriously affects the quality of life of patients and shortens their survival. Acute exacerbations occur and develop due to many factors such as infection, tobacco smoke inhalation, air pollution, comorbidities, airflow limitation, various biomarkers, history of previous deterioration, natural killer cell abnormalities, immunoglobulin G deficiency, genetics, abnormal muscle and nutritional status, negative psychology, and seasonal temperature changes. There is relatively limited research on the impact of the role of standardized management on the alleviation of AECOPD. However, with the establishment of relevant prevention and management systems and the promotion of artificial intelligence technology and Internet medical approaches, long-term effective and standardized management of COPD patients may help to achieve the quality of life and disease prognosis in COPD patients and reduce the risk of AE.

Joint association of sedentary behavior and vitamin D status with mortality among cancer survivors

BACKGROUND

Sedentary behavior and vitamin D deficiency are independent risk factors for mortality in cancer survivors, but their joint association with mortality has not been investigated.

METHODS

We analyzed data from 2914 cancer survivors who participated in the National Health and Nutrition Examination Survey (2007-2018) and followed up with them until December 31, 2019. Sedentary behavior was assessed by self-reported daily hours of sitting, and vitamin D status was measured by serum total 25-hydroxyvitamin D (25(OH)D) levels.

RESULTS

Among 2914 cancer survivors, vitamin D deficiency was more prevalent in those with prolonged daily sitting time. During up to 13.2 years (median, 5.6 years) of follow-up, there were 676 deaths (cancer, 226; cardiovascular disease, 142; other causes, 308). The prolonged sitting time was associated with a higher risk of all-cause and noncancer mortality, and vitamin D deficiency was associated with a higher risk of all-cause and cancer mortality. Furthermore, cancer survivors with both prolonged sitting time (≥ 6 h/day) and vitamin D deficiency had a significantly higher risk of all-cause (HR, 2.05; 95% CI: 1.54-2.72), cancer (HR, 2.33; 95% CI, 1.47-3.70), and noncancer mortality (HR, 1.91; 95% CI, 1.33-2.74) than those with neither risk factor after adjustment for potential confounders.

CONCLUSIONS

In a nationally representative sample of U.S. cancer survivors, the joint presence of sedentary behavior and vitamin D deficiency was significantly associated with an increased risk of all-cause and cancer-specific mortality.

Negligible effect of vitamin D supplementation on exacerbation in patients with chronic obstructive pulmonary disease: meta-analysis

Introduction

The focus of this meta-analysis was how vitamin D supplementation influences exacerbations in patients with chronic obstructive pulmonary disease (COPD) and vitamin D deficiency (VDD).

Materials and methods

Cochrane Library, Web of Science, Embase, and PubMed databases have been systematically searched in an attempt to collect randomized controlled trials related to vitamin D supplementation in COPD patients with VDD published in English available by July 2022. Primary outcome indicators included the mean number of exacerbation and rate of exacerbation. Secondary outcome indicators included forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity (FVC) ratio, and serum 25-hydroxyvitamin D (25(OH)D) concentration.

Results

Five studies involving 522 COPD patients with VDD (defined as 25(OH)D < 50 nmol/L) were included, among them 61 were severely deficient in vitamin D (25(OH)D < 25 nmol/L). The results showed that vitamin D supplementation did not decrease the mean number of exacerbation (standardized mean difference (SMD): - 0.10, 95% CI: - 0.29 to 0.09) and the rate of exacerbation (relative risk (RR): 0.89, 95% CI: 0.76 to 1.04, P = 0.179). Also, its effect on FEV1 (SMD: - 0.06, 95% CI: - 0.30 to 0.17) and FEV1/FVC (SMD: -0.10, 95% CI: - 0.48 to 0.27) remained negligible. However, it could increase the serum 25(OH)D concentration (SMD: 2.44, 95 CI%: 2.20 to 2.68, P < 0.001).

Conclusions

The effects of vitamin D supplementation on decreasing exacerbation and improving pulmonary function were not significant.

The role of vitamin D in chronic obstructive pulmonary disease with pulmonary hypertension

Hypoxia pulmonary hypertension (PH) belongs to the third major category in PH classification. Chronic obstructive pulmonary disease (COPD) is a common cause of hypoxia PH. Low serum vitamin D concentration is considered to be a possible risk factor for chronic lung disease; epidemiological studies have found that vitamin D deficiency increases pulmonary artery pressure. Therefore, this study aimed to explore the role of vitamin D levels in COPD and chronic hypoxic PH. This retrospective study selected three groups of people as research subjects, including: Group N: normal control group (people without any chronic lung disease or PH); Group C: patients with COPD, but without PH; Group C + PH: patients with COPD and PH. Vitamin D levels and pulmonary artery pressure were observed in the three groups. Vitamin D levels of the three groups showed statistical differences in every pairwise comparison; the vitamin D level of Group C (20.27 ng/mL) was lower than Group N (23.48 ng/mL), Group C + PH was the lowest (14.92 ng/mL). The levels of vitamin D in the three groups in this study were generally low. Vitamin D is negatively correlated with pulmonary artery systolic blood pressure. Low vitamin D levels may have a certain relationship with the occurrence and development of COPD. Further reductions in vitamin D levels may influence the development of PH in COPD.

Calcifediol in the management of vitamin D deficiency-related skeletal and extraskeletal diseases: overview and clinical cases

As well as being essential for musculoskeletal health, vitamin D is involved in numerous other physiological processes. Poor vitamin D status is linked to a wide range of diseases, including cardiovascular disease, autoimmune conditions, pulmonary disorders and upper respiratory tract infections. While optimal target concentrations of serum 25-hydroxyvitamin D (25(OH)D) for health maintenance or therapeutic purposes are still the subject of debate, there is reasonable agreement that serum 25(OH)D levels <50 nmol/L (20 ng/mL) constitute vitamin D deficiency and that severe deficiency states (serum 25(OH)D levels <25-30 nmol/L ≈ 10-12 ng/mL) should be avoided. Main strategies to maintain or improve vitamin D status are food supplementation and therapeutic use of medicinal forms of vitamin D. In this review, we examine evidence that implicates vitamin D deficiency in diverse conditions in the clinical settings of endocrinology, rheumatology, pneumology and reproductive health. Cholecalciferol (vitamin D3) is the most frequently used vitamin D supplement worldwide, though calcifediol (25-hydroxyvitamin D3) has recently become more widely available. Calcifediol is one step closer than cholecalciferol in the metabolic pathway to biologically active vitamin D. Pharmacokinetic differences between these vitamin D metabolites confer putative advantages for calcifediol in certain clinical situations. The clinical use of calcifediol is explored more closely through case studies, which illustrate its adjunctive role in the treatment of several vitamin D deficiency-related skeletal and extraskeletal diseases.

The effects of vitamin D on all-cause mortality in different diseases: an evidence-map and umbrella review of 116 randomized controlled trials

Purpose

To conduct a solid evidence by synthesizing meta-analyses and updated RCTs about the effects of vitamin D on all-cause mortality in different health conditions.

Methods

Data sources: Pubmed, Embase, Web of Science, the Cochrane Library, Google Scholar from inception until 25th April, 2022. Study selection: English-language, meta-analyses and updated RCTs assessing the relationships between vitamin D and all-cause mortality. Data synthesis: Information of study characteristics, mortality, supplementation were extracted, estimating with fixed-effects model. A Measurement Tool to Assess Systematic Reviews, Grading of Recommendations Assessment, Development and Evaluation, and funnel plot was used to assess risk of bias. Main outcomes: All-cause mortality, cancer mortality, cardiovascular disease mortality.

Results

In total of 27 meta-analyses and 19 updated RCTs were selected, with a total of 116 RCTs and 149, 865 participants. Evidence confirms that vitamin D reduces respiratory cancer mortality (RR, 0.56 [95%CI, 0.33 to 0.96]). All-cause mortality is decreased in patients with COVID-19 (RR, 0.54[95%CI, 0.33 to 0.88]) and liver diseases (RR, 0.64 [95%CI, 0.50 to 0.81]), especially in liver cirrhosis (RR, 0.63 [95%CI, 0.50 to 0.81]). As for other health conditions, such as the general health, chronic kidney disease, critical illness, cardiovascular diseases, musculoskeletal diseases, sepsis, type 2 diabetes, no significant association was found between vitamin D and all-cause mortality.

Conclusions

Vitamin D may reduce respiratory cancer mortality in respiratory cancer patients and all-cause mortality in COVID-19 and liver disorders' patients. No benefits showed in all-cause mortality after vitamin D intervention among other health conditions. The hypothesis of reduced mortality with vitamin D still requires exploration.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=252921, identifier: CRD42021252921.

Vitamin D status and chronic obstructive pulmonary disease risk: a prospective UK Biobank study

BACKGROUND

Low vitamin D status has been linked to an increased risk for various inflammatory diseases. Conflicting results have been reported regarding chronic obstructive pulmonary disease (COPD). This study aims to investigate the associations of serum 25-hydroxyvitamin D (25(OH)D) concentrations with COPD risk and survival.

METHODS

We included 403 648 participants with serum 25(OH)D measurements and free of COPD at baseline from UK Biobank. Follow-up was until 30 September 2021. Multivariable-adjusted cox regression models were applied to estimate HRs and 95% CIs for the associations of season-standardised 25(OH)D concentrations with COPD risk and survival. The restricted cubic splines were used to assess dose-response relationship. Kaplan-Meier estimation was used to create graphs of the survival curves.

RESULTS

During a median follow-up of 12.3 (IQR: 11.4-13.2) years, 11 008 cases of COPD were recorded. We observed a non-linear inverse association between 25(OH)D concentrations and COPD risk. Compared with participants in the fourth quintile of 25(OH)D, those in the lowest quintile were associated with a 23% higher risk (HR, 1.23; 95% CI, 1.16 to 1.31). Stronger associations were observed for the risk in men and current smokers (Both p for interaction <0.05). In survival analyses, compared with the fourth quintile, cases in the lowest quintile had a 38% higher risk for overall death (HR, 1.38; 95% CI, 1.22 to 1.56).

CONCLUSION

Our findings indicate that serum 25(OH)D concentrations are non-linearly negatively associated with incidence and mortality of COPD, suggesting a potential protective role of vitamin D in the pathogenesis of COPD.

Prevention of COVID-19 with oral vitamin D supplemental therapy in essential healthcare teams (PROTECT): protocol for a multicentre, triple-blind, randomised, placebo-controlled trial

INTRODUCTION

In the COVID-19 pandemic, healthcare workers (HCWs) were at high risk of infection due to their exposure to COVID infections. HCWs were the backbone of our healthcare response to this pandemic; every HCW withdrawn or lost due to infection had a substantial impact on our capacity to deliver care. Primary prevention was a key approach to reduce infection. Vitamin D insufficiency is highly prevalent in Canadians and worldwide. Vitamin D supplementation has been shown to significantly decrease the risk of respiratory infections. Whether this risk reduction would apply to COVID-19 infections remained to be determined. This study aimed to determine the impact of high-dose vitamin D supplementation on incidence of laboratory-confirmed COVID-19 infection rate and severity in HCWs working in high COVID incidence areas.

METHODS AND ANALYSIS

PROTECT was a triple-blind, placebo-controlled, parallel-group multicentre trial of vitamin D supplementation in HCWs. Participants were randomly allocated in a 1:1 ratio in variable block size to intervention (one oral loading dose of 100 000 IU vitamin D₃+10 000 IU weekly vitamin D₃) or control (identical placebo loading dose+weekly placebo). The primary outcome was the incidence of laboratory-confirmed COVID-19 infection, documented by RT-qPCR on salivary (or nasopharyngeal) specimens obtained for screening or diagnostic purposes, as well as self-obtained salivary specimens and COVID-19 seroconversion at endpoint. Secondary outcomes included disease severity; duration of COVID-19-related symptoms; COVID-19 seroconversion documented at endpoint; duration of work absenteeism; duration of unemployment support; and adverse health events. The trial was terminated prematurely, due to recruitment difficulty.

ETHICS AND DISSEMINATION

This study involves human participants and was approved by the Research Ethics Board (REB) of the Centre hospitalier universitaire (CHU) Sainte-Justine serving as central committee for participating institutions (#MP-21-2021-3044). Participants provided written informed consent to participate in the study before taking part. Results are being disseminated to the medical community via national/international conferences and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

https://clinicaltrials.gov/ct2/show/NCT04483635.

A Scoping Review of Vitamin D for Nonskeletal Health: A Framework for Evidence-based Clinical Practice

BACKGROUND

Low serum 25-hydroxy-vitamin D [25(OH)D] levels are prevalent worldwide. Although the benefits of vitamin D supplementation have focused on skeletal disorders (eg, rickets, osteomalacia, osteoporosis), emerging evidence for nonskeletal health merits further discussion.

PURPOSE

The purpose of this review was to critically examine the vitamin D supplementation literature pertaining to nonskeletal health to help guide clinicians.

METHODS

A scoping review that included observational studies and randomized clinical trials (RCTs) was performed. Evidence from meta-analyses and individual RCTs are discussed, and controversies and future directions are considered.

FINDINGS

25(OH)D deficiency is a ubiquitous condition associated with multiple nonskeletal diseases, including cardiometabolic (heart disease, diabetes, and kidney disease), immune (HIV/AIDS and cancer), lung (from traditional chronic disorders to coronavirus disease 2019), and gut diseases. Vitamin D deficiency also affects health across the life span (children, pregnant, and elderly), mental illness, and reproduction in both men and women. In contrast, vitamin D supplementation does not necessarily improve major medical outcomes, even when low 25(OH)D levels are treated. Screening for 25(OH)D status remains an important practice, primarily for high-risk patients (eg, elderly, women with osteoporosis, people with low exposure to sunlight). It is reasonable to supplement with vitamin D to treat 25(OH)D deficiency, such that if beneficial nonskeletal health occurs, this may be considered as a coadjutant instead of the central tenet of the disease. Furthermore, optimizing dosing regimens is an important clinical consideration.

IMPLICATIONS

Although 25(OH)D deficiency is prevalent in nonskeletal diseases, there is no uniform evidence that vitamin D supplementation improves major medical outcomes, even when low 25(OH)D levels are corrected. Findings from RCTs warrant caution due to possible selection bias. Overall, vitamin D supplementation must be guided by circulating levels as a reasonable medical practice to correct 25(OH)D deficiency.

Alveolar-Capillary Barrier Protection In Vitro: Lung Cell Type-Specific Effects and Molecular Mechanisms Induced by 1α, 25-Dihydroxyvitamin D3

Low serum levels of 1α, 25-dihydroxyvitamin D3 (VD3) are associated with a higher mortality in trauma patients with sepsis or ARDS. However, the molecular mechanisms behind this observation are not yet understood. VD₃ is known to stimulate lung maturity, alveolar type II cell differentiation, or pulmonary surfactant synthesis and guides epithelial defense during infection. In this study, we investigated the impact of VD₃ on the alveolar-capillary barrier in a co-culture model of alveolar epithelial cells and microvascular endothelial cells respectively in the individual cell types. After stimulation with bacterial LPS (lipopolysaccharide), gene expression of inflammatory cytokines, surfactant proteins, transport proteins, antimicrobial peptide, and doublecortin-like kinase 1 (DCLK1) were analyzed by real-time PCR, while corresponding proteins were evaluated by ELISA, immune-fluorescence, or Western blot. The effect of VD3 on the intracellular protein composition in H441 cells was analyzed by quantitative liquid chromatography-mass spectrometry-based proteomics. VD₃ effectively protected the alveolar-capillary barrier against LPS treatment, as indicated by TEER measurement and morphological assessment. VD₃ did not inhibit the IL-6 secretion by H441 and OEC but restricted the diffusion of IL-6 to the epithelial compartment. Further, VD₃ could significantly suppress the surfactant protein A expression induced in the co-culture system by LPS treatment. VD₃ induced high levels of the antimicrobial peptide LL-37, which counteracted effects by LPS and strengthened the barrier. Quantitative proteomics identified VD3-dependent protein abundance changes ranging from constitutional extracellular matrix components and surfactant-associated proteins to immune-regulatory molecules. DCLK1, as a newly described target molecule for VD₃, was prominently stimulated by VD₃ (10 nM) and seems to influence the alveolar-epithelial cell barrier and regeneration.

Vitamin D Supplementation and Its Impact on Mortality and Cardiovascular Outcomes: Systematic Review and Meta-Analysis of 80 Randomized Clinical Trials

BACKGROUND

The impact of vitamin D supplementation on cardiovascular outcomes and mortality risk reduction remains unclear due to conflicting study findings.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), published between 1983 and 2022, that reported the effect of vitamin D supplementation in adults versus placebo or no treatment on all-cause mortality (ACM), cardiovascular mortality (CVM), non-cardiovascular mortality (non-CVM), and cardiovascular morbidities. Only studies with a follow-up period longer than one year were included. The primary outcomes were ACM and CVM. Secondary outcomes were non-CVM, myocardial infarction, stroke, heart failure, and major or extended adverse cardiovascular events. Subgroup analyses were performed according to low-, fair- and good-quality RCTs.

RESULTS

Eighty RCTs were assessed, including 82,210 participants receiving vitamin D supplementation and 80,921 receiving placebo or no treatment. The participants' mean (SD) age was 66.1 (11.2) years, and 68.6% were female. Vitamin D supplementation was associated with a lower risk of ACM (OR: 0.95 [95%CI 0.91-0.99] p = 0.013), was close to statistical significance for a lower risk of non-CVM (OR: 0.94 [95%CI 0.87-1.00] p = 0.055), and was not statistically associated with a lower risk of any cardiovascular morbi-mortality outcome. Meta-analysis of low-quality RCTs showed no association with cardiovascular or non-cardiovascular morbi-mortality outcomes.

CONCLUSIONS

The emerging results of our meta-analysis present evidence that vitamin D supplementation appears to decrease the risk of ACM (especially convincing in the fair- and good-quality RCTs), while not showing a decrease in the specific cardiovascular morbidity and mortality risk. Thus, we conclude that further research is warranted in this area, with well-planned and executed studies as the basis for more robust recommendations.

The interplay between hypovitaminosis D and the immune dysfunction in the arteriovenous thrombotic complications of the sever coronavirus disease 2019 (COVID-19) infection

Thromboembolic complications including cerebrovascular accidents, pulmonary embolism, myocardial infarction, deep vein thrombosis and disseminating intravascular coagulopathy are serious encounters in sever coronavirus disease 2019 (COVID-19) infected patients. This worsens the prognosis and may lead to death or life long morbidities. The laboratory finding of the disturbed haemostasias and the hyperinflammatory response are almost invariably present in COVID-19 patients. Multiple treatment modalities are utilized by the healthcare professionals to overcome the cytokine storm, oxidative stress, endothelial dysfunction, and coagulopathy in these patients. The combined actions of vitamin D (VitD) as a steroid hormone with anti-inflammatory, immunomodulatory, and antithrombotic properties increase the potential of the possible involvement of hypovitaminosis D in the thromboembolic complications of COVID-19 infection, and stimulated researchers and physicians to administer VitD therapy to prevent the infection and/or overcome the disease complications. The current review highlighted the immunomodulatory, anti-inflammatory, antioxidative and hemostatic functions of VitD and its interrelation with the renin-angiotensin-aldosterone system (RAAS) pathway and the complement system. Additionally, the association of VitD deficiency with the incidence and progression of COVID-19 infection and the associated cytokine storm, oxidative stress, hypercoagulability, and endothelial dysfunction were emphasized. Normalizing VitD levels by daily low dose therapy in patients with hypovitaminosis D below (25 nmol/l) is essential for a balanced immune response and maintaining the health of the pulmonary epithelium. It protects against upper respiratory tract infections and decreases the complications of COVID-19 infections. Understanding the role of VitD and its associated molecules in the protection against the coagulopathy, vasculopathy, inflammation, oxidative stress and endothelial dysfunction in COVID-19 infection could lead to new therapeutic strategies to prevent, treat, and limit the complications of this deadly virus infection.

An inverse causal association between genetically predicted vitamin D and chronic obstructive pulmonary disease risk

Aim

Observational studies have reported that levels of vitamin D were associated with the incidence of chronic obstructive pulmonary disease (COPD), but the relationship between them may have been confounded in previous studies. In this study, we aimed to determine the relationship between the levels of 25-hydroxyvitamin D (25OHD) and the risk of COPD by two-sample Mendelian randomization (MR) analysis.

Methods

Summary statistics for 25OHD and COPD in this study were obtained from the EBI (n = 496,946) consortium and Finn (n = 187,754) consortium. MR was adopted to explore the effect of the genetically predicted levels of 25OHD on the risk of COPD. Based on three assumptions of MR analysis, inverse variance weighting was used as the main analysis. To make our results more robust and reliable, MR Egger’s intercept test, Cochran’s Q test, funnel plot, and “leave-one-out” sensitivity analysis were used to assess the potential pleiotropy and heterogeneity in this study. Then, colocalization analysis and MR Steiger approaches were used to estimate the possible directions of estimates between them. Finally, we analyzed the causal associations between the four core genes (DHCR7, GC, CYP2R1, and CYP24A1) of vitamin D and the levels of 25OHD or the risk of COPD.

Results

Our results showed that each 1 standard deviation (SD) increase in the genetically predicted 25OHD level was associated with a 57.2% lower relative risk of COPD [odds ratio (OR): 0.428, 95% Cl: 0.279–0.657, p = 1.041 × 10−4], and the above association was also verified by maximum likelihood (OR: 0.427, 95% Cl: 0.277–0.657, p = 1.084 × 10−4), MR–Egger (OR: 0.271, 95% CI: 0.176–0.416, p = 2.466 × 10−4), MR-PRESSO (OR: 0.428, 95% Cl: 0.281–0.652, p = 1.421 × 10−4) and MR-RAPS (OR: 0.457, 95% Cl: 0.293–0.712, p = 5.450 × 10−4). Furthermore, colocalization analyses (rs3829251, PP.H4 = 0.99) and MR Steiger (“TRUE”) also showed a reverse association between them. Besides, the core genes of vitamin D also showed similar results except for CYP24A1.

Conclusion

Our findings provide evidence for a reverse association between genetically predicted 25OHD levels and COPD risk. Taking measures to supplement 25OHD may help reduce the incidence of COPD.

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.

Protective Effect of Vitamin D Supplementation on COVID-19-Related Intensive Care Hospitalization and Mortality: Definitive Evidence from Meta-Analysis and Trial Sequential Analysis

BACKGROUND

The COVID-19 pandemic represents one of the world's most important challenges for global public healthcare. Various studies have found an association between severe vitamin D deficiency and COVID-19-related outcomes. Vitamin D plays a crucial role in immune function and inflammation. Recent data have suggested a protective role of vitamin D in COVID-19-related health outcomes. The purpose of this meta-analysis and trial sequential analysis (TSA) was to better explain the strength of the association between the protective role of vitamin D supplementation and the risk of mortality and admission to intensive care units (ICUs) in patients with COVID-19.

METHODS

We searched four databases on 20 September 2022. Two reviewers screened the randomized clinical trials (RCTs) and assessed the risk of bias, independently and in duplicate. The pre-specified outcomes of interest were mortality and ICU admission.

RESULTS

We identified 78 bibliographic citations. After the reviewers' screening, only five RCTs were found to be suitable for our analysis. We performed meta-analyses and then TSAs. Vitamin D administration results in a decreased risk of death and ICU admission (standardized mean difference (95% CI): 0.49 (0.34-0.72) and 0.28 (0.20-0.39), respectively). The TSA of the protective role of vitamin D and ICU admission showed that, since the pooling of the studies reached a definite sample size, the positive association is conclusive. The TSA of the protective role of vitamin D in mortality risk showed that the z-curve was inside the alpha boundaries, indicating that the positive results need further studies.

DISCUSSION

The results of the meta-analyses and respective TSAs suggest a definitive association between the protective role of vitamin D and ICU hospitalization.

Efficacy of vitamin D supplementation on COPD and asthma control: A systematic review and meta-analysis

Background

The role of vitamin D (VD) in the management of chronic obstructive pulmonary disease (COPD) and asthma remains largely undetermined. In the present meta-analysis, we aimed to comprehensively investigate the efficacy of VD in the treatment of COPD and asthma according to the latest update.

Methods

The PubMed, Embase, and Cochrane Library databases were searched from their inception to June 2, 2022. Randomized controlled trials (RCTs) comparing the efficacy of VD with placebo against COPD or asthma were included.

Results

A total of 11 RCTs consisting of 1183 COPD patients and 19 RCTs consisting of 2025 asthmatic patients were finally included. As for pulmonary function, FEV1/FVC was not changed significantly, while FEV1% was improved in the VD group. In the asthma subgroup, FEV1% was not changed significantly, while FEV1/FVC was improved in the VD group. For the questionnaire and rating scale, the mMRC (modified Medical Research Council) dyspnoea scale score for COPD and ACT (Asthma Control Test) score for asthma were not significantly changed, while the SGRQ (St. George's Respiratory Questionnaire) score for COPD was improved in the VD group. For inflammation indicators, IL-6 and IL-10 were statistically equivalent between the VD and placebo groups, while IgE, IL-5, and IL-10 (baseline VD deficiency subgroup) were improved in the VD group. The exacerbation, length of hospital stays, and mortality were statistically equivalent between the two groups.

Conclusions

VD supplementation improved the indicators of asthma and COPD, especially in pulmonary function, SGRQ scores, IL-5, and IgE.

Registration

The protocol could be found at PROSPERO with the registration number of CRD42020218058.

Vitamin D Levels in Patients with Overlap Syndrome, Is It Associated with Disease Severity?

Background: The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) has been defined as overlap syndrome (OVS). Recently, a link between OSA, COPD and Vitamin D (Vit D) serum concentration was reported, however, evidence regarding Vit D status in patients with OVS is scarce. The aim of the present study was to evaluate Vit D serum levels and to explore the association of those levels with anthropometric, pulmonary function and sleep parameters in patients with OVS. Methods: Vit D serum levels were measured in patients diagnosed with OVS, as confirmed by overnight polysomnography and pulmonary function testing. Results: A total of 90 patients (79 males and 11 females) were included in the analysis. The patients were divided into three groups matched for age, gender, and BMI: the control group that included 30 patients (27 males and 3 females), the OSA group that included 30 patients (26 males and 4 females), and the OVS group that included 30 patients (26 males and 4 females). Patients with OVS exhibited decreased serum 25(OH)D levels compared with OSA patients and controls (14.5 vs. 18.6 vs. 21.6 ng/mL, p < 0.001). In the OVS group, multiple linear regression analysis identified AHI and FEV1, as predictors of serum 25(OH)D levels (p = 0.041 and p = 0.038, respectively). Conclusions: Lower Vit D levels have been observed in patients with OVS compared with OSA patients and non-apneic controls, indicating an increased risk of hypovitaminosis D in this population which might be associated with disease severity.

Recent advances in vitamin D implications in chronic respiratory diseases

Chronic airway inflammatory and infectious respiratory diseases are the most common medical respiratory conditions, associated with significant morbidity and mortality. Vitamin D (1,25(OH)₂D₃) deficiency has been shown to be highly prevalent in patients with chronic airway inflammatory and infectious diseases, correlated with increased disease severity. It has been established that vitamin D modulates ongoing abnormal immune responses in chronic respiratory diseases and is shown to restrict bacterial and viral colonization into the lungs. On the contrary, other studies revealed controversy findings regarding vitamin D efficacy in respiratory diseases. This review aims to update the current evidence regarding the role of vitamin D in airway inflammation and in various respiratory diseases. A comprehensive search of the last five years of literature was conducted using MEDLINE and non-MEDLINE PubMed databases, Ovid MEDLINE, SCOPUS-Elsevier, and data from in vitro and in vivo experiments, including clinical studies. This review highlights the importance of understanding the full range of implications that vitamin D may have on lung inflammation, infection, and disease severity in the context of chronic respiratory diseases.

Association between Vitamin D Supplementation and Cancer Mortality: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D deficiency is related to increased cancer risk and deaths. However, whether vitamin D supplementation reduces cancer mortality remains unclear, and several randomized controlled trials yield inconsistent results.

METHODS

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from their inception until 28 June 2022, for randomized controlled trials investigating vitamin D supplementation. Pooled relative risks (RRs) and their 95% confidence intervals (CIs) were estimated. Trials with vitamin D supplementation combined with calcium supplementation versus placebo alone and recruiting participants with cancer at baseline were excluded in the present study.

RESULTS

This study included 12 trials with a total of 72,669 participants. Vitamin D supplementation did not reduce overall cancer mortality (RR 0.96, 95% CI 0.80-1.16). However, vitamin D supplementation was associated with a reduction in lung cancer mortality (RR 0.63, 95% CI 0.45-0.90).

CONCLUSIONS

Vitamin D supplementation could not reduce cancer mortality in this highly purified meta-analysis. Further RCTs that evaluate the association between vitamin D supplementation and total cancer mortality are still needed.

The Dietary Inflammatory Index and Early COPD: Results from the National Health and Nutrition Examination Survey

We examined 3962 people aged 20 to 49 years who had information on spirometry testing and underwent a 24 h dietary recall interview from the 2007-2012 National Health and Nutrition Examination Survey (NHANES) and used multivariable logistic regression to evaluate associations between Dietary Inflammatory Index (DII, a pro-inflammatory diet) and early COPD and lung function. The overall prevalence of early COPD was 5.05%. Higher DII was associated with increased odds of early COPD (quartile 4 vs. 1, the OR = 1.657, 95% CI = 1.100-2.496, p = 0.0156). In a full-adjusted model, each unit of increase in DII score was associated with a 90.3% increase in the risk of early COPD. Higher DII is significantly associated with lower FEV1 and FVC among individuals with early COPD, each unit increment in the DII was significantly associated with 0.43 L-0.58 L decrements in FEV1 (β = -0.43, 95% CI = -0.74, -0.12) and FVC (β = -0.58, 95% CI = -1.01, -0.16). These findings demonstrate that higher consumption of a pro-inflammatory diet may contribute to an increased risk of early COPD and lower lung function, and further support dietary interventions as part of a healthy lifestyle in order to preserve lung function and prevent or improve COPD.

Vitamin D supplementation in chronic obstructive pulmonary disease patients with low serum vitamin D: a randomized controlled trial

BACKGROUND

Vitamin D deficiency is frequently found in patients with chronic obstructive pulmonary disease (COPD). Vitamin D has antimicrobial, anti-inflammatory, and immunomodulatory effects. Therefore, supplementation may prevent COPD exacerbations, particularly in deficient patients.

OBJECTIVES

We aimed to assess the effect of vitamin D supplementation on exacerbation rate in vitamin D-deficient patients with COPD.

METHODS

We performed a multicenter, double-blind, randomized controlled trial. COPD patients with ≥1 exacerbations in the preceding year and a vitamin D deficiency (15-50 nmol/L) were randomly allocated in a 1:1 ratio to receive either 16,800 International Units (IU) vitamin D3 or placebo once a week during 1 y. Primary outcome of the study was exacerbation rate. Secondary outcomes included time to first and second exacerbations, time to first and second hospitalizations, use of antibiotics and corticosteroids, pulmonary function, maximal respiratory mouth pressure, physical performance, skeletal muscle strength, systemic inflammatory markers, nasal microbiota composition, and quality of life.

RESULTS

The intention-to-treat population consisted of 155 participants. Mean ± SD serum 25-hydroxyvitamin D [25(OH)D] concentration after 1 y was 112 ± 34 nmol/L in the vitamin D group, compared with 42 ± 17 nmol/L in the placebo group. Vitamin D supplementation did not affect exacerbation rate [incidence rate ratio (IRR): 0.90; 95% CI: 0.67, 1.21]. In a prespecified subgroup analysis in participants with 25(OH)D concentrations of 15-25 nmol/L (n = 31), no effect of vitamin D supplementation was found (IRR: 0.91; 95% CI: 0.43, 1.93). No relevant differences were found between the intervention and placebo groups in terms of secondary outcomes.

CONCLUSIONS

Vitamin D supplementation did not reduce exacerbation rate in COPD patients with a vitamin D deficiency.This trial was registered at clinicaltrials.gov as NCT02122627.

Association between vitamin D supplementation and cancer incidence and mortality: A trial sequential meta-analysis of randomized controlled trials

Observational studies and clinical trials have evaluated the associations between vitamin D supplementation and cancer incidence/mortality and obtained mixed results. Previous meta-analyses have also yielded inconsistent conclusions. In this paper, we conduct an updated meta-analysis by including current randomized clinical trials (RCTs) to assess the association between vitamin D supplementation and cancer incidence and mortality. The PubMed, Scopus and Embase databases were systematically searched from their inception to 6 February 2022. Fixed-effects meta-analyses were conducted. Trial sequential analyses were performed using a risk ratio reduction threshold of 10% for cancer incidence and mortality. Twenty-six RCTs were eligible, and pooled results indicated that vitamin D supplementation, compared to placebo with/without calcium, was not associated with a reduction in total cancer incidence (risk ratio: 0.98, 95% CI: 0.94, 1.02; I2 = 0%). In contrast, vitamin D supplementation significantly reduced total cancer mortality (risk ratio: 0.88, 95% CI: 0.8, 0.96; I2 = 0%). Moreover, trial sequential analysis provided reliable evidence that supplementation with vitamin D lowered the relative risk of total cancer mortality by 10%. Our updated meta-analysis suggested that vitamin D supplementation did not reduce total cancer incidence but significantly lowered total cancer mortality.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2056574 .

Vitamin D3 alleviates cigarette smoke extract‑mediated epithelial‑mesenchymal transition and fibrogenesis by upregulating CC16 expression in bronchial epithelial cells

Vitamin D3 supplementation has been previously reported to inhibit the occurrence and development of chronic obstructive pulmonary disease (COPD). However, the underlying mechanism remains unclear. Epithelial-mesenchymal transition (EMT) and fibrogenesis have been associated with the development of COPD. The aim of the present study was to investigate the potential effects and mechanism of vitamin D3 in an in vitro model of cigarette smoke (CS)-induced EMT and fibrosis, with specific focus on the role of club cell protein 16 (CC16). CS extract (CSE) at different concentrations (5, 10 and 20%) was used to treat 16-HBE cells to induce EMT and fibrogenesis following which they were treated with vitamin D3. Subsequently, the 20% CSE group was selected for further experiments, where 16-HBE cells were divided into the following five groups: The control group; the CSE group; the low-dose vitamin D3 group (250 nM); the medium-dose vitamin D3 group (500 nM); and the high-dose vitamin D3 group (1,000 nM). Western blot analysis was used to detect the protein expression levels of the EMT-related proteins E-cadherin, N-cadherin, Slug and α-SMA, fibrogenesis-related proteins collagen Ⅳ and fibronectin 1, proteins involved in the TGF-β1/SMAD3 signaling pathway and CC16. Immunofluorescence was used to measure the protein expression levels of E-cadherin, N-cadherin and collagen Ⅳ. Specific CC16 knockdown was performed using short hairpin RNA transfection to investigate the role of CC16. The results of the present study found that vitamin D3 could increase the protein expression level of CC16 to inhibit the activation of the TGF-β1/SMAD3 signaling pathway; thereby reducing the 20% increase in CSE-induced EMT- and fibrogenesis-related protein expression levels. Following CC16 knockdown, the inhibitory effects of vitamin D3 on EMT- and fibrogenesis-related protein expression were partially reversed. To conclude, these results suggest that vitamin D3 can inhibit the protein expression levels of EMT- and fibrogenesis-related proteins induced by CSE, at least partially through the function of CC16. These findings are expected to provide novel theoretical foundations and ideas for the pathogenesis and treatment of COPD.

Vitamin D Receptor Influences Intestinal Barriers in Health and Disease

Vitamin D receptor (VDR) executes most of the biological functions of vitamin D. Beyond this, VDR is a transcriptional factor regulating the expression levels of many target genes, such as genes for tight junction proteins claudin-2, -5, -12, and -15. In this review, we discuss the progress of research on VDR that influences intestinal barriers in health and disease. We searched PubMed and Google Scholar using key words vitamin D, VDR, tight junctions, cancer, inflammation, and infection. We summarize the literature and progress reports on VDR regulation of tight junction distribution, cellular functions, and mechanisms (directly or indirectly). We review the impacts of VDR on barriers in various diseases, e.g., colon cancer, infection, inflammatory bowel disease, and chronic inflammatory lung diseases. We also discuss the limits of current studies and future directions. Deeper understanding of the mechanisms by which the VDR signaling regulates intestinal barrier functions allow us to develop efficient and effective therapeutic strategies based on levels of tight junction proteins and vitamin D/VDR statuses for human diseases.

Associations of Vitamin D, chronic obstructive pulmonary disease and acute exacerbations of COPD with anxiety and depression: a nested case control study

Background: Lower vitamin D levels have not only been associated with chronic obstructive pulmonary disease (COPD), exacerbations and lower lung functions, but also with anxiety and depression. We examined the associations of severity of anxiety and depression using HAM-A (Hamilton Anxiety Rating Scale) and HAM-D (Hamilton Depression Rating Scale) scores with COPD and vitamin D levels. Methods: Observational nested case control study was conducted in MUDHRA cohort. One hundred COPD subjects and 100 age- gender- matched non-COPD subjects (controls) underwent evaluation of socioeconomic status, respiratory symptoms, spirometry, severity of anxiety and depression, six minute walk test and estimation of serum vitamin D levels. Independent association of low vitamin D levels with severity of anxiety and depression was assessed by logistic regression. Results: COPD group had higher mean±SD anxiety and depression scores (HAM-A 8.0±3.5, HAM-D 8.72±4) compared to control group (HAM-A 4.51±2.2, HAM-D 4.3±2). The COPD group had 53 subjects with mild/moderate anxiety/depression whereas control group had 16 subjects with mild/moderate anxiety/depression. In COPD group, subjects with mild/moderate anxiety/depression had lower vitamin D levels compared to subjects with no/minimal anxiety/depression, while the difference in control group was not significant. In logistic regression, anxiety and depression levels had independent association with vitamin D levels, lung function variables, six-minute walk distance and presence of COPD. In COPD subgroup, anxiety and depression levels had independent association with breathlessness, GOLD FEV1 staging, CAT score, SGRQ-C Symptom score and exacerbation of COPD. Conclusions: Greater proportion of COPD subjects suffer from anxiety and depression as compared to subjects without COPD. Severity of anxiety and depression was greater in COPD subjects. Poorer lung functions, higher respiratory symptoms and lower vitamin D levels are associated with higher levels of anxiety and depression in COPD subjects.  There is an urgent need to recognise anxiety and depression in COPD patients.

Testing for Vitamin D in High-Risk COPD in Outpatient Clinics in Spain: A Cross-Sectional Analysis of the VITADEPOC Study

Background: Vitamin D deficiency has been associated with an accelerated deterioration in lung function and increased exacerbations in chronic obstructive pulmonary disease (COPD). 25(OH) vitamin D levels have been indicated as a potentially useful marker for adverse results related to COPD. Methods: VITADEPOC is a cross-sectional clinical study recruiting consecutive patients with high-risk COPD. The objective of our study was to investigate vitamin D determination frequency in patients with high-risk COPD in clinical practice at outpatient clinics in Spain and to describe the factors associated with vitamin D testing. We also aimed to determine the frequency of vitamin D deficiency in these patients. Results: Only 51 (44%) patients underwent vitamin D determination and 33 (28.4%) had received vitamin D supplements in clinical practice. The patients who underwent testing for vitamin D in clinical practice were more often women (58.8% vs. 26.2%, p < 0.001) with comorbidities such as osteoporosis (19.6% vs. 6.2%, p < 0.001) or chronic renal failure (7.8% vs. 0%, p < 0.001) and with exacerbator phenotype (55% vs. 32.3%, p = 0.015). A total of 63 (54.3%) patients had serum vitamin D levels <20 ng/mL at the inclusion visit. Of these, 29 (46%) had serum vitamin D levels <12 ng/mL (severe deficiency). Having a history of inhaled corticosteroids (OR 3.210, p < 0.016), being treated with a cycle of systemic corticosteroids (OR 2.149, p < 0.002), and having a lower physical activity level (OR 3.840, p < 0.004) showed a statistically significant positive association with vitamin D deficiency. Conclusion: The testing of vitamin D levels in patients with high-risk COPD treated at outpatient respiratory clinics in Spain is infrequent. However, when tested, a severe deficiency is detected in one in four patients. Efforts to optimize case detection in COPD are needed.

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.

Vitamin D, respiratory infections, and chronic disease: Review of meta-analyses and randomized clinical trials

BACKGROUND

Observational studies have suggested associations of vitamin D deficiency (VDD) with respiratory tract infections, impaired bone health, and myriad chronic diseases.

OBJECTIVE

To assess potential causal relationships between vitamin D supplementation and a reduced risk of these conditions, a review of the evidence across available meta-analyses of randomized control trials (RCTs) and RCTs was performed.

METHOD

PubMed, Embase, Cochrane Library, and Web of Science were searched from their inception to March 2021. We included only RCTs and meta-analyses of RCTs focusing on the association between vitamin D and respiratory disease, bone health, cardiovascular disease (CVD), diabetes mellitus, and cancer.

RESULTS

A total of 107 RCTs and 62 meta-analysis of RCTs were included. Although most RCTs did not support benefits of vitamin D supplementation, suggestive evidence for benefit was found in populations at greater risk of VDD and for acute respiratory infections, fractures in institutionalized older adults, type 2 diabetes among patients with prediabetes, and cancer mortality. In contrast, no compelling evidence for benefit was found for other respiratory conditions, fractures in community-dwelling adults, falls, cancer incidence, or CVD.

CONCLUSIONS

Current evidence from RCTs and meta-analyses of RCTs is inconsistent regarding the effects of vitamin D supplementation on respiratory infections and chronic diseases. Individuals most likely to benefit are those with baseline VDD or with selected high-risk conditions. Public health initiatives are needed to eliminate VDD globally, and future research will be enhanced by a 'precision prevention' approach to identify those most likely to benefit from vitamin D supplementation.

A review on the Role of Oral Nutritional Supplements in Chronic Obstructive Pulmonary Disease

Due to the high smoking rate in developing countries and the rising aging population in high-income countries, the global prevalence of chronic obstructive pulmonary disease (COPD), estimated to be 11.7%, is increasing and is the third-leading cause of mortality. COPD is likely to be present in elderly individuals with impaired gastro-enteric functions. Gastrointestinal congestion, dyspnea, and anxiety are pathophysiological characteristics of COPD, contributing to poor appetite, reduced dietary intake, and high-energy expenditure. These factors are implicated in the progression of malnutrition in COPD patients. Malnutrition is detrimental to lung functions and is associated with an increased risk of infection, exacerbation and mortality, and a longer duration of hospitalization. Therefore, nutritional support to treat malnutrition in COPD patients is very vital. Oral nutritional supplements (ONS) may hold the key to COPD treatment. To clarify this statement, we review current evidence for ONS in COPD patients to benefit from clinical outcomes.

Effect of Antioxidants in the Treatment of COPD Patients: Scoping Review

Chronic obstructive pulmonary disease (COPD) is a common, preventable, treatable lung disease characterized by persistent respiratory symptoms and airflow limitation and multiorgan impact. This affects the nutritional status of patients and requires multidimensional interventions including nutritional interventions according to individual metabolic needs. Our scoping review determined the effects of antioxidants in the treatment of COPD patients and their role in the decrease in the probability of exacerbations, hospital readmissions, and changes in lung function. The sources MEDLINE, LILACS, and Google Scholar were consulted and 19 studies were selected. The most indicated antioxidants are N-Acetylcysteine, vitamins E and D, and Zinc. Other antioxidants from plants or fruits extracts are also being investigated. The beneficial effect of antioxidants in stable or exacerbated patients is not clear, but theoretical and biological arguments of benefit justify lines of research that specify the impact on reducing oxidative stress and negative effects in COPD.

The role of micronutrient and immunomodulation effect in the vaccine era of COVID-19

Different dietary nutrients have distinct effects, including enhancing immune response activity and supporting mucous membrane integrity. These effects are critical in fighting against pathogenic agents, which cover coronavirus disease 2019 (COVID-19), the coronavirus disease that shuts down globally. Recent researches have shown that micronutrient deficiency is commonly associated with compromised immune responses, respiratory tract infections, or even susceptibility to COVID-19. The relationship between Vit A and infection is its role in mucosal epithelium integrity (skin and mucous membrane), the supplementation could be an option for assisted-treating the SARS-CoV-2 virus and a possible prevention of lung infection. Vit C/ascorbic acid stimulates oxygen radical scavenging activity of the skin and enhances epithelial barrier function. Ascorbic acid alone or with other natural compounds (baicalin and theaflavin) may inhibit the expression of angiotensin-converting enzyme II in human small alveolar epithelial cells and limited the entry of SARS-CoV-2. Vitamin D receptors can be expressed by immune cells, and different immune cells (macrophages, monocytes, dendritic cells, T cells, and B cells) can convert Vit D into its active form 1,25-(OH)2 D. Oral vitamin D intake can be a readily way to restrict the viral infection through downregulation of ACE2 receptor and to attenuate the disease severity by decreasing the frequency of cytokine storm and pulmonary pro-inflammatory response. Vit E supports T-cell mediated functions, optimization of Th1 response, and suppression of Th2 response. Vitamin E supplementation can lower the production of superoxides and may favors the antioxidants and benefit the progress of COVID-19 treatment. Zinc plays an essential role in both innate and adaptive immune systems and cytokine production, and Zinc-dependent viral enzymes to initiate the infectious process have proved the Zinc levels are directly associated with symptoms relieved of COVID-19. Iron is an essential component of enzymes involved in the activation of immune cells, lower iron levels predispose to severe symptoms of SARS-CoV-2, and monitoring the status can predict the disease severity and mortality. Selenium participates in the adaptive immune response by supporting antibody production and development. Deficiency can reduce antibody concentration, decreased cytotoxicity of NK cells, compromised cellular immunity, and an attenuated response to vaccination. The COVID-19 vaccines including three broad categories, protein-based vaccines, gene-based vaccines (mRNA vaccines and DNA vaccines), combination of gene and protein-based vaccines. Micronutrients are involved in immunity from the virus entering the human to innate immune response and adaptive immune response. Micronutrients are indispensable in immune response of vaccination.

The Induction of Alpha-1 Antitrypsin by Vitamin D in Human T Cells Is TGF-β Dependent: A Proposed Anti-inflammatory Role in Airway Disease

Background: Vitamin D upregulates anti-inflammatory and antimicrobial pathways that promote respiratory health. Vitamin D synthesis is initiated following skin exposure to sunlight, however nutritional supplementation can be required to address deficiency, for example during the winter months or due to cultural constraints. We recently reported that 1α,25-dihydroxyvitamin D3 (1,25(OH)₂D3) treatment induced alpha-1 antitrypsin (AAT) expression in CD4+, but not CD8+ T cells, with evidence supporting an immunoregulatory role.

Research Question: To understand the relationship between vitamin D, lung AAT levels and T lymphocytes further we investigated whether TGF-β is required as a co-factor for 1,25(OH)₂D3-induced upregulation of AAT by vitamin D in CD8+ T cells in vitro and correlated circulating vitamin D levels with lung AAT levels in vivo.

Results: 1,25(OH)₂D3 in combination with TGF-β1 increased AAT expression by CD8+ T cells, as well as VDR and RXRα gene expression, which may partly explain the requirement for TGF-β. CD4+ T cells may also require autocrine stimulation with TGF-β as a co-factor since 1,25(OH)₂D3 was associated with increased TGF-β bioactivity and neutralisation of TGF-β partially abrogated 1,25(OH)₂D3-induced SERPINA1 gene expression. Neither CD4+ nor CD8+ T cells responded to the circulating vitamin D precursor, 25-hydroxyvitamin D3 for induction of SERPINA1, suggesting that local generation of 1,25(OH)₂D3 is required. Transcriptional gene profiling studies previously demonstrated that human bronchial epithelial cells rapidly increased TGF-β2 gene expression in response to 1,25(OH)₂D3. Here, human epithelial cells responded to precursor 25(OH)D3 to increase bioactive TGF-β synthesis. CD8+ T cells responded comparably to TGF-β1 and TGF-β2 to increase 1,25(OH)₂D3-induced AAT. However, CD8+ T cells from adults with AAT-deficiency, homozygous for the Z allele of SERPINA1, were unable to mount this response. AAT levels in the airways of children with asthma and controls correlated with circulating 25(OH)D3.

Conclusions: Vitamin D increases AAT expression in human T cells and this response is impaired in T cells from individuals homozygous for the Z allele of SERPINA1 in a clinic population. Furthermore, a correlation between circulating vitamin D and airway AAT is reported. We propose that vitamin D-induced AAT contributes to local immunomodulation and airway health effects previously attributed to vitamin D.

Association of serum vitamin D levels with disease severity, systemic inflammation, prior lung function loss and exacerbations in a cohort of patients with chronic obstructive pulmonary disease (COPD)

Background

Vitamin D deficiency has been associated with chronic disorders including chronic obstructive pulmonary disease (COPD) but the relationships with inflammation, exacerbations and disease progression remain unclear.

Methods

In this monocentric cross-sectional observational study we analyzed the disease status, systemic inflammation, prior exacerbation frequency and loss in lung function in relation to serum 25-hydroxyvitamin D (25-OHD) levels in a cohort of 94 patients with COPD. Serum 25-OHD, C-reactive protein, interleukin-6 and tumor necrosis factor-α were quantified. Exacerbation frequencies and sunlight exposure were assessed. These parameters were analyzed in correlation to the current forced expiratory volume in 1 s (FEV₁), the individual average 3-year FEV₁ decline and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage.

Results

We observed fair correlation between serum 25-OHD and the current FEV₁ (r=0.38, P<0.001). Furthermore, mean serum 25-OHD was significantly altered between patients of GOLD stages I–IV (P=0.013). There was weak negative correlation of 25-OHD and the average annual change of the FEV₁ (r=−0.26, P<0.05). Furthermore, we observed fair negative correlation between 25-OHD and C-reactive protein (r=−0.32, P<0.01) as well as weak negative correlation with interleukin-6 (r=−0.23, P<0.05). While the exacerbation frequency significantly differed between GOLD stages (P=0.04), there was no direct association between exacerbations and 25-OHD levels.

Conclusion

Our data confirm frequent vitamin D deficiency in COPD and point out correlations between 25-OHD levels, systemic inflammation, disease severity and progression.

High parathyroid hormone predicts exacerbations in COPD patients with hypovitaminosis D

BACKGROUND

Hypovitaminosis D has been linked to deterioration in clinical parameters and lung function in COPD. As a response to low levels of vitamin D serum Parathyroid Hormone (iPTH) is increased in some, but not all, patients. The aim of this study was to determine whether COPD patients with elevated PTH levels are at higher risk of COPD exacerbations and hospitalizations.

METHODS

166 COPD outpatients were randomly preselected. Clinical and analytical characteristics were assessed at baseline. After excluding patients with other conditions known to disturb calcium metabolism 141 patients were identified. Except one, all patients were prospectively followed for 12 months after obtaining the blood samples. Hypovitaminosis D was considered when serum 25(OH)D < 30 ng/mL. Secondary hyperparathyroidism was considered when serum iPTH was higher than normal (50 pg/mL) in patients with hypovitaminosis D. COPD exacerbations and hospital admissions were recorded during the follow-up.

RESULTS

Prevalence of hypovitaminosis D in COPD patients was 89.3%, prevalence of secondary hyperparathyroidism associated with hypovitaminosis D was 22,9%. Cox proportional risk analysis showed that patients belonging to the high iPTH-low 25(OH)D group were at a higher risk of moderate COPD exacerbations (HR 1.81 (CI95% 1.043-3.127), p = 0.035) and hospital admissions (HR 5.45 (CI95% 2.018-14.720), p = 0.002) as compared with those with normal iPTH-low 25(OH)D levels.

CONCLUSIONS

COPD patients with hypovitaminosis D and elevated iPTH have higher risk of moderate exacerbations and hospitalizations than those with hypovitaminosis D and normal iPTH.

Restoration of Vitamin D Levels Improves Endothelial Function and Increases TASK-Like K+ Currents in Pulmonary Arterial Hypertension Associated with Vitamin D Deficiency

Background: Vitamin D (vitD) deficiency is highly prevalent in patients with pulmonary arterial hypertension (PAH). Moreover, PAH-patients with lower levels of vitD have worse prognosis. We hypothesize that recovering optimal levels of vitD in an animal model of PAH previously depleted of vitD improves the hemodynamics, the endothelial dysfunction and the ionic remodeling. Methods: Male Wistar rats were fed a vitD-free diet for five weeks and then received a single dose of Su5416 (20 mg/Kg) and were exposed to vitD-free diet and chronic hypoxia (10% O₂) for three weeks to induce PAH. Following this, vitD deficient rats with PAH were housed in room air and randomly divided into two groups: (a) continued on vitD-free diet or (b) received an oral dose of 100,000 IU/Kg of vitD plus standard diet for three weeks. Hemodynamics, pulmonary vascular remodeling, pulmonary arterial contractility, and K⁺ currents were analyzed. Results: Recovering optimal levels of vitD improved endothelial function, measured by an increase in the endothelium-dependent vasodilator response to acetylcholine. It also increased the activity of TASK-1 potassium channels. However, vitD supplementation did not reduce pulmonary pressure and did not ameliorate pulmonary vascular remodeling and right ventricle hypertrophy. Conclusions: Altogether, these data suggest that in animals with PAH and severe deficit of vitD, restoring vitD levels to an optimal range partially improves some pathophysiological features of PAH.