Serum vitamin D in patients with chronic obstructive lung disease does not correlate with mortality--results from a 10-year prospective cohort study

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.

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.

Two-Year Mortality Following a Severe COPD Exacerbation in Bulgarian Patients

Two-year mortality in patients with COPD is expected to be between 10% and 49% depending on the investigated subgroup and specific patients’ characteristics.

Aim: To assess the two-year mortality in COPD patients following hospitalization for severe exacerbation and to describe the prognostic value of comorbidities and specific patients’ characteristics.

Materials and methods: We included 152 consecutive patients hospitalized for COPD exacerbation and signing informed consent. The Metabolic syndrome (MS), diabetes mellitus (DM), and hypovitaminosis D were diagnosed according to international guidelines. Demographic parameters (age, sex, smoking status, and the number of pack-years) were recorded. Quality of life was examined using CAT and mMRC questionnaires. The lung function was assessed by spirometry. Two-year mortality was determined according to data extracted from the national death register.

Results: Two-year mortality rate was 11.8%. The investigated comorbidities – DM, MS, arterial hyper-tension (AH) and vitamin D status were no predictors of the two-year mortality. Mortality was increased in patients with mMRC ≥ 2 (17.2 vs. 1.9%, p = 0.005) and CAT score ≥ 10 (14.2 vs. 0%, p = 0.045). Severe exacerbation during the previous year was a risk factor for the registered two-year mortality (17.5% vs 5.6%, p = 0.021). The two-year mortality was increased in the group with FEV1 < 50%, compared to FEV1 > 50% (18.0 vs. 7.7%, p = 0.049). Cox regression analysis showed a 3.0% increase in the mortality rate for each 1% decrease in FEV1, 6.2% for each 1% decrease in PEF, 7.8% for one year of increasing age, 4% for 1% decrease in the FEV1/FVC ratio and 7.1% for each 1 point increase of CAT (all p-values < 0.05).

Conclusions: The two-year mortality of COPD patients following a severe exacerbation was relatively low. Chronological age, FEV1, history for severe exacerbation during the previous year, reduced quality of life, and low BMI were all associated with increased mortality. Disease Grade C, mMRC < 2, and CAT score < 10 were associated with a favourable prognosis.

Vitamin D deficiency, impaired lung function and total and respiratory mortality in a cohort of older men: cross-sectional and prospective findings from The British Regional Heart Study

OBJECTIVES

Vitamin D deficiency is associated with chronic obstructive pulmonary disease (COPD). We examined the cross-sectional association between 25-hydroxyvitamin D (25(OH)D) and lung function impairment and assessed whether vitamin D deficiency is related to long-term mortality in those with impaired lung function.

DESIGN

Prospective study SETTING: General practices in the UK.

PARTICIPANTS

3575 men aged 60-79 years with no prevalent heart failure.

OUTCOME MEASURES

Airway obstruction and mortality. The Global Initiative on Obstructive Lung diseases (GOLD) spirometry criteria was used to define airway obstruction.

RESULTS

During the follow-up period of 20 years, there were 2327 deaths (114 COPD deaths). Vitamin D deficiency was defined as serum 25(OH)D levels<10 ng/mL; insufficiency as 25(OH)D 10-19 ng/mL; sufficient as 25(OH)D>20 ng/mL. In cross-sectional analysis, vitamin D deficiency was more prevalent in those with moderate COPD (FEV/FVC <70% and FEV₁ 50 to <80%; FEV₁, forced expiratory volume in 1 s and FVC, forced vital capacity) and severe COPD (FEV/FVC <70% and FEV₁ <50%) but not in those with mild COPD (FEV/FVC <70% and FEV₁>80%) or restrictive lung disease (FEV₁/FVC >70% and FVC <80%) compared with men with normal lung function . Vitamin D deficiency was associated with increased risk of total and respiratory mortality in both men with COPD and men with restrictive lung disease after adjustment for confounders and inflammation. The adjusted HRs (95% CI) for total mortality comparing levels of 25(OH)D<10 ng/mL to 25(OH)D>=20 ng/mL were 1.39 (1.10 to 1.75), 1.52 (1.17 to 1.98), 1.58 (1.17 to 2.14) and 1.39 (0.83 to 2.33) for those with no lung impairment, restrictive lung function, mild/moderate COPD and severe COPD, respectively.

CONCLUSION

Men with COPD were more likely to be vitamin D deficient than those with normal lung function. Vitamin D deficiency is associated with increased all-cause mortality in older men with no lung impairment as well as in those with restrictive or obstructive lung impairment.

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.

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.

Airway obstruction, serum vitamin D and mortality in a 33-year follow-up study

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease and low vitamin D status predict mortality, but their combined effect on mortality remains inconclusive. We aimed to investigate a joint effect of airway obstruction and vitamin D status on mortality in a nationally representative cohort.

METHODS

We analysed data of 6676 Finnish adults participating between 1978 and 1980 in a national health examination survey, undergoing spirometry and having all necessary data collected. We followed them up in national registers through record linkage until 31 December 2011. We categorised the subjects with obstruction using the lower limit of normal (LLN) and the measured serum 25-hydroxyvitamin-D (s-25(OH)D) into tertiles.

RESULTS

Both obstruction and low s-25(OH)D independently predicted mortality in a multivariate model adjusted also for age, sex, smoking, education, leisure physical activity, body mass index, asthma and serum C-reactive protein. However, a statistically significant (p = 0.007) interaction emerged: the adjusted mortality HRs (95% CI's) for s-25(OH)D in tertiles among the subjects without and with obstruction were 1.00 (lowest), 0.96 (0.87-1.05) and 0.89 (0.81-0.98); and 1.00, 0.96 (0.71-1.31) and 0.57 (0.40-0.80), respectively.

CONCLUSIONS

In conclusion, obstruction and low s-25(OH)D predict mortality independently of each other. Our findings suggest that low vitamin D status might be particularly detrimental among subjects with obstruction.

Low concentrations of 25-hydroxyvitamin D and long-term prognosis of COPD: a prospective cohort study

Role and importance of vitamin D deficiency in long-term prognosis of chronic obstructive pulmonary disease (COPD) still remains undetermined. We tested the hypothesis that among individuals with COPD, those with low concentrations of 25-hydroxyvitamin D have a poorer prognosis compared to those with normal concentrations. We studied 35,153 individuals from the general population aged 20-100 years with 25-hydroxyvitamin D measurements and spirometry, the Copenhagen City Heart Study [median follow-up 21 years (range 13 days-36 years)] and the Copenhagen General Population Study [7.1 years (3 days-13 years)]. Spirometric COPD (n = 5178; 15% of all) was defined as forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) < 0.70 in individuals without asthma and clinical COPD (n = 2033; 6%) as FEV₁/FVC < 0.70 and FEV₁ < 80% of predicted in ever-smokers aged > 40 years without asthma and with cumulative tobacco consumption ≥ 10 pack-years. In spirometric COPD, median age at death in years was 70.2 (95% confidence interval [CI] 64.4-71.2) for individuals with 25-hydroxyvitamin D < 12.5 nmol/L and 80.3 (74.4-83.4) for those with ≥ 50 nmol/L. In clinical COPD, corresponding values were 69.0 (63.3-70.9) and 76.2 (73.8-78.0). In spirometric COPD, multivariable adjusted hazard ratios for individuals with 25-hydroxyvitamin D < 12.5 nmol/L versus those with ≥ 50 nmol/L were 1.35 (95% CI 1.09-1.67) for all-cause mortality, 1.63 (1.00-2.64) for respiratory mortality, 1.14 (0.76-1.70) for cardiovascular mortality, 1.37 (0.90-2.06) for cancer mortality, and 1.61 (1.04-2.49) for other mortality. In clinical COPD, corresponding values were 1.39 (1.07-1.82), 1.57 (0.91-2.72), 0.88 (0.51-1.53), 1.63 (0.99-2.67), and 2.00 (1.12-3.56). Low concentrations of 25-hydroxyvitamin D were associated with an increased risk of death in individuals with COPD. No clear pattern of association could be observed for cause of death; however, there may be an increased risk of respiratory, cancer, and other mortality. It is likely that low concentrations of 25-hydroxyvitamin D is a marker of poor health in COPD.

Vitamin D and respiratory health in the Busselton Healthy Ageing Study

BACKGROUND AND OBJECTIVE

The relationship between vitamin D and respiratory disease was examined by cross-sectional analysis of a large community-based sample.

METHODS

Serum 25-hydroxyvitamin D (25OHD) and history of respiratory disease, symptoms (recorded by questionnaire) and spirometry were measured in 5011 adults aged 45-69 years. Adjustments were made for age, sex, season and smoking (Model A), plus body mass index (BMI) and physical activity level (Model B), plus history of chronic diseases (Model C).

RESULTS

Mean (SD) age was 58 (SD 6) years with 45% males, 10% current smokers and 12% taking vitamin D supplements. The prevalence of 25OHD level <50 nmol/L was 8.0%. In all the three models, 25OHD <50 nmol/L was significantly associated with asthma (Model C: odds ratio (OR): 1.32; 95% CI: 1.00, 1.73), bronchitis (1.54; 1.17, 2.01), wheeze (1.37; 1.10, 1.71) and chest tightness (1.42; 1.10, 1.83). Participants with vitamin D level > 100 nmol/L had higher forced vital capacity (FVC) in all the three models (1.17% higher, compared with the 50-100 nmol/L group in Model C).

CONCLUSION

Low levels of serum 25OHD were independently associated with asthma, bronchitis, wheeze and chest tightness after three levels of adjustment for potential confounders. Higher vitamin D levels were associated with higher levels of lung function.

One-year mortality after severe COPD exacerbation in Bulgaria

Introduction

One-year mortality in COPD patients is reported to be between 4% and 43%, depending on the group examined.

Aim

To examine the one-year mortality in COPD patients after severe exacerbation and the correlation between mortality and patients’ characteristics and comorbidities.

Methods

A total of 152 COPD patients hospitalized for severe exacerbation were assessed for vitamin D status, diabetes mellitus (DM), arterial hypertension (AH), and metabolic syndrome (MS). Data were gathered about smoking status and number of exacerbations in previous year. CAT and mMRC questionnaires were completed by all patients. Pre- and post-bronchodilatory spirometry was performed. One-year mortality was established from national death register.

Results

One-year mortality is 7.2%. DM, MS, and VD are not predictors for one-year mortality. However there is a trend for increased mortality in patients with AH (9.5% vs. 2.1%, p = 0.107). There is increased mortality in patients with mMRC > 2 (11.1 vs. 0%, p = 0.013). The presence of severe exacerbation in the previous year is a risk factor for mortality (12.5% vs. 1.4%, p = 0.009). There is a trend for increased mortality in the group with FEV1 < 50% (11.5 vs. 4.4%, p = 0.094). Cox regression shows 3.7% increase in mortality rate for 1% decrease in FEV1, 5.2% for 1% decrease in PEF, 7.8% for one year age increase and 8.1% for 1 CAT point increase (all p < 0.05).

Conclusions

This study finds relatively low one-year mortality in COPD patients after surviving severe exacerbation. Grade C and FEV1 > 80% may be factors for good prognosis. Risk factors for increased mortality are age, FEV1 value, severe exacerbation in previous year and reduced quality of life.

The association between vitamin D and COPD risk, severity, and exacerbation: an updated systematic review and meta-analysis

Background

In recent years, the pleiotropic roles of vitamin D have been highlighted in various diseases. However, the association between serum vitamin D and COPD is not well studied. This updated systematic review and meta-analysis aimed to assess the relationship between vitamin D and the risk, severity, and exacerbation of COPD.

Methods

A systematic literature search was conducted in PubMed, Medline, EMBASE, Chinese National Knowledge Infrastructure, Wanfang, and Weipu databases. The pooled risk estimates were standardized mean difference (SMD) with 95% confidence interval (CI) for vitamin D levels and odds ratio (OR) with 95% CI for vitamin D deficiency. Meta-regression and subgroup analyses were performed on latitude, body mass index, and assay method.

Results

A total of 21 studies, including 4,818 COPD patients and 7,175 controls, were included. Meta-analysis showed that lower serum vitamin D levels were found in COPD patients than in controls (SMD: −0.69, 95% CI: −1.00, −0.38, P<0.001), especially in severe COPD (SMD: −0.87, 95% CI: −1.51, −0.22, P=0.001) and COPD exacerbation (SMD: −0.43, 95% CI: −0.70, −0.15, P=0.002). Vitamin D deficiency was associated with increased risk of COPD (OR: 1.77, 95% CI: 1.18, 2.64, P=0.006) and with COPD severity (OR: 2.83, 95% CI: 2.00, 4.00, P<0.001) but not with COPD exacerbation (OR: 1.17, 95% CI: 0.86, 1.59, P=0.326). Assay methods had significant influence on the heterogeneity of vitamin D deficiency and COPD risk.

Conclusion

Serum vitamin D levels were inversely associated with COPD risk, severity, and exacerbation. Vitamin D deficiency is associated with increased risk of COPD and severe COPD but not with COPD exacerbation. It is worth considering assay methods in the heterogeneity sources analysis of association between vitamin D deficiency and COPD.

Relationship between vitamin D-binding protein polymorphisms and blood vitamin D level in Korean patients with COPD

Background

In chronic obstructive pulmonary disease (COPD), the blood vitamin D3 level is generally low, and genetic polymorphisms of vitamin D-binding protein encoded by the GC gene are associated with COPD development. In this study, we examined the relationship between GC polymorphisms and plasma vitamin D3 level in Korean patients with COPD.

Methods

The study included 175 COPD patients from the Korean Obstructive Lung Disease Cohort. Multivariate analysis was conducted with adjustment for age, body mass index (BMI), lung function, smoking status, smoking amount, and seasonal variation in blood vitamin D level. Vitamin D deficiency was defined as a plasma 25-hydroxyvitamin D₃ level lower than 20 ng/mL.

Results

The mean plasma vitamin D3 level was 17.5 ng/mL. The GC1F variant (44.3%) and genotype 1F-2 (27.4%) were the most common. The plasma vitamin D3 level was lower in patients with the GC2 variant (estimated =−3.73 ng/mL) and higher in those with genotype 1F-1S (estimated =4.08 ng/mL). The GC2 variant was a significant risk factor for vitamin D deficiency (odds ratio =2.41). Among COPD clinical parameters, vitamin D deficiency was associated with a lower ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC) regardless of GC polymorphisms. FEV₁/FVC was higher in patients with genotype 1F-1F (estimated =3.61%) and lower in those with genotype 1F-2 (estimated =−3.31%). The 6-minute walking distance was shorter for patients with the GC1F variant (estimated =−38.91 m) and longer for those with the GC2 variant (estimated =26.98 m). The emphysema index was higher for patients with the GC1S variant (estimated =6.56%) and genotype 1F-1S (estimated =9.86%), regardless of the vitamin D level.

Conclusion

The GC2 variant is a risk factor for vitamin D deficiency, and genotype 1F-1S is a protective factor against vitamin D deficiency. GC polymorphisms and vitamin D deficiency correlate with clinical outcomes for Korean patients with COPD.

A review of Vitamin D effects on common respiratory diseases: Asthma, chronic obstructive pulmonary disease, and tuberculosis

Despite the classic role of Vitamin D in skeletal health, new aspects of Vitamin D have been discovered in tissues and organs other than bones. Epidemiological and observational studies demonstrate a link between Vitamin D deficiency and risk of developing respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and tuberculosis (TB). To review the literature, we searched the terms "Vitamin D" (using the set operator) and "asthma," "COPD" and "TB" in electronic databases, including PubMed/MEDLINE, Scopus, and Google Scholar until July 2015. Non-English articles or articles with unavailable full text were excluded. Both in vivo and in vitro studies were included. All the reviewed articles state that Vitamin D deficiency is very common among patients with respiratory diseases. The present data regarding Vitamin D and asthma is still controversial, but data about COPD and TB are more encouraging. The relevant studies have been conducted in different populations therefore it is not particularly possible to compare the data due to genetic variations. In order to point out a role for Vitamin D, large clinical trials with Vitamin D deficient subjects and sufficient Vitamin D supplementation are needed.

Vitamin D Deficiency and Insufficiency in Hospitalized COPD Patients

Introduction

31–77% of patients with COPD have vitamin D deficiency and insufficiency, with results being highly variable between studies. Vitamin D may also correlate with disease characteristics.

Aim

To find out the prevalence of vitamin D deficiency and insufficiency in patients with COPD admitted for exacerbation and a risk factors for lower vitamin D levels among comorbidities and COPD characteristics.

Methods

152 patients were studied for vitamin D serum levels (25(OH)D). All of them were also assessed for diabetes mellitus (DM) and metabolic syndrome (MS). Data were gathered also for smoking status and exacerbations in last year. All patients completed CAT and mMRC questionnaires and underwent spirometry.

Results

A total of 83,6% of patients have reduced levels of vitamin D. 42,8% (65/152) have vitamin D insufficiency (defined as 25–50 nmol/L) and 40,8% (62/152) have vitamin D deficiency (<25 nmol/L). The mean level of 25(OH)D for all patients is 31,97 nmol/L (95%CI 29,12–34,68). Vitamin D deficiency and insufficiency are more prevalent in females vs. males (97,7 vs 77,8%; p = 0.003). The prevalence and severity of vitamin D deficiency and insufficiency in this study is significantly higher when compared to an unselected Bulgarian population (prevalence 75,8%; mean level 38,75 nmol/L). Vitamin D levels correlate with quality of life (measured by the mMRC scale) and lung function (FVC, FEV1, FEV6, FEF2575, FEV3, but not with FEV1/FVC ratio and PEF), it does not correlate with the presence of arterial hypertension, DM, MS and number of moderate, severe and total exacerbations. Vitamin D deficiency is a risk factor for longer hospital stay.

Conclusions

The patients with COPD admitted for exacerbation are a risk group for vitamin D deficiency and insufficiency, which is associated with worse disease characteristics.

Lung function, 25-hydroxyvitamin D concentrations and mortality in US adults

OBJECTIVE

To explore the associations between serum concentrations of vitamin D (25(OH)D) and all-cause mortality among US adults defined by lung function (LF) status, particularly among adults with obstructive LF (OLF).

METHODS

Data from 10,795 adults aged 20-79 years (685 with restrictive LF (RLF) and 1309 with OLF) who participated in the Third National Health and Nutrition Examination Survey (1988-1994), had a spirometric examination, and were followed through 2006 were included.

RESULTS

During 14.2 years of follow-up, 1792 participants died. Mean adjusted concentrations of 25(OH)D were 75.0 nmol/l (s.e. 0.7) for adults with normal LF (NLF), 70.4 nmol/l (s.e. 1.8) for adults with RLF, 75.5 nmol/l (s.e. 1.5) for adults with mild obstruction and 71.0 nmol/l (s.e. 1.9) among adults with moderate or worse obstruction (P=0.030). After adjustment for sociodemographic factors, lifestyle factors, clinical variables and prevalent chronic conditions, a concentration of <25 nmol/l compared with ⩾ 75 nmol//l was associated with mortality only among adults with NLF (hazard ratio (HR) 1.76; 95% confidence interval (CI) 1.03, 3.00). Among participants with OLF, adjusted HRs were 0.65 (95% CI 0.29, 1.48), 1.21 (95% CI 0.89, 1.66) and 0.97 (95% CI 0.78, 1.19) among those with concentrations <25, 25-<50 and 50-<75 nmol/l, respectively.

CONCLUSIONS

Baseline concentrations of 25(OH)D did not significantly predict mortality among US adults with impaired LF.

Relationship of vitamin D status with lung function and exercise capacity in COPD

BACKGROUND AND OBJECTIVE

The relationship between blood vitamin D level and clinical parameters in patients with chronic obstructive pulmonary disease (COPD) has been reported with conflicting results. We explored the effects of vitamin D on clinical characteristics of patients with COPD in Korea.

METHODS

The study population comprised 193 patients with COPD from Korean Obstructive Lung Disease Cohort. The plasma level of 25-OH vitamin D3 (25-OH-VitD3) was measured every year along with various clinical parameters such as lung function, 6-min walking (6MW) distance, quality of life, exacerbations and emphysema index. Generalized estimating equations and linear mixed model were used for statistical analysis.

RESULTS

Of the 193 patients, 12 (6.2%), 28 (14.5%) and 153 (79.3%) were categorized into normal, insufficiency and deficiency groups. Clustered analysis showed that the plasma 25-OH-VitD3 level was associated with the post-bronchodilator ratio of force expiratory volume in 1 s/forced vital capacity (FEV1 /FVC) (estimated = 0.001; P = 0.022). The vitamin D deficiency group showed lower FEV1 (estimated = -0.129, P = 0.043), FEV1 % predicted (estimated = -4.994, P = 0.029) and FEV1 /FVC ratio (estimated = -0.048, P = 0.001) than did the non-deficiency group. The 6MW distance tended to be shorter in deficiency group (estimated = -17.26, P = 0.069) than in non-deficiency group. Quality of life, exacerbation and emphysema index were not associated with plasma 25-OH-VitD3 level.

CONCLUSIONS

We demonstrated a high prevalence of vitamin D deficiency in Korean patients with COPD and a significant relationship between vitamin D deficiency and airflow limitation. The exercise capacity tended to be decreased in the vitamin D deficiency group.

Vitamin D, vitamin D binding protein, and longitudinal outcomes in COPD

Background

Associations between Vitamin D₃ [25(OH)D], vitamin D binding protein (VDBP) and chronic obstructive pulmonary disease (COPD) are previously reported. We aimed to further investigate these associations on longitudinal outcomes.

Methods

426 COPD patients from western Norway, GOLD stage II-IV, aged 40–76, were followed every six-month from 2006 through 2009 with spirometry, bioelectrical impedance measurements and registration of exacerbation frequency. Serum 25(OH)D and VDBP levels were determined at study-entry by high-performance liquid chromatography coupled with mass spectrometry and enzyme immunoassays respectively. Yearly change in lung function and body composition was assessed by generalized estimating equations (GEE), yearly exacerbation rate by negative binomial regression models, and 5 years all-cause mortality by Cox proportional-hazard regression.

Results

1/3 of the patients had vitamin D deficiency (<20ng/mL) and a greater decline in both FEV1 and FVC, compared to patients with normal levels; for FEV1 this difference only reached statistical significance in the 28 patients with the lowest levels (<10ng/mL, p = 0.01). Neither 25(OH)D nor VDBP levels predicted exacerbation rate, change in fat free mass index or risk of death.

Conclusion

Severe vitamin D deficiency may affect decline in lung function parameters in COPD. Neither 25(OH)D nor VDBP levels did otherwise predict markers of disease progression.

Does low vitamin D amplify the association of COPD with total and cardiovascular disease mortality?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has been shown to be associated with lower levels of vitamin D, and the latter has been associated with total and cardiovascular disease (CVD) mortality.

HYPOTHESIS

We hypothesized that lower vitamin D levels will further enhance the association of COPD and its severity with total and CVD mortality.

METHODS

We studied 7746 US adults age ≥40 years without known CVD (mean age, 59.8 years) and followed up through 2006 (8.2 ± 2.5 years) for total and CVD mortality. Serum 25-hydroxyvitamin D levels were categorized as tertiles: first tertile, <50.9 nm/L; second tertile, 50.9 to 73.6 nm/L; and third tertile, >73.6 nm/L. Severity of COPD was classified on the basis of forced expiratory volume per second (FEV1 ): mild COPD (FEV1 ≥80%) and moderate or severe COPD (FEV1 <80%), and requires a FEV1 /forced vital capacity ratio <70%. With Cox regression, we examined the hazard ratio (HR) and 95% confidence interval (CI) for total and CVD mortality according to COPD/vitamin D category, using those with no COPD in the first tertile of vitamin D as the reference group.

RESULTS

From Cox regression, unadjusted HRs increased successively with increasing COPD severity and decreasing vitamin D group to 4.5 (95% CI: 3.3-6.1) for total and 3.4 (95% CI: 2.2-5.3) for CVD mortality among those with moderate/severe COPD who were in the first tertile of vitamin D. After adjustment for age, sex, ethnicity, and other risk factors, these associations were attenuated but remained increased.

CONCLUSIONS

Lower levels of vitamin D may be associated with further increases in total and CVD mortality associated with COPD; however, age and cardiovascular risk factors appear to explain much of this association.

Vitamin D status and chronic obstructive pulmonary disease: a prospective general population study

OBJECTIVES

Vitamin D deficiency is common among persons with chronic obstructive pulmonary disease (COPD). Whether vitamin D affects the development and deterioration of COPD or is a consequence of the disease lacks clarity. We investigated the association between vitamin D status and prevalent and incident COPD in the general population.

METHODS

We included a total of 12,041 individuals from three general population studies conducted in 1993-94, 1999-2001, and 2006-2008, respectively, with vitamin D measurements. Information on COPD was obtained from the Danish National Patient Register and The Danish Registry of Causes of Death.

RESULTS

There were 85 prevalent and 463 incident cases of COPD (median follow-up 9.7 years). We found a statistically significant inverse association between vitamin D status and prevalent COPD with odds ratio = 0.89 (95% confidence interval, CI: 0.79, 1.0), but no statistically significant association with incident COPD with a hazard ratio = 0.98 (95% CI: 0.94, 1.0), respectively, per 10 nmol/l higher vitamin D status, when adjusted for possible confounders.

CONCLUSIONS

We found a statistically significant inverse cross-sectional association between vitamin D status and COPD, but no association between vitamin D status and incident COPD.

Prognostic value of C-reactive protein, leukocytes, and vitamin d in severe chronic obstructive pulmonary disease

Inflammatory biomarkers predict mortality and hospitalisation in chronic obstructive pulmonary disease (COPD). Yet, it remains uncertain if biomarkers in addition to reflecting disease severity add new prognostic information on severe COPD. We investigated if leukocytes, C-reactive protein (CRP), and vitamin D were independent predictors of mortality and hospitalisation after adjusting for disease severity with an integrative index, the i-BODE index. In total, 423 patients participating in a pulmonary rehabilitation programme, with a mean value of FEV₁ of 38% of predicted, were included. Mean followup was 45 months. During the follow-up period, 149 deaths (35%) were observed and 330 patients (78.0%) had at least one acute hospitalisation; 244 patients (57.7%) had at least one hospitalisation due to an exacerbation of COPD. In the analysis (Cox proportional hazards model) fully adjusted for age, sex, and i-BODE index, the hazard ratio for 1 mg/L increase in CRP was 1.02 (P = 0.003) and for 1 × 10⁹/L increase in leukocytes was 1.43 (P = 0.03). Only leukocyte count was significantly associated with hospitalisation. Vitamin D was neither associated with mortality nor hospitalisation. Leukocytes and CRP add little information on prognosis and vitamin D does not seem to be a useful biomarker in severe COPD in a clinical setting.

The role of vitamin D in chronic obstructive pulmonary disease, asthma and other respiratory diseases

There has been growing interest in recent years in the extraosseous effects of vitamin D. In this article, we review the physiology of vitamin D, the physiopathological effects associated with vitamin D deficit and the available evidence on its etiopathogenic role in respiratory diseases. Given the pleiotropic actions of vitamin D, it is biologically plausible that the deficit of this vitamin could play a pathogenic role of in the development of various respiratory diseases. However, the many epidemiological studies that have shown an association between low vitamin D levels and a higher risk of developing various respiratory diseases or a poorer prognosis if they do appear, were unable to show causality. Post-hoc analyses of some clinical trials, particularly in chronic obstructive pulmonary disease (COPD) and asthma, appear to suggest that some patient subtypes may benefit from correction of a vitamin D deficit. In this respect, it would be interesting to determine if the interindividual differences found in the effect of vitamin D deficit and responses to correcting this deficit could be explained by the genetic variants involved in vitamin D metabolism. Ultimately, only appropriately designed clinical trials will determine whether 25-OHD supplements can prevent or improve the course of the various respiratory diseases in which an epidemiological association between prognosis and vitamin D deficit has been described.

Vitamin D and chronic obstructive pulmonary disease: hype or reality?

Abundant laboratory findings show the important role vitamin D has in the innate and adaptive immune system. In human beings, observational studies have associated vitamin D deficiency with an increased risk for different inflammatory, infectious, and autoimmune diseases. With regard to chronic obstructive pulmonary disease (COPD), conflicting data have been reported. Most epidemiological studies have been restricted by their design, and larger longitudinal studies of population-based samples and of cohorts with COPD are warranted. An alternative explanation for the discordant results in COPD might be related to the complexity of the intracellular vitamin D signalling pathway, which is not shown in systemic levels of the precursor 25-hydroxyvitamin D. For COPD in particular, we speculate that local downregulation of vitamin D signalling from and beyond the receptor might clarify why pro-inflammatory processes in the airways are not or are insufficiently countered by vitamin D-dependent control mechanisms. In a disease already characterised by glucocorticoid resistance, the potential activation and reactivation of an intrinsic comprehensive system of immune control should attract more attention to design appropriate interventions with promising therapeutic potential.