Clinical Phenotypes, Comorbidities, and Exacerbations according to Serum 25-OH Vitamin D and Plasma Fibrinogen Levels in Chronic Obstructive Pulmonary Disease

Vitamin D status in patients with chronic obstructive pulmonary disease at Chris Hani Baragwanath Hospital, Johannesburg, South Africa

Background

There has been a growing interest in nutritional/lifestyle factors, including vitamin D, that may affect chronic obstructive pulmonary disease (COPD). Most data are from Caucasian populations and temperate climates, with minimal African data.

Objectives

The primary objective was to determine the prevalence of vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) ≤20 ng/mL) and insufficiency (25(OH)D 21 - 29 ng/mL) among patients with COPD. Secondary objectives were to investigate the association between vitamin D and demographic/lifestyle factors, lung function parameters, markers of COPD severity and corticosteroid use.

Methods

A prospective, cross-sectional study of 76 patients with COPD was conducted at a tertiary hospital in Johannesburg, South Africa. Patients were interviewed regarding demographic/lifestyle factors, COPD severity markers and corticosteroid therapy. The most recent spirometry result was recorded. Blood samples were taken for measurement of calcium, alkaline phosphatase and vitamin D levels. Patients were stratified according to vitamin D status (deficiency and non-deficiency (25(OH)D >20 ng/mL, i.e. combined insufficiency and adequate levels)), and statistical analysis was performed to assess for associations.

Results

The sample included 72% males and 63% black African patients. The prevalences of vitamin D deficiency and insufficiency were 48% (95% confidence interval (CI) 42 - 54) and 35% (95% CI 30 - 41), respectively. A Modified Medical Research Council (mMRC) dyspnoea score ≥2 was associated with a relative risk of 1.34 (95% CI 1.05 - 1.7) for vitamin D deficiency in univariate analysis. In multivariate regression analysis, only sunlight exposure (<1 hour/day) was an independent predictor of vitamin D deficiency (odds ratio 2.4; 95% CI 1.3 - 4.5).

Conclusion

There was a high prevalence of suboptimal vitamin D levels in this COPD sample population. A higher mMRC score was associated with an increased risk of vitamin D deficiency, while low sunlight exposure was the only independent predictor of vitamin D deficiency.

Study synopsis

What the study adds. This is the first study to provide prevalence data regarding vitamin D status in COPD patients in sub-Saharan Africa. The study highlights a relationship between vitamin D status and both symptom severity and sunlight exposure.Implications of the findings. Owing to the high prevalence of suboptimal vitamin D status among COPD patients, it may be useful to screen patients for vitamin D deficiency, especially those with a more severe phenotype. There may be scope for further studies to evaluate whether vitamin D supplementation corrects the deficiency and provides any clinical outcome benefit.

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 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.

Are elevated plasma fibrinogen associated with lung function? An 8-year follow-up of the ELSA study

BACKGROUND

Fibrinogen is an important biomarker of inflammation, but findings from longitudinal studies that correlated fibrinogen with lung function in older adults are inconsistent.

AIM

To investigate the relationship between fibrinogen plasma levels and lung function impairment later in life.

METHODS

Longitudinal analysis of 2,150 participants of the English Longitudinal Study of Ageing (ELSA) aged 50 years and older. Associations between changes in plasma fibrinogen between waves 2 (2004-05) and 4 (2008-09) and lung function in wave 6 (2012-13) were performed using multiple linear regression adjusted by potential confounders.

RESULTS

Regarding the fibrinogen profile, 18.5% of the participants presented higher levels in both waves. In the adjusted models, the maintenance of high fibrinogen levels was associated with a significant reduction of lung function only for men. FEV1 showed a reduction of 0.17L, FVC of 0.22L, and the percentages predicted were 5.16% for FEV1 and 6.21% for FVC compared to those that maintained normal levels of fibrinogen.

DISCUSSION

To the best of our knowledge, this was the first study investigating the relationship between changes in fibrinogen levels over a long follow-up period and lung function in older adults without pre-existing chronic diseases. ELSA has information on critical demographic and clinical parameters, which allowed to adjust for potential confounding factors.

CONCLUSION

It was found that the persistence of high levels of plasma fibrinogen in older English men, but not women, is associated with lung function decline. Therefore, plasma fibrinogen showed to be an important biomarker of pulmonary dysfunction in this population.