Prevalence, determinants and clinical correlates of vitamin D deficiency in patients with Chronic Obstructive Pulmonary Disease in London, UK

The Role of Nutrition in the Development and Management of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a prevalent lung condition associated with significant morbidity and mortality. The management of COPD classically involves pulmonary rehabilitation, bronchodilators, and corticosteroids. An aspect of COPD management that is currently lacking in the literature is nutritional management, despite the prevalence of inadequate nutritional status in patients with COPD. In addition, certain nutritional imbalances have been reported to increase the risk of COPD development. This review summarizes the current literature on the role diet and nutrients may play in the risk and management of COPD development.

Immunomodulatory Effects of Vitamin D and Zinc on Viral Infection

Several nutrients are crucial in enhancing the immune system and preserving the structural integrity of bodily tissue barriers. Vitamin D (VD) and zinc (Zn) have received considerable interest due to their immunomodulatory properties and ability to enhance the body's immune defenses. Due to their antiviral, anti-inflammatory, antioxidative, and immunomodulatory properties, the two nutritional powerhouses VD and Zn are crucial for innate and adaptive immunity. As observed with COVID-19, deficiencies in these micronutrients impair immune responses, increasing susceptibility to viral infections and severe disease. Ensuring an adequate intake of VD and Zn emerges as a promising strategy for fortifying the immune system. Ongoing clinical trials are actively investigating their potential therapeutic advantages. Beyond the immediate context of the pandemic, these micronutrients offer valuable tools for enhancing immunity and overall well-being, especially in the face of future viral threats. This analysis emphasizes the enduring significance of VD and Zn as both treatment and preventive measures against potential viral challenges beyond the current health crisis. The overview delves into the immunomodulatory potential of VD and Zn in combating viral infections, with particular attention to their effects on animals. It provides a comprehensive summary of current research findings regarding their individual and synergistic impacts on immune function, underlining their potential in treating and preventing viral infections. Overall, this overview underscores the need for further research to understand how VD and Zn can modulate the immune response in combatting viral diseases in animals.

The impact of genetic variation within the vitamin D pathway upon skeletal muscle function: A systematic review

Studies in vitro have demonstrated a key molecular role for 1,25-dihydroxyvitamin D (1,25D) in skeletal muscle function, with vitamin D-deficiency (low serum 25-hydroxyvitamin D, 25D) being associated with muscle pain and weakness. Despite this, an understanding of the overall role of vitamin D in muscle health (particularly the impact of vitamin D-related genetic variants) has yet to be fully resolved, relative to more well-studied targets such as the skeleton. Thus, we aimed to review existing studies that have investigated relationships between skeletal muscle function and single nucleotide polymorphisms (SNPs) within vitamin D-related genes. A systematic review of papers published between January 2000 and June 2022 on PubMed, EMBASE and Web of Science pertaining to association between functionally relevant vitamin D receptor genetic variants and variants within genes of the vitamin D pathway and skeletal muscle function/outcomes was performed. 21 articles were included in the review for final analysis, of which 20 only studied genetic variation of the VDR gene. Of the included articles, 81 % solely included participants aged ≥ 50 years and of the 9 studies that did not only include White individuals, only 2 included Black participants. Within the vitamin D system, the VDR gene is the primary gene of which associations between polymorphisms and muscle function have been investigated. VDR polymorphisms have been significantly associated with muscle phenotypes in two or more studies. Of note A1012G was significantly associated with higher handgrip strength, but the results for other SNPs were notably variable between studies. While the lack of definitive evidence and study heterogeneity makes it difficult to draw conclusions, the findings of this review highlight a need for improvements with regards to the use of more diverse study populations, i.e., inclusion of Black individuals and other people of colour, and expanding research scope beyond the VDR gene.

Gender Differences in Vitamin D Status and Determinants of Vitamin D Insufficiency in Patients with Chronic Obstructive Pulmonary Disease

Low vitamin D levels are common in Chronic Obstructive Pulmonary Disease (COPD) and have been associated with various adverse COPD-related outcomes. Recent data on vitamin D status in representative COPD cohorts in Scandinavia is lacking. This study aimed to assess vitamin D status and determinants of vitamin D insufficiency in patients with COPD who were attending a specialist secondary care COPD clinic in Southwestern Sweden. All patients who visited the COPD clinic for their first medical visit during two periods, 2017−2018 and 2021, were included in this observational study. Measurements of 25-Hydroxyvitamin D (25(OH)D), clinical data and documentation of supplements containing vitamin D were collected retrospectively from patients’ medical records. Multivariable logistic regression analysis was performed to identify determinants of the primary outcome, vitamin D insufficiency (25(OH)D < 50 nmol/L). A total of 667 patients were included, and 33% had vitamin D insufficiency. The median 25(OH)D was 62 nmol/L (43.5−83.1 nmol/L). Vitamin D insufficiency was related to the male gender, current smoking habits, a lack of supplements containing vitamin D and the winter season for blood sampling. In conclusion, vitamin D insufficiency is common in patients with COPD. Men had significantly lower levels of vitamin D but took vitamin D-containing supplements less frequently compared to women. Our findings can help clinicians to identify patients who are at risk of vitamin D insufficiency and allow correction with supplementation where appropriate.

The causal association between genetically regulated 25OHD and chronic obstructive pulmonary disease: A meta-analysis and Mendelian randomization study

Backgrounds and objectives: Chronic obstructive pulmonary disease (COPD) is a multifactorial disease under genetic control. We present a meta-analysis to examine the associations of vitamin D binding protein (VDBP) gene rs7041 polymorphism with the risk of COPD and changes in circulating 25OHD concentrations.

Methods: A literature search, quality assessment, and data extraction were conducted independently by two investigators. Data are expressed as odds ratio (OR) or weighted mean difference (WMD) with a 95% confidence interval (CI). The inverse variance weighted method (IVW) in R (version 1.1.456) was applied to calculate the Mendelian randomization coefficient.

Results: A total of 13 articles with 3,667 participants were meta-analyzed. The rs7041-GT genotype was associated with a 49% reduced COPD risk (OR: 0.51, 95% CI: 0.30 to 0.88, p = 0.014) compared to the rs7041-TT genotype. Carriers of the rs7041-GT genotype had significantly higher concentrations of circulating 25OHD than those with the rs7041-TT genotype (WMD: 0.32 ng/ml, 95% CI: 0.09 to 0.55, p = 0.006). Under the assumptions of Mendelian randomization, and assuming a linear logistic relationship between circulating 25OHD and COPD, an inverse association was noted after using VDBP gene rs7041 polymorphism as an instrument (WMD: −2.07, 95% CI: −3.72 to −0.41, p = 0.015). There was a low probability of publication bias.

Conclusion: We observed significant associations of VDBP gene rs7041 polymorphism with the risk of COPD and changes in circulating 25OHD concentrations. Importantly, we found a causal relationship between genetically regulated 25OHD concentrations and COPD risk.

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.

Nutriepigenomics and chronic obstructive pulmonary disease: potential role of dietary and epigenetics factors in disease development and management

Over recent decades, a number of studies have revealed the possible role of different types of diets, as well as the nutritional elements they are made up of, in the pathogenesis of chronic obstructive pulmonary disease (COPD). To date, dietary factors have been identified to play a role in the prevention of COPD, with evidence from antioxidant nutrients, vitamins, and fiber intake. Additionally, certain dietary patterns such as the Mediterranean diet, together with other Western diets, provide evidence of the influence on COPD development, promoting lung health through nutritional approaches, and giving us an opportunity for intervention. The effect of diet on COPD is conveyed by 3 mechanisms: regulation of inflammation, oxidative stress, and carbon dioxide produced/oxygen intake. Current advances have begun to highlight the possible role of diet in modifying gene expression in certain individuals that predisposes them to COPD through epigenetic modifications. The relation between dietary intake and epigenetic factors has therefore outlined nutriepigenomics as a possible missing link in the relation between environmental exposure to smoke and the appearance of a subsequent chronic bronchial obstruction. This review summarizes the evidence regarding the influence of dietary patterns and nutrients and epigenetic regulatory mechanisms on COPD development and prevention with the aim of encouraging clinical research on the impact of dietary modifications on COPD-related clinical outcomes. This review highlights the importance of proposing and carrying out future studies focused on the modulating effects of certain nutrients on epigenetic changes in patients with specific COPD phenotypes (bronchiectasis, emphysema, asthma/COPD, chronic bronchitis), and their individual responses to cigarette smoking, environmental pollution, or other noxious particles. The objectives of these future studies must be directed to the development of novel therapeutic approaches and personalized management of COPD.

Nutrition as a modifiable factor in the onset and progression of pulmonary function impairment in COPD: a systematic review

CONTEXT

Chronic obstructive lung disease (COPD) is a progressive lung disease characterized by persistent airflow limitation. An increasing amount of evidence suggests an effect of dietary quality on the risk of COPD in the general population and pulmonary function decline in patients with COPD.

OBJECTIVE

The association of dietary intake and nutrient status with COPD risk and onset, as well as pulmonary function decline (change in forced expiratory volume in 1 second, forced vital capacity, or the ratio of the former to the latter) in patients with COPD was investigated in this systematic review.

DATA SOURCES

The PubMed database was searched by combining terms of pulmonary function or COPD with diet, nutrient status, or nutritional supplementation.

DATA EXTRACTION

Original studies and systematic reviews and meta-analyses were included. Articles obtained were independently screened for relevance on the bases of title and abstract by 2 researchers. Eventually, 89 articles were included in the analysis.

RESULTS

The unhealthy Western-style diet is associated with an increased risk of COPD and an accelerated decline of pulmonary function. Intake of fruit, vegetables, dietary fibers, vitamins C and E, polyphenols, and β-carotene were individually associated with lower COPD risk, whereas consumption of processed meat was associated with higher COPD risk. Data on the effect of dietary quality on pulmonary function decline in patients with COPD are limited and inconsistent. Strong evidence for beneficial effects on pulmonary function decline was found only for vitamin D supplementation.

CONCLUSION

Considering the increasing burden of COPD, more attention should be given to dietary quality as a modifiable factor in disease development and progression in patients with COPD.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021240183.

Clinical Significance of Analysis of Vitamin D Status in Various Diseases

Vitamin D plays a role not only in the proper functioning of the skeletal system and the calcium-phosphate equilibrium, but also in the immune system, the cardiovascular system and the growth and division of cells. Although numerous studies have reported on the analysis of vitamin D status in various groups of patients, the clinical significance of measurements of vitamin D forms and metabolites remains ambiguous. This article reviews the reports analyzing the status of vitamin D in various chronic states. Particular attention is given to factors affecting measurement of vitamin D forms and metabolites. Relevant papers published during recent years were identified by an extensive PubMed search using appropriate keywords. Measurement of vitamin D status proved to be a useful tool in diagnosis and progression of metabolic syndrome, neurological disorders and cancer. High performance liquid chromatography coupled with tandem mass spectrometry has become the preferred method for analyzing the various forms and metabolites of vitamin D in biological fluids. Factors influencing vitamin D concentration, including socio-demographic and biochemical factors as well as the genetic polymorphism of the vitamin D receptor, along with vitamin D transporters and enzymes participating in vitamin D metabolism should be considered as potential confounders of the interpretation of plasma total 25(OH)D concentrations.

Associations Among 25-Hydroxyvitamin D Levels, Lung Function, and Exacerbation Outcomes in COPD: An Analysis of the SPIROMICS Cohort

BACKGROUND

The relationship between 25-hydroxyvitamin D (25-OH-vitamin D) and COPD outcomes remains unclear. Using the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS), we determined associations among baseline 25-OH-vitamin D and cross-sectional and longitudinal lung function and COPD exacerbations.

METHODS

Serum 25-OH-vitamin D level was measured in stored samples from 1,609 SPIROMICS participants with COPD. 25-OH-vitamin D levels were modeled continuously and dichotomized as deficient (< 20 ng/mL) vs not deficient (≥ 20 ng/mL). Outcomes of interest included % predicted FEV1 (current and 1-year longitudinal decline) and COPD exacerbations (separately any and severe, occurring in prior year and first year of follow-up).

RESULTS

Vitamin D deficiency was present in 21% of the cohort and was more prevalent in the younger, active smokers, and blacks. Vitamin D deficiency was independently associated with lower % predicted FEV1 (by 4.11%) at enrollment (95% CI, -6.90% to -1.34% predicted FEV1; P = .004), 1.27% predicted greater rate of FEV1 decline after 1 year (95% CI, -2.32% to -0.22% predicted/y; P = .02), and higher odds of any COPD exacerbation in the prior year (OR, 1.32; 95% CI, 1.00-1.74; P = .049). Each 10-ng/mL decrease in 25-OH-vitamin D was associated with lower baseline lung function (-1.04% predicted; 95% CI, -1.96% to -0.12% predicted; P = .03) and increased odds of any exacerbation in the year before enrollment (OR, 1.11; 95% CI, 1.01-1.22; P = .04).

CONCLUSIONS

Vitamin D deficiency is associated with worse cross-sectional and longitudinal lung function and increased odds of prior COPD exacerbations. These findings identify 25-OH-vitamin D levels as a potentially useful marker of adverse COPD-related outcomes.

Translating vitamin D transcriptomics to clinical evidence: Analysis of data in asthma and chronic obstructive pulmonary disease, followed by clinical data meta-analysis

Vitamin D (VitD) continues to trigger intense scientific controversy, regarding both its bi ological targets and its supplementation doses and regimens. In an effort to resolve this dispute, we mapped VitD transcriptome-wide events in humans, in order to unveil shared patterns or mechanisms with diverse pathologies/tissue profiles and reveal causal effects between VitD actions and specific human diseases, using a recently developed bioinformatics methodology. Using the similarities in analyzed transcriptome data (c-SKL method), we validated our methodology with osteoporosis as an example and further analyzed two other strong hits, specifically chronic obstructive pulmonary disease (COPD) and asthma. The latter revealed no impact of VitD on known molecular pathways. In accordance to this finding, review and meta-analysis of published data, based on an objective measure (Forced Expiratory Volume at one second, FEV₁%) did not further reveal any significant effect of VitD on the objective amelioration of either condition. This study may, therefore, be regarded as the first one to explore, in an objective, unbiased and unsupervised manner, the impact of VitD levels and/or interventions in a number of human pathologies.

Chronic Obstructive Pulmonary Disease: A 2019 Evidence Analysis Center Evidence-Based Practice Guideline

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder in which patients are at high risk for both pulmonary and systemic complications of their disease. Medical nutrition therapy by a registered dietitian nutritionist can be an integral component of lifestyle treatment targeted at maintaining and improving outcomes, such as lung function, mortality, and quality of life. The Academy of Nutrition and Dietetics (Academy) convened an expert workgroup to conduct a systematic review to update the COPD Evidence-Based Nutrition Practice Guideline. This publication outlines the Academy's Evidence Analysis Library methods used to complete the systematic review and guideline and examines the recommendations and supporting evidence. A total of 14 recommendations were developed based on evidence from eight conclusions. Using the Nutrition Care Process as a framework for practice, recommendations rated as strong included assessing and monitoring and evaluating body weight and medical nutrition therapy by a registered dietitian nutritionist. Weak recommendations included predicting resting and total energy expenditure. All other recommendations were rated as fair. These included individualizing the calorie prescription and macronutrient composition of the diet; assessing and monitoring and evaluating energy intake, serum 25-hydroxyvitamin D levels, and frequency of exacerbations; and determining need for vitamin D supplementation. Fewer than one-third of the systematic review's conclusions could be used to support the recommendations due to conflicting results or limited or no evidence available. The Evidence Analysis Library 2019 COPD Evidence-Based Nutrition Practice Guideline is a valuable resource for registered dietitian nutritionists and other health care professionals caring for those with COPD.

Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases: Utopia or Strategy With Potential?

Patients with respiratory diseases such as cystic fibrosis, chronic obstructive pulmonary disease, or asthma often experience an acute worsening of respiratory symptoms, termed exacerbations. Although the course of exacerbations is disease specific, they are mostly triggered by a respiratory infection. Exacerbations often require hospitalization and are an important cause of mortality. Treatments of exacerbations aim to minimize the negative impact and to prevent subsequent events. Despite many existing therapy options, many patients do not benefit from therapy and suffer from recurrent events. Vitamin D deficiency is a worldwide problem and is extremely prevalent in these patients. Vitamin D, known for its calcemic effects, also has immunomodulatory and anti-infectious actions and can therefore be a possible agent to treat or prevent exacerbations. This review will focus on vitamin D as a potential candidate to treat or prevent exacerbations in CF, COPD, and asthma.

The (Sun)Light and Dark of 25-Hydroxyvitamin D Testing

Background

Vitamin D is obtained by the body via sunlight on the skin, from the diet, or from supplementation. The primary function of vitamin D is to maintain calcium homeostasis and bone health, but in the past decade, numerous other health benefits have been proposed.

Content

With the increased awareness of the potential benefits of maintaining sufficient concentrations of 25-hydroxyvitamin D, clinicians began ordering this test for their patients much more frequently. The number of available methods increased, but with that came a larger focus on the challenges of measuring 25-hydroxyvitamin D accurately due to binding to vitamin D-binding protein and the presence of other vitamin D metabolites. Further, standardization of these assays became a focus for several organizations so that clinical guidelines can be applicable to every patient regardless of what methodology is used in 25-hydroxyvitamin D measurement.

Summary

Improvements are being made in the specificity, accuracy, and standardization of the measurement of 25-hydroxyvitamin D, and the future of this testing is looking brighter.

Comparison of the Association between Circulating Vitamin D3 Levels and Clinical Outcomes in Patients with Asthma and Chronic Obstructive Pulmonary Disease: A Prospective Observational Study

Vitamin D has an immune-modulating effect, related to the pathophysiology of asthma and chronic obstructive pulmonary disease (COPD). However, few studies have focused on the difference between patients with asthma and COPD in the association of circulating vitamin D levels with clinical outcomes. We sought to investigate the associations of circulating vitamin D levels with health-related QOL (HR-QOL), severity, and exacerbations. Subjects included 152 asthma patients and 50 COPD patients. We measured plasma concentrations of 25-hydroxyvitamin D₃ [25(OH)D₃]. HR-QOL was assessed using the EuroQoL 5-Dimension (EQ-5D) and the 12-item Short Form Health Survey (SF-12) scales. Exacerbations were recorded during a one-year follow-up. Associations between plasma 25 (OH)D₃ concentrations and outcome variables were evaluated using linear regression. Plasma concentrations of 25(OH)D₃ were positively associated with the EQ-5D index value and the SF-12 physical component score in patients with asthma; however, such associations were not observed in patients with COPD. A significant association between severity and plasma concentrations of 25(OH)D₃ was found only in patients with COPD. The hazard ratios (95% confidence interval) of plasma 25(OH)D₃ concentrations (per 1 ng/mL decrease) for time to first exacerbation was 1.38 (1.10-1.75; p = 0.006) and 0.95 (0.87-1.03; p = 0.179) in patients with COPD and asthma, respectively. Lower concentrations of plasma 25(OH)D₃ contributed to lower HR-QOL in patients with asthma, and were associated with severity and risk of future exacerbations in patients with COPD.

The Levels of Vitamin D, Metalloproteinase-9 and Tissue Inhibitor Metalloproteinase-1 in COPD Patients, Healthy Smokers and Non-Smokers of Indonesian Citizens

BACKGROUND:

Exposure to cigarette smoke may stimulate the inflammatory response and activate polymorphonuclear leukocytes, thus resulting in secretion of cellular proteases. Vitamin D has the potential to modulate the inflammatory response to harmful particles in patients with Chronic Obstructive Pulmonary Disease (COPD).

AIM:

This study aimed to determine the levels of vitamin D, MMP-9, and TIMP-1 in COPD subjects, healthy smokers and nonsmokers of Indonesian citizens

METHODS:

Seventy-eight male subjects took part in this study. They comprised three groups, i.e. COPD (n = 26), healthy smokers (n = 25) and healthy non-smokers (n = 27). Serum 25(OHD) levels, MMP-9, and TIMP-1 concentrations measured by electrochemiluminescence binding assay (ECLIA) and enzyme-linked immunosorbent assay (ELISA).

RESULTS:

The levels of vitamin D in COPD (21.96 ± 6.62ng/mL) and healthy smokers (27.87 ± 7.08 ng/mL) were significantly (p < 0.001) lower compared to that in healthy non-smokers (31.71 ± 9.24 ng/mL). On contrary, the levels of MMP-9 in COPD (11.98 ± 41.54 ng/mL) was significantly (p = 0.003) higher compared to that in healthy smokers (2.23 ± 3.39 ng/mL) and healthy non-smokers (0.89 ± 1.12 ng/mL). Whereas the levels of TIMP-1 in healthy smokers (24.64 ± 57.77 ng/mL) was significantly (p < 0.001) lower compared to that in COPD (58.40 ± 77.53 ng/mL) and healthy non-smokers (46,54 ± 71,48 ng/mL).

CONCLUSION:

The present study showed the lowest level of vitamin D, the highest level of MMP-9 and TIMP-1 in the COPD subjects.

Systematic Review and Meta-Analysis to Establish the Association of Common Genetic Variations in Vitamin D Binding Protein With Chronic Obstructive Pulmonary Disease

Background: Vitamin-D binding protein (DBP) also known as GC protein, is a major determinant for vitamin- D metabolism and transport. GC1F, GC1S, and GC2 are the three allelic variants (denoted as rs4588 and rs7041) of GC, and known to be associated with chronic obstructive pulmonary disease (COPD). However, contradictory reports and population specific risk attributed by these alleles warranted detailed genetic epidemiology study to establish the association between GC variants and COPD. In this study we performed a meta-analysis and investigated the genetic architecture of GC locus to establish the association and uncover the plausible reason for allelic heterogeneity. Methods: Published cross-sectional case control studies were screened and meta-analysis was performed between GC variants and COPD outcome. RevMan-v5.3 software was used to perform random and/or fixed models to calculate pooled odds ratio (Meta-OR). Linkage disequilibrium (LD) and haplotypes at GC locus were evaluated using 1000 Genomes genotype data. In silico functional implications of rs4588 and rs7041 was tested using publicly available tools. Results: GC1F allele and GC1F/1F genotype were found to confer COPD risk in overall meta-analysis. GC1S/1S was found to confer risk only among Europeans. In silico investigation of rs4588 and rs7041 identified strong eQTL effects and potential role in regulation of GC expression. Large differences in allele frequencies, linkage disequilibrium (LD) and haplotypes were identified at GC locus across different populations (Japanese, African, Europeans, and Indians), which may explain the variable association of different GC alleles in different populations. Conclusion: GC1F and GC1F/1F impose significant genetic risk for COPD, among Asians. Considerable differences in allele frequencies and LD structure in GC locus may impose population specific risk.

Vitamin D to prevent exacerbations of COPD: systematic review and meta-analysis of individual participant data from randomised controlled trials

BACKGROUND

Randomised controlled trials (RCTs) of vitamin D to prevent COPD exacerbations have yielded conflicting results.Individual participant data meta-analysis could identify factors that explain this variation.

METHODS

PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science were searched from inception up to and including 5 October 2017 to identify RCTs of vitamin D supplementation in patients with COPD that reported incidence of acute exacerbations. Individual participant data meta-analysis was performed using fixed effects models adjusting for age, sex, Global Initiative for Chronic Obstructive Lung Disease spirometric grade and trial.

RESULTS

Four eligible RCTs (total 560 participants) were identified; individual participant data were obtained for 469/472 (99.4%) participants in three RCTs. Supplementation did not influence overall rate of moderate/severe COPD exacerbations (adjusted incidence rate ratio (aIRR) 0.94, 95% CI 0.78 to 1.13). Prespecified subgroup analysis revealed that protective effects were seen in participants with baseline 25-hydroxyvitamin D levels <25 nmol/L (aIRR 0.55, 95% CI 0.36 to 0.84) but not in those with baseline 25-hydroxyvitamin D levels ≥25 nmol/L (aIRR 1.04, 95% CI 0.85 to 1.27; p for interaction=0.015). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (adjusted OR 1.16, 95% CI 0.76 to 1.75).

CONCLUSIONS

Vitamin D supplementation safely and substantially reduced the rate of moderate/severe COPD exacerbations in patients with baseline 25-hydroxyvitamin D levels <25 nmol/L but not in those with higher levels.

TRIAL REGISTRATION NUMBER

CRD42014013953.

Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level

Context:

The global scenario of illness is shifting from infectious diseases to non-communicable diseases, with chronic conditions such as heart diseases, stroke and Chronic Obstructive Pulmonary Disease (COPD) now being chief causes of death globally and more than 90% of deaths due to COPD occur in low and midline income countries.[1] Low serum vitamin D level is associated with various lung diseases and decreased lung function.[2]

Aims:

This study was designed to study the serum vitamin D level and its correlation with severity of COPD as assessed by spirometry, COPD assessment test (CAT) and exercise capacity and BMI of COPD patients.

Settings and Design:

Observational cross sectional study conducted on patients of COPD attending the outpatient department.

Materials and Methods:

One hundred sixty consecutive patients of COPD attending the outpatient Department were included in the study. Pack years, CAT score, 6 minute walk distance, post bronchodilator spirometry values and BMI was recorded along with complete history and physical examination.

Statistical Analysis Used:

Data analysis was done using IBM SPSS 23 software. Descriptive statistics, Independent sample t test, ANOVA and Pearson correlation were applied.

Results:

A significant positive correlation was found between FeV1% of predicted and serum Vitamin D level(r = 0.291; P < 0.001). A negative correlation was found between serum Vitamin D level and severity of COPD as assessed by CAT score (r = -0.355; P < 0.001). Also, a significant positive correlation was found between vitamin D levels and exercise capacity as assessed by 6 minute walk test (6MsWT) (r = 0.648; P < 0.001).

Conclusions:

COPD patients with more severe disease tend to have lower serum Vitamin D levels. As it is an immunomodulator affecting various inflammatory pathways, it is imperative that we give due consideration to Vitamin D levels in managing patients of COPD.

Vitamin D status is associated with muscle strength and quality of life in patients with COPD: a seasonal prospective observation study

Background

Owing to hospitalization, reduced functional capacity and consequently, less sunlight exposure, suboptimal vitamin D status (25-hydroxyvitamin D [25(OH)D]⩽50 nmol/L) is prevalent among COPD patients.

Objective

This study aimed to investigate seasonal changes in vitamin D status and any associated changes in fat-free mass (FFM), muscle strength and quality of life (QoL) in COPD patients.

Patients and methods

COPD patients living in Northern Ireland (n=51) completed study visits at the end of winter (March/April) and at the end of summer (September/October), corresponding to the nadir and peak of vitamin D status, respectively. At both time points, serum concentration of 25(OH)D was quantified by liquid chromatography-tandem mass spectrometry, FFM (kg) was measured using bioelectrical impedance and muscle strength (kg) was measured using handgrip dynamometry. QoL was assessed using the validated St George’s Respiratory Questionnaire.

Results

Mean±SD 25(OH)D concentration was significantly higher at the end of summer compared to the end of winter (52.5±30.5 nmol/L vs 33.7±28.4 nmol/L, P<0.001); and house- bound patients had significantly lower 25(OH)D concentration compared to nonhousebound patients at the end of summer (42.9±4.2 vs 57.2±9.9 nmol/L; P⩽0.001). Muscle strength (at both time points) and QoL (end of summer only) were positively predicted by 25(OH)D concentration, independent of age, sex and smoking status.

Conclusion

This study highlights the need for health policies to include a recommendation for year-round vitamin D supplementation in housebound COPD patients, and wintertime supplementation in nonhousebound patients, to maintain optimal 25(OH)D concentrations to protect musculoskeletal health. Furthermore, an optimal vitamin D status may have potential benefits for QoL in these patients.

Vitamin D receptor genotype influences risk of upper respiratory infection

SNP in the vitamin D receptor (VDR) gene is associated with risk of lower respiratory infections. The influence of genetic variation in the vitamin D pathway resulting in susceptibility to upper respiratory infections (URI) has not been investigated. We evaluated the influence of thirty-three SNP in eleven vitamin D pathway genes (DBP, DHCR7, RXRA, CYP2R1, CYP27B1, CYP24A1, CYP3A4, CYP27A1, LRP2, CUBN and VDR) resulting in URI risk in 725 adults in London, UK, using an additive model with adjustment for potential confounders and correction for multiple comparisons. Significant associations in this cohort were investigated in a validation cohort of 737 children in Manchester, UK. In all, three SNP in VDR (rs4334089, rs11568820 and rs7970314) and one SNP in CYP3A4 (rs2740574) were associated with risk of URI in the discovery cohort after adjusting for potential confounders and correcting for multiple comparisons (adjusted incidence rate ratio per additional minor allele ≥1·15, P for trend ≤0·030). This association was replicated for rs4334089 in the validation cohort (P for trend=0·048) but not for rs11568820, rs7970314 or rs2740574. Carriage of the minor allele of the rs4334089 SNP in VDR was associated with increased susceptibility to URI in children and adult cohorts in the United Kingdom.

The burgeoning role of cytochrome P450-mediated vitamin D metabolites against colorectal cancer

The metabolites of vitamin D₃ (VD3) mediated by different cytochrome P450 (CYP) enzymes, play fundamental roles in many physiological processes in relation to human health. These metabolites regulate a variety of cellular signal pathways through the direct binding of activated vitamin D receptor/retinoic X receptor (VDR/RXR) heterodimeric complex to specific DNA sequences. Thus, the polymorphisms of VDR and VD3 metabolizing enzymes lead to differentiated efficiency of VD3 and further affect serum VD3 levels. Moreover, VDR activation is demonstrated to inhibit the growth of various cancers, including colorectal cancer. However, excessive intake of vitamin D may lead to hypercalcemia, which limits the application of vitamin D tremendously. In this review, we have summarized the advances in VD3 research, especially the metabolism map of VD3 and the molecular mechanisms of inhibiting growth and inducing differentiation in colorectal cancer mediated by VDR-associated cellular signal pathways. The relationship between VDR polymorphism and the risk of colorectal cancer is also illustrated. In particular, novel pathways of the activation of VD3 started by CYP11A1 and CYP3A4 are highlighted, which produce several noncalcemic and antiproliferative metabolites. At last, the hypothesis is put forward that further research of CYP-mediated VD3 metabolites may develop therapeutic agents for colorectal cancer without resulting in hypercalcemia.