Body mass index and the risk of COPD

The contribution of estimated dead space fraction to mortality prediction in patients with chronic obstructive pulmonary disease-a new proposal

Background

Mortality due to chronic obstructive pulmonary disease (COPD) is increasing. However, dead space fractions at rest (VD/VTrest) and peak exercise (VD/VTpeak) and variables affecting survival have not been evaluated. This study aimed to investigate these issues.

Methods

This retrospective observational cohort study was conducted from 2010-2020. Patients with COPD who smoked, met the Global Initiatives for Chronic Lung Diseases (GOLD) criteria, had available demographic, complete lung function test (CLFT), medication, acute exacerbation of COPD (AECOPD), Charlson Comorbidity Index, and survival data were enrolled. VD/VTrest and VD/VTpeak were estimated (estVD/VTrest and estVD/VTpeak). Univariate and multivariable Cox regression with stepwise variable selection were performed to estimate hazard ratios of all-cause mortality.

Results

Overall, 14,910 patients with COPD were obtained from the hospital database, and 456 were analyzed after excluding those without CLFT or meeting the lung function criteria during the follow-up period (median (IQR) 597 (331-934.5) days). Of the 456 subjects, 81% had GOLD stages 2 and 3, highly elevated dead space fractions, mild air-trapping and diffusion impairment. The hospitalized AECOPD rate was 0.60 ± 2.84/person/year. Forty-eight subjects (10.5%) died, including 30 with advanced cancer. The incidence density of death was 6.03 per 100 person-years. The crude risk factors for mortality were elevated estVD/VTrest, estVD/VTpeak, ≥2 hospitalizations for AECOPD, advanced age, body mass index (BMI) <18.5 kg/m2, and cancer (hazard ratios (95% C.I.) from 1.03 [1.00-1.06] to 5.45 [3.04-9.79]). The protective factors were high peak expiratory flow%, adjusted diffusing capacity%, alveolar volume%, and BMI 24-26.9 kg/m2. In stepwise Cox regression analysis, after adjusting for all selected factors except cancer, estVD/VTrest and BMI <18.5 kg/m2 were risk factors, whereas BMI 24-26.9 kg/m2 was protective. Cancer was the main cause of all-cause mortality in this study; however, estVD/VTrest and BMI were independent prognostic factors for COPD after excluding cancer.

Conclusions

The predictive formula for dead space fraction enables the estimation of VD/VTrest, and the mortality probability formula facilitates the estimation of COPD mortality. However, the clinical implications should be approached with caution until these formulas have been validated.

From pre-COPD to COPD: a Simple, Low cost and easy to IMplement (SLIM) risk calculator

BACKGROUND

The lifetime risk of developing clinical COPD among smokers ranges from 13% to 22%. Identifying at-risk individuals who will develop overt disease in a reasonable timeframe may allow for early intervention. We hypothesised that readily available clinical and physiological variables could help identify ever-smokers at higher risk of developing chronic airflow limitation (CAL).

METHODS

Among 2273 Lovelace Smokers' Cohort (LSC) participants, we included 677 (mean age 54 years) with normal spirometry at baseline and a minimum of three spirometries, each 1 year apart. Repeated spirometric measurements were used to determine incident CAL. Using logistic regression, demographics, anthropometrics, smoking history, modified Medical Research Council dyspnoea scale, St George's Respiratory Questionnaire, comorbidities and spirometry, we related variables obtained at baseline to incident CAL as defined by the Global Initiative for Chronic Obstructive Lung Disease and lower limit of normal criteria. The predictive model derived from the LSC was validated in subjects from the COPDGene study.

RESULTS

Over 6.3 years, the incidence of CAL was 26 cases per 1000 person-years. The strongest independent predictors were forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.75, having smoked ≥30 pack-years, body mass index (BMI) ≤25 kg·m2 and symptoms of chronic bronchitis. Having all four predictors increased the risk of developing CAL over 6 years to 85% (area under the receiver operating characteristic curve (AUC ROC) 0.84, 95% CI 0.81-0.89). The prediction model showed similar results when applied to subjects in the COPDGene study with a follow-up period of 10 years (AUC ROC 0.77, 95% CI 0.72-0.81).

CONCLUSION

In middle-aged ever-smokers, a simple predictive model with FEV1/FVC, smoking history, BMI and chronic bronchitis helps identify subjects at high risk of developing CAL.

Association between appendicular lean mass and chronic obstructive pulmonary disease: epidemiological cross-sectional study and bidirectional Mendelian randomization analysis

Background

The association of BMI with COPD, and sarcopenia in COPD have been both confirmed by several studies, but research on the relationship and causality of body lean mass and the risk of chronic obstructive pulmonary disease (COPD) remains to be discovered. The purpose of this study was to explore the association between lean mass and COPD risk as well as to further examine the causal relationship in the findings.

Methods

Three thousand four hundred fifty-nine participants from NHANES 2013-2018 were included in the epidemiological cross-sectional study to assess the association between relative lean mass and COPD by restricted spline analysis (RCS) and weighted multiple logistic regression. Furthermore, to verify the causality between lean mass and COPD, a two-sample Mendelian randomization (MR) with inverse variance weighting (IVW) method was used to analyze GWAS data from European ancestry. Genetic data from the United Kindom Biobank for appendicular lean mass (450,243 cases) and lung function (FEV₁/FVC) (400,102 cases) together with the FinnGen platform for COPD (6,915 cases and 186,723 controls) were used for MR.

Results

Weighted multiple logistic regression showed a significant correlation between relative appendicular lean mass and COPD after adjusting for confounders (OR = 0.985, 95% CI: 0.975-0.995). Compared to the lower mass (155.3-254.7) g/kg, the high mass (317.0-408.5) g/kg of appendicular lean apparently decreases the risk of COPD (OR = 0.214, 95% CI: 0.060-0.767). Besides, in the analysis of MR, there was a forward causality between appendicular lean mass and COPD (IVW: OR = 0.803; 95%CI: 0.680-0.949; p = 0.01), with a weak trend of causality to lung function.

Conclusion

Our study not only found an inverse association between appendicular lean mass and COPD but also supported a unidirectional causality. This provided possible evidence for further identification of people at risk for COPD and prevention of COPD based on limb muscle exercise and nutritional supplementation to maintain skeletal muscle mass.

CT pectoralis muscle area is associated with DXA lean mass and correlates with emphysema progression in a tobacco-exposed cohort

INTRODUCTION

Muscle loss is an important extrapulmonary manifestation of COPD. Dual energy X-ray absorptiometry (DXA) is the method of choice for body composition measurement but is not widely used for muscle mass evaluation. The pectoralis muscle area (PMA) is quantifiable by CT and predicts cross-sectional COPD-related morbidity. There are no studies that compare PMA with DXA measures or that evaluate longitudinal relationships between PMA and lung disease progression.

METHODS

Participants from our longitudinal tobacco-exposed cohort had baseline and 6-year chest CT (n=259) and DXA (n=164) data. Emphysema was quantified by CT density histogram parenchymal scoring using the 15th percentile technique. Fat-free mass index (FFMI) and appendicular skeletal mass index (ASMI) were calculated from DXA measurements. Linear regression model relationships were reported using standardised coefficient (β) with 95% CI.

RESULTS

PMA was more strongly associated with DXA measures than with body mass index (BMI) in both cross-sectional (FFMI: β=0.76 (95% CI 0.65 to 0.86), p<0.001; ASMI: β=0.76 (95% CI 0.66 to 0.86), p<0.001; BMI: β=0.36 (95% CI 0.25 to 0.47), p<0.001) and longitudinal (ΔFFMI: β=0.43 (95% CI 0.28 to 0.57), p<0.001; ΔASMI: β=0.42 (95% CI 0.27 to 0.57), p<0.001; ΔBMI: β=0.34 (95% CI 0.22 to 0.46), p<0.001) models. Six-year change in PMA was associated with 6-year change in emphysema (β=0.39 (95% CI 0.23 to 0.56), p<0.001) but not with 6-year change in airflow obstruction.

CONCLUSIONS

PMA is an accessible measure of muscle mass and may serve as a useful clinical surrogate for assessing skeletal muscle loss in smokers. Decreased PMA correlated with emphysema progression but not lung function decline, suggesting a difference in the pathophysiology driving emphysema, airflow obstruction and comorbidity risk.

Nonadherence to health promotion depending on chronic obstructive pulmonary disease severity

BACKGROUND

Nonadherence to recommended health behaviors reportedly correlates with the prevalence and health outcomes of COPD, but the factors contributing to multiple health promotions are not well understood.

OBJECTIVE

To examine the factors associated with nonadherence to health behaviors, specifically focusing on COPD severity.

METHODS

We conducted a secondary data analysis with data from the 2016-2019 Korea National Health and Nutrition Examination Survey. The analyzed data were from 1,627 individuals aged over 40 years who had a FEV1/FVC ratio < 70% measured via spirometer. In this study, nonadherence to health behaviors is the sum of seven health-promoting behaviors in terms of smoking cessation, alcohol abstinence, regular exercise, weight control, recommended sleep time, influenza vaccination, and medical check-up.

RESULTS

COPD patients' nonadherence to health behaviors was significantly associated with comorbidity (p=0.017), stress (p=0.002), and COPD severity (moderate, severe; p=0.010, p=0.039, respectively). In addition, the moderate and severe COPD groups showed a higher nonadherence rate than the mild COPD group. Specifically, nonadherence to weight control was the most significantly different behavior according to COPD severity levels, based on the GOLD classification of airflow limitation.

CONCLUSION

Our study findings support that those with higher levels of stress, comorbidities, and severe disease conditions are less likely to adhere to health behaviors. Thus, healthcare providers and policymakers should provide tailored approaches according to COPD severity to educate and support appropriate health behaviors for individuals with COPD.

Exosomes derived from adipose-derived stem cells alleviate cigarette smoke-induced lung inflammation and injury by inhibiting alveolar macrophages pyroptosis

Background

Chronic obstructive pulmonary disease (COPD) is a frequently encountered disease condition in clinical practice mainly caused by cigarette smoke (CS). The aim of this study was to investigate the protective roles of human adipose-derived stem cells-derived exosomes (ADSCs-Exo) in CS-induced lung inflammation and injury and explore the underlying mechanism by discovering the effects of ADSCs-Exo on alveolar macrophages (AMs) pyroptosis.

Methods

ADSCs were isolated from human adipose tissues harvested from three healthy donors, and then ADSCs-Exo were isolated. In vivo, 24 age-matched male C57BL/6 mice were exposed to CS for 4 weeks, followed by intratracheal administration of ADSCs-Exo or phosphate buffered saline. In vitro, MH-S cells, derived from mouse AMs, were stimulated by 2% CS extract (CSE) for 24 h, followed by the treatment of ADSCs-Exo or phosphate buffered saline. Pulmonary inflammation was analyzed by detecting pro-inflammatory cells and mediators in the bronchoalveolar lavage fluid. Lung histology was assessed by hematoxylin and eosin staining. Mucus production was determined by Alcian blue-periodic acid-Schiff staining. The profile of AMs pyroptosis was evaluated by detecting the levels of pyroptosis-indicated proteins. The inflammatory response in AMs and the phagocytic activity of AMs were also investigated.

Results

In mice exposed to CS, the levels of pro-inflammatory cells and mediators were significantly increased, mucus production was markedly increased and lung architecture was obviously disrupted. AMs pyroptosis was elevated and AMs phagocytosis was inhibited. However, the administration of ADSCs-Exo greatly reversed these alterations caused by CS exposure. Consistently, in MH-S cells with CSE-induced properties modelling those found in COPD, the cellular inflammatory response was elevated, the pyroptotic activity was upregulated while the phagocytosis was decreased. Nonetheless, these abnormalities were remarkably alleviated by the treatment of ADSCs-Exo.

Conclusions

ADSCs-Exo effectively attenuate CS-induced airway mucus overproduction, lung inflammation and injury by inhibiting AMs pyroptosis. Therefore, hADSCs-Exo may be a promising cell-free therapeutic candidate for CS-induced lung inflammation and injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01926-w.

Body mass index across adulthood and the development of airflow obstruction and emphysema

Background

Low body mass index (BMI) is associated with COPD, but temporal relationships between airflow obstruction (AO) development and emphysematous change are unclear. We investigated longitudinal changes in BMI, AO, and lung density throughout adulthood using data from the Framingham Offspring Cohort (FOC).

Methods

BMI trajectories were modelled throughout adulthood in 4587 FOC participants from Exam 2 (mean age = 44), through Exam 9 (mean age = 71), in AO participants and non-AO participants (AO n = 1036), determined by spirometry, using fractional polynomial growth curves. This process was repeated for low lung density (LLD) and non LLD participants (LLD n = 225) determined by Computed Tomography. Spirometry decline was compared separately between tertiles of BMI in those aged <40 years and associations between fat and lean mass (measured using Dual Energy X-ray Absorptiometry, DEXA) and development of AO and LLD were also assessed. Additional analyses were performed with adjustment for smoking volume.

Results

The BMI trajectory from 30 years of age was visually lower in the AO group than both non-AO smokers (non-<AO-S) and non-AO non-smokers (non-AO-N). Similarly, BMI trajectories were visually lower in participants with LLD throughout adulthood compared to normal lung density smokers and non-smokers. Differences remained after adjustment for smoking volume. The lowest BMI tertile in ages <40 years was associated with the steepest subsequent decline in FEV1/FVC ratio in both sexes.

Conclusion

Mean BMI is lower throughout adulthood in AO and LLD participants. Lower BMI is associated with a steeper decline in the ratio of FEV1/FVC. These findings suggest body mass may precede and potentially have a role in the development of COPD lung pathophysiology.

Low body mass is associated with reduced left ventricular mass in Chinese elderly with severe COPD

There is limited information on the association of body mass index (BMI) with left ventricular (LV) remodeling corresponding to severity of reduced lung function in patients with chronic obstructive pulmonary disease (COPD). Therefore, we investigated whether BMI is associated with cardiac atrial and ventricular dimensions according to severity of lung functional impairment in Chinese COPD elderly. A total of 563 hospitalized COPD patients with lung function impairment and 184 patients with non-COPD (aged 65–92 years) were collected retrospectively in a cross-sectional study in a university affiliated tertiary hospital in China. BMI and cardiac echocardiographic parameters were compared according to severity of lung functional impairment in COPD patients. BMI was 22.9 ± 3.9 kg/m² in COPD patients, 24.0 ± 4.1 kg/m² in non-COPD patients respectively. Reduced BMI, LV mass index, LV wall thickness and left atrial diameter, and dilated right ventricle (RV) existed in COPD patients with severe lung dysfunction as compared the COPD patients with mild to moderate lung functional reduction and non-COPD patients (P < 0.05), while there were no differences in BMI and echocardiographic parameters between the COPD patients with mild to moderate lung functional decline and non-COPD patients (P > 0.05). Logistic regression analysis showed that low BMI (BMI < 18.5 kg/m²) was correlated with reduced LV mass and wall thickness, dilated RV and reduced lung function in the COPD patients with severe lung dysfunction. In conclusion, this study demonstrates that lower BMI is associated not only with dilated RV and impaired pulmonary function, but also it is related to reduced LV mass in Asian COPD elderly with severe lung dysfunction.

COPD risk among older construction workers-Updated analyses 2020

BACKGROUND

A 2010 study of construction workers participating in medical screening programs at the Department of Energy (DOE) nuclear facilities demonstrated increased chronic obstructive pulmonary disease (COPD) risk. The current study of a larger worker cohort allowed for a more nuanced analysis of COPD risk, including for employment beginning after the mid-1990s.

METHODS

Study participants included 17,941 workers with demographic and smoking data and spirometry with a minimum of three recorded expiratory efforts and reproducibility of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁ ) of 0.2 L or less. COPD was defined as a FEV₁ /FVC ratio below the lower limit of normal using established prediction equations without use of bronchodilation. Stratified analyses explored COPD prevalence by demographic variables and trade. Logistic regression analyses assessed risks by trade and time periods of trade and DOE site work, controlling for age, gender, race/ethnicity, body mass index, and smoking.

RESULTS

Overall COPD prevalence was 13.4% and 67.4% of cases were classified as moderate to severe. Compared to nonconstruction workers, construction trade workers were at significantly increased risk of all COPD (OR = 1.34, 95% CI = 1.29-1.79) and even more so for severe COPD (OR = 1.61, 95% CI = 1.32-1.96). The highest risk trades were cement masons/bricklayers (OR = 2.36; 95% CI = 1.71-3.26) and roofers (OR = 2.22; 95% CI = 1.48-3.32). Risk among workers employed after 1995 was elevated but not statistically significant.

CONCLUSIONS

Construction workers are at increased COPD risk. Results support the prevention of both smoking and occupational exposures to reduce these risks. While the number of participants employed after 1995 was small, patterns of risk were consistent with findings in the overall cohort.

Association of Body Mass Index with Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

The association between body mass index (BMI) and chronic obstructive pulmonary disease (COPD) remains controversial. Therefore, a meta-analysis was conducted to further evaluate the relationship. A comprehensive literature search was performed in PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang databases to identify eligible articles until July 15, 2020. Random effect model (REM) was used to compute the pooled results with 95% confidence intervals (CIs). We conducted meta-regression and subgroup analysis to explore potential sources of heterogeneity. Publication bias was evaluated by funnel plots and Egger's test. Thirty articles with 1,578,449 participants were included in the meta-analysis. The pooled OR of COPD was 1.96 (95% CI: 1.78-2.17) for the underweight group, 0.80 (95% CI: 0.73-0.87) for overweight group, and 0.86 (95% CI: 0.73-1.02) for obesity group. After further excluding 5 studies of high between-study heterogeneity in sensitivity analysis, the pooled OR of COPD was 0.77 (95% CI: 0.68-0.86) for the obesity group. This meta-analysis indicated that BMI was associated with COPD. Specifically, underweight might increase the risk of COPD; overweight and obesity might reduce the risk of COPD.

Serum Levels of Gamma-Glutamyltransferase During Stable and Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Background

One of the most important factors in the pathogenesis of COPD (chronic obstructive pulmonary disease) is oxidative stress. GGT (gamma-glutamyltransferase) has been regarded as a novel marker of oxidative stress over the last few years. This study aimed to compare the serum levels of GGT during stable and acute exacerbations of COPD at a single center.

Material/Methods

The research included 117 patients with AECOPD (acute exacerbation of chronic obstructive pulmonary disease), 107 patients with stable COPD, and 112 control subjects. Serum GGT, spirometry function, and other clinical parameters (anthropometric and biochemical measurements) were evaluated and compared among the subjects.

Results

Serum GGT was elevated in patients with stable COPD in comparison to the control subjects. Its level was inversely related to lung function. It was also significantly higher in AECOPD patients compared to stable COPD patients. We also found that a GGT level of 21.2 IU/L displays a reliable diagnostic prediction of COPD and that a GGT level of 26.5 IU/L can be applied to predict the exacerbation of COPD.

Conclusions

Our research demonstrates that serum GGT level is inversely associated with pulmonary function and may serve as a biomarker during the progression of COPD. The monitoring of GGT values can be applied to evaluating COPD and its exacerbation risk.

Epidemiology and risk factors of chronic obstructive pulmonary disease in Suzhou: a population-based cross-sectional study

Background

The prevalence of chronic obstructive pulmonary disease (COPD) in Suzhou remains still unknown. The aim of this study was to quantify the disease burden and assess the risk factors of COPD.

Methods

This was a population-based, cross-sectional study of adults aged 40 years and older in Suzhou. A total of 4,864 adults were identified from June 2018 to December 2018 and 4,725 adults were finally recruited. Subjects underwent post-bronchodilator spirometry and were diagnosed according to the 2018 Global Initiative for Chronic Obstructive Lung Disease (GOLD).

Results

The data from 4,725 adults were ultimately included in the final analysis. The overall prevalence of COPD in subjects aged 40 and older was 12.4%, while it was 12.3% in men and 12.5% in women. Risk factors identified by multivariable logistic analysis were age (P<0.05, OR =2.29, 95% CI, 1.83–2.88) and underweight (BMI <18.5 kg/m²) (P<0.05, OR =1.57, 95% CI, 1.01–2.44). COPD patients also displayed weaker grip strength (P<0.001). Approximately half (50.7%) the COPD patients were asymptomatic, and compared with asymptomatic COPD patients, symptomatic COPD patients were older (69.5 vs. 67.2, P<0.05), smoked more frequently (12.1 vs. 7.1 pack year, P<0.05), had a more severe GOLD stage (stage I 27.0% vs. 39.4%, stage II 50.2% vs. 46.8%, stage III 17.0% vs. 11.1%, stage IV 5.8% vs. 2.7%, P<0.05), and a worse lung function index (FEV₁, FVC, PEF, FEF₂₅, FEF₅₀, FEF₇₅, FEF₂₅₇₅) (P<0.05).

Conclusions

COPD was found to be highly prevalent in adults aged 40 years and older in Suzhou. Age and underweight were major risk factors of COPD. Half of the COPD patients were asymptomatic, and displayed decreased lung function upon the onset of respiratory symptoms. Therefore, spirometry screening is essential for the early detection and management of COPD.

The Construction of Primary Screening Model and Discriminant Model for Chronic Obstructive Pulmonary Disease in Northeast China

Objective

The diagnosis of chronic obstructive pulmonary disease (COPD) is challenging, especially in the primary institution which lacks spirometer. To reduce the rate of COPD missed diagnoses in Northeast China, which has a higher prevalence of COPD, this study aimed to establish efficient primary screening and discriminant models of COPD in this region.

Patients and Methods

Subjects from Northeast China were enrolled from December 2017 to April 2019 from The First Hospital of China Medical University. Pulmonary function tests and questionnaire were given to all participants. Using illness or no illness as the goal for screening models and disease severity as the goal for discriminant models, multivariate linear regression, logical regression, linear discriminant analysis, K-nearest neighbor, decision tree and support vector machine were constructed through R language and Python software. After comparing effectiveness among them, the most optimal primary screening and discriminant models were established.

Results

Enrolled were 232 COPD patients (124 GOLD I–II and 108 GOLD III–IV) and 218 normal controls. Eight primary screening models were established. The optimal model was Y = −1.2562–0.3891X₄ (education level) + 1.7996X₅ (dyspnea) + 0.5102X₆ (cooking fuel grade) + 1.498X₇ (smoking index) + 0.8077X₉ (family history)-0.5552X₁₁ (BMI) + 0.538X₁₃ (cough with sputum) + 2.0328X₁₄ (wheezing) + 1.3378X₁₆ (farmers) + 0.8187X₁₇ (mother’s smoking exposure history during pregnancy)-0.389X₁₈ (kitchen ventilation) + 0.6888X₁₉ (childhood heating). Six discriminant models were established. The optimal model was decision tree (the optimal variables: dyspnea (x₅), cooking fuel grade (x₆), second-hand smoking index (x₈), BMI (x₁₁), cough (x₁₂), cough with sputum (x₁₃), wheezing (x₁₄), farmer (x₁₆), kitchen ventilation (x₁₈), and childhood heating (x₁₉)). The code was established to combine the discriminant model with computer technology.

Conclusion

Many factors were related to COPD in Northeast China. Stepwise logistic regression and decision tree were the optimal screening and discriminant models for COPD in this region.

Somatotypes trajectories during adulthood and their association with COPD phenotypes

RATIONALE

Chronic obstructive pulmonary disease (COPD) comprises distinct phenotypes, all characterised by airflow limitation.

OBJECTIVES

We hypothesised that somatotype changes - as a surrogate of adiposity - from early adulthood follow different trajectories to reach distinct phenotypes.

METHODS

Using the validated Stunkard's Pictogram, 356 COPD patients chose the somatotype that best reflects their current body build and those at ages 18, 30, 40 and 50 years. An unbiased group-based trajectory modelling was used to determine somatotype trajectories. We then compared the current COPD-related clinical and phenotypic characteristics of subjects belonging to each trajectory.

MEASUREMENTS AND MAIN RESULTS

At 18 years of age, 88% of the participants described having a lean or medium somatotype (estimated body mass index (BMI) between 19 and 23 kg·m-2) while the other 12% a heavier somatotype (estimated BMI between 25 and 27 kg·m-2). From age 18 onwards, five distinct trajectories were observed. Four of them demonstrating a continuous increase in adiposity throughout adulthood with the exception of one, where the initial increase was followed by loss of adiposity after age 40. Patients with this trajectory were primarily females with low BMI and D LCO (diffusing capacity of the lung for carbon monoxide). A persistently lean trajectory was seen in 14% of the cohort. This group had significantly lower forced expiratory volume in 1 s (FEV1), D LCO, more emphysema and a worse BODE (BMI, airflow obstruction, dyspnoea and exercise capacity) score thus resembling the multiple organ loss of tissue (MOLT) phenotype.

CONCLUSIONS

COPD patients have distinct somatotype trajectories throughout adulthood. Those with the MOLT phenotype maintain a lean trajectory throughout life. Smoking subjects with this lean phenotype in early adulthood deserve particular attention as they seem to develop more severe COPD.

Endoscopic Lung Volume Reduction in Relation to Body Mass Index in Patients with Severe Heterogeneous Emphysema

BACKGROUND

In chronic obstructive pulmonary disease (COPD), body mass index (BMI) is significantly lower in the emphysema-dominant type. Endoscopic lung volume reduction (ELVR) is an innovative way of treating severe emphysema. However, the specific associations of low BMI values and outcomes of ELVR is not well-studied.

OBJECTIVES

We evaluated associations between initial BMI and changes in major outcomes after endobronchial valve (EBV) placement in patients with heterogeneous severe emphysema.

METHODS

In a retrospective cohort study, patients were divided into 2 groups based on their baseline BMI (higher BMI ≥21 kg/m2 [n = 18] and lower BMI <21 kg/m2 [n = 63]). Demographics, procedure data, pulmonary function test and 6-min-walk test (6MWT), dyspnea score (according to the modified Medical Research Council [mMRC] scale), BODE (BMI, airflow obstruction, dyspnea, exercise capacity) index, and complications were recorded. After 6 months, changes in variables (dWeight and dBMI) were recorded.

RESULTS

Comparing the 2 groups, we found the following: a dWeight of -2.34 kg and +3.39 kg (p value <0.01) and a dBMI of -0.74 and +1.99 kg/m2, in the higher BMI and lower BMI group, respectively (p value <0.01). Changes in forced expiratory volume <1 s (FEV1), 6MWT, mMRC score, and BODE index were not statistically significant. The most common complication was pneumothorax. The lower BMI group experienced more complications than the higher BMI group (40 vs. 24%).

CONCLUSION

Baseline BMI is relevant when selecting candidates for ELVR. Our results show that the COPD patients with a lower BMI gained a significant amount of weight, thus increasing their BMI after the procedure. The rate of complications was higher in the lower BMI group. These findings should alert physicians and encourage nutritional assessment in this population.

Use of the COPD Assessment Test (CAT) to screen for COPD in dairy farmers: AIRBAg study

OBJECTIVES

People at risk of chronic obstructive pulmonary disease (COPD) can benefit from appropriate medical management before severe symptoms appear. This study assesses the value of the COPD Assessment Test (CAT) questionnaire for screening dairy farmers, who tend to be slow or reluctant to seek health care.

METHODS

During the time period 2012-2017, 2089 randomly selected dairy farmers in Brittany (France) were invited to complete self-administered questionnaires (including the CAT) and to undergo an occupational health check-up using an electronic mini-spirometer and conventional spirometry. Those showing symptoms suggestive of COPD and/or a ratio FEV₁ /FEV₆ < 80% were sent to a pulmonologist for a further check-up, including spirometry with a reversibility test. Multivariate logistic models based on CAT scores and socio-demographic or work-related factors were developed to predict COPD.

RESULTS

The 1231 farmers who underwent the occupational health check-up included 1203 who met the inclusion/exclusion criteria. Pulmonologist identified 16 (1.3%) cases of COPD. A multivariate logistic regression model (covariates: CAT sum score, on-farm time, BMI, smoking status, free-stall mulching) provided an area under the receiver-operating characteristic curve (AUC) of 0.87 (95% CI: 0.75-0.98). Using a cut-off of 0.007 gave a sensitivity of 93.8% and a specificity of 62.4%. Another model that included CAT breathlessness and the same covariates performed marginally better (AUC = 0.88, 95% CI: 0.77-0.98).

CONCLUSION

Our predictive models can both benefit dairy farmers by providing early diagnosis and management of their COPD and avoid unnecessary, costly spirometry during the screening process.

Association between adiposity measures and COPD risk in Chinese adults

Bodyweight and fat distribution may be related to COPD risk. Limited prospective evidence linked COPD to abdominal adiposity. We investigated the association of body mass index (BMI) and measures of abdominal adiposity with COPD risk in a prospective cohort study.The China Kadoorie Biobank recruited participants aged 30-79 years from 10 areas across China. Anthropometric indexes were objectively measured at the baseline survey during 2004-2008. After exclusion of participants with prevalent COPD and major chronic diseases, 452 259 participants were included and followed-up until the end of 2016. We used Cox models to estimate adjusted hazard ratios relating adiposity to risk of COPD hospitalisation or death.Over an average of 10.1 years of follow-up, 10 739 COPD hospitalisation events and deaths were reported. Compared with subjects with normal BMI (18.5-<24.0 kg·m-2), underweight (BMI <18.5 kg·m-2) individuals had increased risk of COPD, with adjusted hazard ratio 1.78 (95% CI 1.66-1.89). Overweight (BMI 24.0-<28.0 kg·m-2) and obesity (BMI ≥28.0 kg·m-2) were not associated with an increased risk after adjustment for waist circumference. A higher waist circumference (≥85 cm for males and ≥80 cm for females) was positively associated with COPD risk after adjustment for BMI. Additionally, waist-to-hip ratio and waist-to-height ratio were positively related to COPD risk.Abdominal adiposity and underweight were risk factors for COPD in Chinese adults. Both BMI and measures of abdominal adiposity should be considered in the prevention of COPD.

Home-Based Multicomponent Intervention Increases Exercise Activity and Improves Body Mass Index: Results of a 5-Year Randomized Trial Among Individuals with Alpha-1 Antitrypsin Deficiency-Associated Lung Disease

Background

The Step Forward Study (SFS) was designed to increase exercise activity and improve body mass index (BMI) among individuals with alpha-1 antitrypsin deficiency (AATD)-associated lung disease.

Methods

The SFS is a randomized trial of an intensive distance intervention that was delivered via a series of mailings and teleconferences versus no additional intervention. All participants (n=500) were also enrolled in a disease management program designed for individuals with AATD-associated lung disease who have been prescribed augmentation therapy. The primary outcome was self-reported number of exercise minutes per week. The secondary outcome was BMI. Linear mixed model analyses were used to assess the difference in average weekly exercise minutes between the intervention arms over time. T-tests, signed rank and Wilcoxon rank-sum tests were used to evaluate changes in BMI between the intervention arms and within each BMI category.

Results

The study included 429 individuals with evaluable primary outcome data.There was a significant effect of intervention on exercise minutes over time (p=0.018). Participants in the intervention group reported an average of 167.14 minutes (standard deviation [SD]=10.68) of weekly exercise and those in the standard care group reported 148.31 minutes (SD=10.96). There was a significant difference in BMI change between the intervention (mean BMI decrease 0.74, SD=2.16) and the standard care group (mean BMI decrease 0.27, SD=1.63); p=0.0122.

Conclusion

Individuals who were randomly assigned to the intervention group reported more exercise activity and improvements in BMI over the course of this multicomponent intervention compared to individuals assigned to standard care.

Investigation of the Obesity Paradox in Chronic Obstructive Pulmonary Disease, According to Smoking Status, in the United States

An obesity paradox in chronic obstructive pulmonary disease (COPD), whereby overweight/obese individuals have improved survival, has been well-described. These studies have generally included smokers. It is unknown whether the paradox exists in individuals with COPD arising from factors other than smoking. Nonsmoking COPD is understudied yet represents some 25%-45% of the disease worldwide. To determine whether the obesity paradox differs between ever- and never-smokers with COPD, 1,723 adult participants with this condition were examined from 2 iterations of the National Health and Nutrition Examination Survey (1988-1994, 2007-2010), with mortality outcomes followed through December 2011. Using Cox proportional hazards models, adjusted for sociodemographic factors, lung function, and survey cycle, ever/never-smoking was found to modify the association between body mass index and hazard of death. Compared with normal-weight participants, overweight/obese participants had lower hazard of death among ever-smokers (for overweight, adjusted hazard ratio (aHR) = 0.56, 95% confidence interval (CI): 0.43, 0.74; for obesity, aHR = 0.66, 95% CI: 0.48, 0.92), but never-smokers did not (overweight, aHR = 1.41, 95% CI: 0.66, 3.03; obesity, aHR = 1.29, 95% CI: 0.48, 3.48). An obesity paradox appeared to be absent among never-smokers with COPD. This, to our knowledge, novel finding might be explained by pathophysiological differences between smoking-related and nonsmoking COPD or by smoking-associated methodological biases.

BMI is associated with FEV1 decline in chronic obstructive pulmonary disease: a meta-analysis of clinical trials

Background

There is considerable heterogeneity in the rate of lung function decline in chronic obstructive pulmonary disease (COPD), the determinants of which are largely unknown. Observational studies in COPD indicate that low body mass index (BMI) is associated with worse outcomes, and overweight/obesity has a protective effect – the so-called “obesity paradox”. We aimed to determine the relationship between BMI and the rate of FEV₁ decline in data from published clinical trials in COPD.

Methods

We performed a systematic review of the literature, and identified 5 randomized controlled trials reporting the association between BMI and FEV₁ decline. Four of these were included in the meta-analyses. We analyzed BMI in 4 categories: BMI-I (< 18.5 or <  20 kg/m²), BMI-II (18.5 or 20 to < 25 kg/m²), BMI-III (25 to < 29 or < 30 kg/m²) and BMI-IV (≥29 or ≥ 30 kg/m²). We then performed a meta-regression of all the estimates against the BMI category.

Results

The estimated rate of FEV₁ decline decreased with increasing BMI. Meta-regression of the estimates showed that BMI was significantly associated with the rate of FEV₁ decline (linear trend p = 1.21 × 10^− 5).

Conclusions

These novel findings support the obesity paradox in COPD: compared to normal BMI, low BMI is a risk factor for accelerated lung function decline, whilst high BMI has a protective effect. The relationship may be due to common but as-of-yet unknown causative factors; further investigation into which may reveal novel endotypes or targets for therapeutic intervention.

Low Body Mass Index Is Associated with Higher Odds of COPD and Lower Lung Function in Low- and Middle-Income Countries

The relationship of body mass index (BMI) with lung function and COPD has been previously described in several high-income settings. However, few studies have examined this relationship in resource-limited settings where being underweight is more common. We evaluated the association between BMI and lung function outcomes across 14 diverse low- and middle-income countries. We included data from 12,396 participants aged 35-95 years and used multivariable regressions to assess the relationship between BMI with either COPD and lung function while adjusting for known risk factors. An inflection point was observed at a BMI of 19.8 kg/m². Participants with BMI < 19.8 kg/m² had a 2.28 greater odds (95% CI 1.83-2.86) of having COPD and had a 0.21 (0.13-0.30) lower FEV₁ and 0.34 (0.27-0.41) lower FEV₁/FVC z-score compared to those with BMI ≥ 19.8 kg/m². The association with lung function remained even after excluding participants with COPD. Individuals with lower BMI were more likely to have COPD and had lower lung function compared to those in higher BMI. The association with lung function remained positive even after excluding participants with COPD, suggesting that being underweight may also play a role in having worse lung function.

Disease-Specific Comorbidity Clusters in COPD and Accelerated Aging

Background: Patients with chronic obstructive pulmonary disease (COPD) often suffer from multiple morbidities, which occur in clusters and are sometimes related to accelerated aging. This study aimed to assess the disease specificity of comorbidity clusters in COPD and their association with a biomarker of accelerated aging as a potential mechanistic factor. Methods: Body composition, metabolic, cardiovascular, musculoskeletal, and psychological morbidities were objectively evaluated in 208 COPD patients (age 62 ± 7 years, 58% males, FEV₁ 50 ± 16% predicted) and 200 non-COPD controls (age 61 ± 7 years, 45% males). Based on their presence and severity, the morbidities were clustered to generate distinct clusters in COPD and controls. Telomere length in circulating leukocytes was compared across the clusters. Results: (co)morbidities were more prevalent in COPD patients compared to controls (3.9 ± 1.7 vs. 2.4 ± 1.5, p < 0.05). A “Psychologic” and “Cachectic” cluster were only present in the COPD population. “Less (co)morbidity”, “Cardiovascular”, and “Metabolic” clusters were also observed in controls, although with less complexity. Telomere length was reduced in COPD patients, but did not differ between the (co)morbidity clusters in both populations. Conclusions: Two COPD-specific comorbidity clusters, a “Cachectic” and “Psychologic” cluster, were identified and warrant further studies regarding their development. Accelerated aging was present across various multimorbidity clusters in COPD.

Evaluation of alpha-1-antitrypsin levels in blood serum of patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a disease that causes obstructed air flow from the lungs. The disease also has a dramatic role in increasing rate of mortality and morbidity in recent years. Air pollution, long-term exposure to particulate matter and irritating gases, especially cigarette smoke, genetic inheritance which has an impact on the initial forced expiratory volume one in second (FEV1), and alpha-1-antitrypsin (AAT) deficiency are among common COPD risk factors. The objective of this study is to evaluate parameters and serum AAT levels in COPD patients.

MATERIALS AND METHODS

Having taken the approval of local ethical committee, this cross-sectional study was performed with adult patients diagnosed with COPD, whose serum AAT levels were measured through nephelometric analysis in Kars Harakani State Hospital where secondary health care is served. The study evaluated ATT levels in patients' serum in relation to their age, gender, body mass (BMI), exposure to cigarette smoke, FEV1 percentage, hospitalization in pulmonology or intensive care unit through a year, mortality status, white blood cell (WBC), c-reactive protein (CRP) and blood gases.

RESULTS

The average age of the 243 patients included in the study was 68.41±11.52 and 160 (65.8%) of them were male. The age and BMI of the female patients were higher. Of the all patients only a single patient's serum AAT level was below the reference value. AAT levels were similar in both genders irrespective of their being exposed to cigarette smoke or being discharged or being exitus at their first admission to hospital, being exitus in the first year of disease diagnose, and being hospitalized in intensive care unit. AAT levels were reasonably correlated with WBC and CRP in a positive way (p<0.001 r=0.289 for WBC; p<0.001, r=0.295 for CRP). AAT levels were seen to significantly increase along with COPD stages which go up with FEV1 percentages (p<0.001). CRP was watched to have increased to Stage III COPD (severe COPD). However, it was watched to have decreased in Stage IV (very severe COPD) (p =0.179).

CONCLUSION

In the study, AAT serum levels of COPD patients were examined. The levels and their relations in various parameters of the patients were evaluated.

Estimating prevalence of chronic obstructive pulmonary disease in the Southern Cone of Latin America: how different spirometric criteria may affect disease burden and health policies

Background

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide. The study aimed to determine and compare the prevalence of COPD in the general population aged 45-74 years old according to fixed ratio and lower limit of normal (LLN) thresholds in four cities in the Southern Cone of Latin America.

Methods

The Pulmonary Risk in South America (PRISA) study used a 4-stage stratified sampling method to select 5814 participants from 4 cities in the Southern Cone of Latin America (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay). Data on demographic information, medical history, risk factors, pre-bronchodilator and post-bronchodilator spirometry were obtained using a standard protocol. According to GOLD, COPD was defined as a post-bronchodilator ratio of forced expiratory volume in one second (FEV1) over forced vital capacity (FVC) less than 70%. The LLN threshold was defined as the lower fifth percentile for predicted FEV1/FVC, and was evaluated as an alternative COPD definition.

Results

Overall COPD prevalence was 9.3% (95% CI 8.4, 10.2%), and men had a higher prevalence [11.8% (95% CI 10.3, 13.3%)] than women [7.3% (95% CI 6.2, 8.3%)] with the fixed ratio. Overall COPD prevalence using LLN was 4.7% (95% CI 4.1, 5.3%), higher in men: 5.8% (95% CI 4.7, 6.8%) than women: 3.9% (95% CI 3.1, 4.7%). COPD prevalence was significantly higher among those who were older, had <high-school education and lower body-mass index, were cigarette smokers, and had self-reported history of asthma and tuberculosis.

Conclusions

First, COPD and its risk factors are highly prevalent in the general population of Argentina, Chile, and Uruguay. Second, the prevalence of COPD by LLN criterion was significantly lower with lesser degrees of severity compared to fixed ratio of FEV1/FVC. Implementing LLN criterion instead of fixed ratio of FEV1/FVC may reduce the risk of over-diagnosis of COPD, although further prognostic studies of COPD adverse outcomes should be conducted using both definitions. Third, these data suggest that national efforts on the prevention, treatment, and control of COPD should be a public health priority in the Southern Cone of Latin America.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0537-9) contains supplementary material, which is available to authorized users.

Prevalence and predictors associated with severe pulmonary hypertension in COPD

BACKGROUND

Pulmonary hypertension (PH) is one of the most common complications of COPD (chronic obstructive pulmonary disease), but its severe form is uncommon. Various factors play an important role in the occurrence and severity of pulmonary hypertension in patients.

METHODS

This cross-sectional study was performed on patients with COPD referred to an emergency department over a one-year period. The tests-including complete blood count (CBC) and arterial blood gas (ABG), pulmonary functional test (PFT) and echocardiography-were performed for all patients to measure mPAP (mean pulmonary artery pressure), ejection fraction (EF) and body mass index (BMI). The prevalence of severe pulmonary hypertension and its associated factors were investigated in these patients.

RESULTS

A total of 1078 patients was included in the study, of whom 628 (58.3%) were male and 450 (41.7%) were female. The mean age of the patients undergoing the study was 70.1±12.2. A total of 136 (13.7%) of them had mPAP (mm Hg)≥40mm Hg as severe pulmonary hypertension. Following multivariable analysis by using the backward conditional method, it was shown that seven variables had a significant correlation with severe PH.

CONCLUSIONS

The results showed that there is an independent correlation between hypoxia, hypopnea and compensatory metabolic alkalosis, polycythemia, left ventricular dysfunction, emaciation, and cachectic with severe pulmonary hypertension. The prevalence of severe PH in these patients was 13.7%.

Wellbeing and chronic lung disease incidence: The Survey of Health, Ageing and Retirement in Europe

BACKGROUND

Previous studies indicate that psychosocial factors can impact COPD prevalence. However, research into this association has predominantly focused on negative factors such as depression. The aim of this study was to examine whether high subjective wellbeing is associated with a lower risk of developing COPD.

METHODS

The sample consisted of 12,246 participants aged ≥50 years from the Survey of Health, Ageing and Retirement in Europe. We used Cox proportional hazards regression to examine the relationship between wellbeing (measured using the CASP-12) and incidence of COPD over a follow-up period of 9 years.

RESULTS

There was a significant association between wellbeing and COPD risk. In age-adjusted analyses, a standard deviation increase in CASP-12 score was associated with a reduced risk of COPD; hazard ratios (95% confidence intervals) for men and women were 0.67 (0.60-0.75) and 0.80 (0.73-0.87) respectively. After additional adjustment for demographic and health behaviour variables, this association remained significant for men but not for women: the fully-adjusted hazard ratios were 0.80 (0.70-0.91) and 0.91 (0.82-1.03) respectively.

CONCLUSIONS

Greater wellbeing is associated with a reduced risk of COPD, particularly in men. Future research is needed to establish whether gender reliably moderates this association.

Prevalence and risk factors of airflow limitation in a Mongolian population in Ulaanbaatar: Cross-sectional studies

The burden of chronic obstructive pulmonary disease (COPD) is expected to increase in the coming decades. In Ulaanbaatar, Mongolia, air pollution, which has been suggested to correlate with COPD, is a growing concern. However, the COPD prevalence in Ulaanbaatar is currently unknown. This study aims to estimate the prevalence of airflow limitation and investigate the association between airflow limitation and putative risk factors in the Mongolian population. Five cross-sectional studies were carried out in Ulaanbaatar. Administration of a self-completed questionnaire, body measurements, and medical examination including spirometry were performed in 746 subjects aged 40 to 79 years living in Ulaanbaatar. The age- and sex-standardized prevalence of airflow limitation in Ulaanbaatar varied widely from 4.0 to 10.9% depending on the criteria for asthma. Age, body mass index (BMI), and smoking habit were independent predictors for airflow limitation while residential area and household fuel type were not significant. In conclusion, prevalence of putative COPD was 10.0% when subjects with physician-diagnosed asthma were excluded from COPD. Older age, lower BMI, and current smoking status were putative risk factors for airflow limitation. This prevalence was consistent with reports from Asian countries.

SmokeHaz: Systematic Reviews and Meta-analyses of the Effects of Smoking on Respiratory Health

BACKGROUND

Smoking tobacco increases the risk of respiratory disease in adults and children, but communicating the magnitude of these effects in a scientific manner that is accessible and usable by the public and policymakers presents a challenge. We have therefore summarized scientific data on the impact of smoking on respiratory diseases to provide the content for a unique resource, SmokeHaz.

METHODS

We conducted systematic reviews and meta-analyses of longitudinal studies (published to 2013) identified from electronic databases, gray literature, and experts. Random effect meta-analyses were used to pool the findings.

RESULTS

We included 216 articles. Among adult smokers, we confirmed substantially increased risks of lung cancer (risk ratio (RR), 10.92; 95% CI, 8.28-14.40; 34 studies), COPD (RR, 4.01; 95% CI, 3.18-5.05; 22 studies), and asthma (RR, 1.61; 95% CI, 1.07-2.42; eight studies). Exposure to passive smoke significantly increased the risk of lung cancer in adult nonsmokers and increased the risks of asthma, wheeze, lower respiratory infections, and reduced lung function in children. Smoking significantly increased the risk of sleep apnea and asthma exacerbations in adult and pregnant populations, and active and passive smoking increased the risk of tuberculosis.

CONCLUSIONS

These findings have been translated into easily digestible content and published on the SmokeHaz website.

The Risk Factors and Characteristics of COPD Among Nonsmokers in Korea: An Analysis of KNHANES IV and V

PURPOSE

Chronic obstructive pulmonary disease (COPD) is increasing in prevalence and mortality. This study evaluated the prevalence, risk factors, characteristics, and health-related quality of life (HRQoL) of COPD among nonsmokers in Korea.

METHODS

This was a population-based cross-sectional study using data obtained from the Fourth and Fifth Korean National Health and Nutrition Examination Survey, which was conducted from 2007 to 2011.

RESULTS

A total of 15,063 participants completely answered the questionnaire and performed the spirometry. Among them, 59.6 % were nonsmokers and 40.4 % were smokers. The prevalence of nonsmoker COPD was 7.1 %. On multivariate analysis, age ≥65 years (OR, 2.93; 95 % CI, 2.44-3.51), male sex (OR, 2.98; 95 % CI, 2.40-3.71), living in rural area (OR, 1.26; 95 % CI, 1.05-1.51), lower body mass index (BMI) (<18.5 kg/m(2)) (OR, 3.00; 95 % CI, 1.78-5.01), self-reported asthma (OR, 2.72; 95 % CI, 2.05-3.60), and self-reported tuberculosis (OR, 4.73; 95 % CI, 3.63-6.17) showed a significantly higher risk of nonsmoker COPD. Analysis of nonsmoker and smoker COPD revealed that there are more females in nonsmoker COPD patients (73.9 vs. 6.9 %, P < 0.001). Nonsmoker COPD patients presented with impaired mobility, pain/discomfort, and anxiety/depression functions as well as a lower mean EuroQol Five-Dimension Questionnaire utility score, which showed HRQoL.

CONCLUSIONS

The burden of nonsmoker COPD was considerable. Older age, male sex, lower BMI, self-reported asthma, and self-reported tuberculosis were risk factors for nonsmoker COPD and there were differences between nonsmoker and smoker COPD in terms of sex, comorbidities, and HRQoL.

Body mass index and chronic airflow limitation in a worldwide population-based study

Nutritional status has been associated with clinical outcome in chronic airflow limitation (CAL), but epidemiological studies are scarce. We aimed to assess the relationship between body mass index (BMI) and CAL, taking into account confounding factors. 18,606 participants (49% male, 21% smokers, mean age: 55.8 ± 11.2 years, mean BMI: 26.7 ± 5.5 kg/m(2)) of the BOLD initiative from 26 sites in 23 countries were included. CAL was defined as post-bronchodilator forced expiratory volume in the first second/forced vital capacity < lower limit of normal. Low and obese BMI were defined as <21 kg/m(2) and ≥30 kg/m(2), respectively. Multivariate logistic regression analysis controlled for confounders age, sex and smoking, and meta-analysis of between-site heterogeneity and clustering. Prevalence of low and obese BMI, smoking history and prevalence of CAL were highly variable between sites. After adjustment for confounders, the meta-analysis of all sites showed that compared to subjects without CAL, low BMI was more frequent, (adjusted odds ratio (OR): 2.23 (95% confidence interval: 1.75, 2.85)) and conversely, obesity was less frequent in subjects with CAL (adjusted OR: 0.78 (0.65, 0.94)). In a worldwide population sample, CAL was associated with lower BMI, even after adjusting for confounding factors age, gender, smoking and between-site heterogeneity. These results indicate a CAL-specific association with body composition.

Prevalence and underdiagnosis of airway obstruction among middle-aged adults in northern France: The ELISABET study 2011-2013

INTRODUCTION

Airway obstruction (AO), mainly due to chronic obstructive pulmonary disease (COPD) in adults, is a major cause of mortality and poor quality of life. However, few data are available for France. This study was designed to calculate the prevalence AO among middle-aged adults in northern France, explore the associated risk factors and evaluate the underdiagnosis.

METHODS

The Enquête Littoral Souffle Air Biologie Environnement (ELISABET) was a cross-sectional study of a representative sample of 3276 adults aged from 40 to 64 in two urban areas in northern France (Lille and Dunkirk). Participants filled out a questionnaire and performed spirometry testing, without a reversibility test.

RESULTS

The age-standardized estimated prevalence [95% confidence interval] of AO was 16.0% [13.9; 17.9] in Lille and 13.7% [11.7; 15.7] in Dunkirk with the Global initiative for chronic Obstructive Lung Disease (GOLD) definition and 10.8% [9.2; 12.5] and 9.5% [7.9; 11.2] respectively with the lower limit of normal calculated with the Global Lung Initiative (GLI) 2012 equations. AO was associated with age, male gender, tobacco consumption and low body mass index. The underdiagnosis rate was greater than 70%. Previously undiagnosed participants with AO displayed more respiratory symptoms compared with participants without AO and less than participants with previously diagnosed AO.

CONCLUSION

The prevalence of AO in northern France ranged from 9.5 to 16.0%, depending on the centre and definition used. The high underdiagnosis rate observed here suggests that greater efforts should be made to identify individuals presenting with the symptoms and/or risk factors associated with AO.

The effect of dietary antioxidant on the COPD risk: the community-based KoGES (Ansan-Anseong) cohort

Background

Dietary antioxidants have been suggested to have protective role against chronic obstructive pulmonary disease (COPD), but few prospective studies examined this relationship. The prospective study was conducted to evaluate the effect of dietary antioxidants on COPD risk and lung function in the Korean population.

Methods

The data were collected from the community-based Korean Genome Epidemiology Study (KoGES) cohort. To diagnose COPD, forced expiratory volume (FEV₁) and forced vital capacity (FVC) were measured by spirometry. The dietary intake of antioxidant vitamins was estimated from validated Food-Frequency Questionnaire. For the analysis, 325 COPD patients and 6,781 at risk subjects were selected from the cohort of 10,038 subjects. Multiple logistic regression models were used to examine the odds ratio (OR) after adjusting for age, sex, marital status, income, history of asthma, history of tuberculosis, and smoking.

Results

The risk of COPD was positively associated with aging, low education, low household income, lower body mass index, and cigarette smoking. The risk of COPD decreased with increase in the dietary vitamin C (OR_{Q1 vs Q5}=0.66, P_trend=0.03) and vitamin E (OR_{Q1 vs Q5}=0.56, P_trend=0.05) intake, predominantly, in men (P_trend=0.01 and 0.05 for vitamins C and E, respectively). In addition, the lung function was significantly improved with increase in vitamins C (FEV₁, P=0.04; FVC, P=0.03) and E (FEV₁, P=0.03; FVC, P=0.04) intake. No statistically significant interactions were observed between smoking and vitamin C or E intake in relation to COPD risk among men.

Conclusion

Our results suggest the independent beneficial effect of antioxidants, particularly vitamins C and E, on COPD risk and lung function in men.

A case-control study of airways obstruction among construction workers

BACKGROUND

While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers.

METHODS

The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories.

RESULTS

Approximately 18% (95% CI = 2-24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. A measure of all VGDF exposures combined was a strong predictor of COPD risk.

CONCLUSIONS

Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted.

Prevalence and risk factors for COPD in greenhouse farmers: a large, cross-sectional survey of 5,880 farmers from northeast China

Background

COPD is one of the most common chronic diseases, and more and more farmers who were frequently exposed to greenhouse environments were diagnosed with COPD. However, little information is available on the prevalence of COPD among the greenhouse farmers. This study was conducted to assess the prevalence of COPD and investigate the potential risk factors for COPD among the Chinese greenhouse farmers.

Methods

Cross-sectional studies involving a sample of greenhouse farmers living in northeast China were performed via stratified-cluster-random sampling. All subjects were interviewed using a uniform questionnaire and underwent pulmonary function tests between 2006 and 2009, based on the diagnostic criteria of the Global Initiative for Chronic Obstructive Lung Disease. Multiple logistic regression analysis was conducted to examine the risk factors for COPD.

Results

Of the 5,880 greenhouse farmers from northeast China who were originally selected for this study, 5,420 questionnaires were completed. The overall prevalence of COPD in greenhouse farmers was 17.5%. The COPD prevalence was significantly higher in elderly subjects (≥50 years), current smokers, in those with lower body mass index (≤18.5 kg/m²) and less education, in those who were exposed to mushroom, flowers and poultry, and in those living in mountain and coastal region. Multiple logistic regression analysis revealed that age over 50 years old (odds ratio [OR]=298.69, 95% confidence interval [CI]=121.57–733.84), smoking (OR=2.18, 95% CI=1.84–2.59), planting mushroom and flowers (OR=1.46 and 1.53, 95% CI=1.13–1.87 and 1.24–1.95), and living in mountain and coastal region (OR=1.68 and 1.35, 95% CI=1.37–2.06 and 1.10–1.65) were associated with the development of COPD among greenhouse farmers.

Conclusion

In northeast China, COPD is highly prevalent among greenhouse farmers, and advanced age, smoking, planting mushroom, and flowers, as well as living in mountain and coastal regions, are potential risk factors for this disease.

Distribution of body mass index among subjects with COPD in the Middle East and North Africa region: data from the BREATHE study

BACKGROUND

Data describing the potential relationship between chronic obstructive pulmonary disease (COPD) and body mass index (BMI) are limited within the Middle East and North Africa (MENA) region.

OBJECTIVE

To evaluate the distribution of BMI among subjects with COPD in the general population of the MENA region.

METHODS

This study was a subanalysis of the BREATHE study, a cross-sectional survey of COPD conducted in the general population of ten countries in the MENA region and Pakistan. The study population consisted of subjects screened for COPD who documented their weight and height. A COPD questionnaire was administered to subjects who screened positively for COPD in order to collect data on patient characteristics, symptom severity, management and burden of disease, comorbidities, and health care resource utilization and data allowing calculation of the BMI. The COPD Assessment Test (CAT) was administered to those screened positively for COPD to collect data on the impact of respiratory symptoms.

RESULTS

Nine hundred and ninety-six subjects with COPD, who completed the detailed COPD questionnaire and documented their weight and height, were included in this analysis. The mean BMI was 27.7±5.7 kg/m(2). The proportion of COPD patients with a BMI ≥25 kg/m(2) is significantly higher than the proportion with a BMI <25 kg/m(2) (64.6% [n=643] vs 35.4% [n=353], respectively; P<0.0001). There were no significant differences between the distribution of BMI, ages, sex, COPD symptoms, exacerbations, CAT scores, COPD-associated health care resource consumption, and GOLD severity groups. However, the occurrence of comorbidities such as diabetes and cardiovascular diseases seemed to be significantly associated with obese or morbidly obese status (P=0.02).

CONCLUSION

In the MENA region, the majority of COPD subjects were overweight or obese, and comorbidities such as diabetes or cardiovascular diseases are likely to be associated with COPD when BMI is in the obese or morbidly obese ranges.

Body mass index, respiratory conditions, asthma, and chronic obstructive pulmonary disease

BACKGROUND

This study aims to assess the relationship of body mass index (BMI) status with respiratory conditions, asthma, and chronic obstructive pulmonary disease (COPD) in a state population.

METHODS

Self-reported data from 11,868 adults aged ≥18 years in the 2012 South Carolina Behavioral Risk Factor Surveillance System telephone survey were analyzed using multivariable logistic regression that accounted for the complex sampling design and adjusted for sex, age, race/ethnicity, education, smoking status, physical inactivity, and cancer history.

RESULTS

The distribution of BMI (kg/m(2)) was 1.5% for underweight (<18.5), 32.3% for normal weight (18.5-24.9), 34.6% for overweight (25.0-29.9), 26.5% for obese (30.0-39.9), and 5.1% for morbidly obese (≥40.0). Among respondents, 10.0% had frequent productive cough, 4.3% had frequent shortness of breath (SOB), 7.3% strongly agreed that SOB affected physical activity, 8.4% had current asthma, and 7.4% had COPD. Adults at extremes of body weight were more likely to report having asthma or COPD, and to report respiratory conditions. Age-adjusted U-shaped relationships of BMI categories with current asthma and strongly agreeing that SOB affected physical activity, but not U-shaped relationship with COPD, persisted after controlling for the covariates (p < 0.001). Morbidly obese but not underweight or obese respondents were significantly more likely to have frequent productive cough and frequent SOB than normal weight adults after adjustment.

CONCLUSION

Our data confirm that both underweight and obesity are associated with current asthma and obesity with COPD. Increased emphasis on exercise and nutrition may improve respiratory conditions.

Risk factors for chronic obstructive pulmonary disease among never-smokers in Korea

Background

Chronic obstructive pulmonary disease (COPD) patients include those who have never smoked. However, risk factors other than smoking in never-smokers have not been elucidated sufficiently. This study investigated the risk factors for COPD among never-smokers in Korea using population-based data.

Methods

The data were retrieved from the Korean National Health and Nutrition Survey IV conducted from 2007 to 2009. Among subjects aged 40 years or older who underwent appropriate pulmonary function tests, never-smokers not diagnosed with asthma and not showing a restrictive pattern on pulmonary function tests were enrolled. Risk factors of COPD in never-smokers were analyzed using logistic regression models.

Results

Among 24,871 participants in the representative Korean cohort, 3,473 never-smokers were enrolled. COPD patients accounted for 7.6% of the never-smokers. In the logistic regression analysis, low education status (odds ratio [OR]: 2.0; 95% confidence interval [CI]: 1.2–3.2), occupational exposure (OR: 2.6; 95% CI: 1.3–5.3), a history of tuberculosis (OR: 4.5; 95% CI: 2.3–8.7), bronchiectasis (OR: 6.0; 95% CI: 1.4–25.4), male sex (OR: 4.2; 95% CI: 2.6–6.7), advanced age (60–69 years vs 40–49 years; OR: 3.8; 95% CI: 2.0–7.0), and being underweight (body mass index <18.5 vs 18.0–24.9 kg/m²; OR: 3.1; 95% CI: 1.0–9.4) were associated with the development of COPD.

Conclusion

Low education status, manual labor, a history of tuberculosis and bronchiectasis, as well as male sex, advanced age and being underweight were risk factors for COPD in Korean never-smokers.

Obesity and extent of emphysema depicted at CT

AIM

To investigate the underlying relationship between obesity and the extent of emphysema depicted at CT.

METHODS AND MATERIALS

A dataset of 477 CT examinations was retrospectively collected from a study of chronic obstructive pulmonary disease (COPD). The low attenuation areas (LAAs; ≤950 HU) of the lungs were identified. The extent of emphysema (denoted as %LAA) was defined as the percentage of LAA divided by the lung volume. The association between log-transformed %LAA and body mass index (BMI) adjusted for age, sex, the forced expiratory volume in one second as percent predicted value (FEV1% predicted), and smoking history (pack years) was assessed using multiple linear regression analysis.

RESULTS

After adjusting for age, gender, smoking history, and FEV1% predicted, BMI was negatively associated with severe emphysema in patients with COPD. Specifically, one unit increase in BMI is associated with a 0.93-fold change (95% CI: 0.91-0.96, p<0.001) in %LAA; the estimated %LAA for males was 1.75 (95% CI: 1.36-2.26, p<0.001) times that of females; per 10% increase in FEV1% predicated is associated with a 0.72-fold change (95% CI: 0.69-0.76, p<0.001) in %LAA.

CONCLUSION

Increasing obesity is negatively associated with severity of emphysema independent of gender, age, and smoking history.

Overweight and obesity may lead to under-diagnosis of airflow limitation: findings from the Copenhagen City Heart Study

BACKGROUND

The prevalence of obesity has increased during the last decades and varies from 10-20% in most European countries to approximately 32% in the United States. However, data on how obesity affects the presence of airflow limitation (AFL) defined as a reduced ratio between forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) are scarce.

METHODS

Data was derived from the third examination of the Copenhagen City Heart Study from 1991 until 1994 (n = 10,135). We examine the impact of different adiposity markers (weight, body mass index (BMI), waist circumference, waist-hip ratio, and abdominal height) on AFL. AFL was defined in four ways: FEV1/FVC ratio < 0.70, FEV1/FVC ratio < lower limit of normal (LLN), FEV1/FVC ratio <0.70 including at least one respiratory symptom, and FEV1/FVC ratio < LLN and FEV1% of predicted < LLN.

RESULTS

All adiposity markers were positively and significantly associated with FEV1/FVC independent of age, sex, height, smoking status, and cumulative tobacco consumption. Among all adiposity markers, BMI was the strongest predictor of FEV1/FVC. FEV1/FVC increased with 0.04 in men and 0.03 in women, as BMI increased with 10 units (kg · m-2). Consequently, diagnosis of AFL was significantly less likely in subjects with BMI ≥ 25 kg · m-2 with odds ratios 0.63 or less compared to subjects with BMI between 18.5-24.9 kg · m-2 when AFL was defined as FEV1/FVC < 0.70.

CONCLUSION

High BMI reduces the probability of AFL. Ultimately, this may result in under-diagnosis and under-treatment of COPD among individuals with overweight and obesity.

Body size and physical activity in relation to incidence of chronic obstructive pulmonary disease

BACKGROUND

Limited evidence suggests that adiposity and lack of physical activity may increase the risk of chronic obstructive pulmonary disease (COPD). We investigated the relation of body size and physical activity with incidence of COPD.

METHODS

We obtained data on anthropometric measurements and physical activity from 113,279 participants in the National Institutes of Health-AARP Diet and Health Study who reported no diagnosis of COPD at baseline (1995-1996). We estimated associations between these measurements and subsequent diagnosis of COPD between 1996 and 2006, with extensive adjustment for smoking and other potentially confounding variables.

RESULTS

Participants reported 3648 new COPD diagnoses during follow-up. The incidence of COPD was higher in both severely obese (body mass index [BMI] ≥ 35) and underweight (BMI < 18.5) participants, but after adjustment for waist circumference, only underweight remained positively associated with COPD (relative risk [RR] 1.56, 95% confidence interval [CI] 1.15-2.11). Larger waist circumference (highest v. normal categories, adjusted RR 1.72, 95% CI 1.37-2.16) and higher waist-hip ratio (highest v. normal categories, adjusted RR 1.46, 95% CI 1.23-1.73) were also positively associated with COPD. In contrast, hip circumference (highest v. normal categories, adjusted RR 0.78, 95% CI 0.62-0.98) and physical activity (≥ 5 v. 0 times/wk, adjusted RR 0.71, 95% CI 0.63-0.79) were inversely associated with COPD.

INTERPRETATION

Obesity, in particular abdominal adiposity, was associated with an increased risk of COPD, and increased hip circumference and physical activity were associated with a decreased risk of COPD. These findings suggest that following guidelines for a healthy body weight, body shape and physical activity decrease the risk of COPD.

Spirometry and health status worsen with weight gain in obese smokers but improve in normal-weight smokers

RATIONALE

The literature on the effect of obesity and weight gain on respiratory outcomes in smokers is contradictory.

OBJECTIVE

To examine the cross-sectional effect of body mass index (BMI) and the longitudinal effect of change in BMI upon spirometry and health status among smokers at risk for and with milder chronic obstructive pulmonary disease (COPD).

METHODS

Participants from the Lovelace Smokers' Cohort were followed for a median period of 6 years, 75% of whom were at risk and 25% of whom had COPD at baseline examination. BMI and gain in BMI were examined as continuous independent variables overall and after stratification into three categories (normal-weight, overweight, and obese) determined on the basis of baseline weight. Spirometry and health status (as assessed by St. George Respiratory Questionnaire total and subscale scores) were dependent variables. Covariates included age, sex, ethnicity, pack-years of smoking, and current smoking status. Cross-sectional analysis used linear and logistic regression; longitudinal analysis used a mixed model approach.

MEASUREMENTS AND MAIN RESULTS

In cross-sectional analyses, higher BMI was associated with worse health status among obese smokers but with better health status among normal-weight smokers. In longitudinal analyses, weight gain was associated with a decrease in FEV1 and health status among obese smokers and with an increase in these outcomes among normal-weight smokers.

CONCLUSIONS

Weight gain affects respiratory outcomes differently between obese and normal-weight smokers. Whereas FEV1 and health status decrease with weight gain among obese smokers, they improve among normal-weight smokers. The nonlinear relationship between weight gain and respiratory outcomes suggests that this effect of excess weight is unlikely to be mechanical alone.

The Saudi Guidelines for the Diagnosis and Management of COPD

The Saudi Thoracic Society (STS) launched the Saudi Initiative for Chronic Airway Diseases (SICAD) to develop a guideline for the diagnosis and management of chronic obstructive pulmonary disease (COPD). This guideline is primarily aimed for internists and general practitioners. Though there is scanty epidemiological data related to COPD, the SICAD panel believes that COPD prevalence is increasing in Saudi Arabia due to increasing prevalence of tobacco smoking among men and women. To overcome the issue of underutilization of spirometry for diagnosing COPD, handheld spirometry is recommended to screen individuals at risk for COPD. A unique feature about this guideline is the simplified practical approach to classify COPD into three classes based on the symptoms as per COPD Assessment Test (CAT) and the risk of exacerbations and hospitalization. Those patients with low risk of exacerbation (<2 in the past year) can be classified as either Class I when they have less symptoms (CAT < 10) or Class II when they have more symptoms (CAT ≥ 10). High-risk COPD patients, as manifested with ≥2 exacerbation or hospitalization in the past year irrespective of the baseline symptoms, are classified as Class III. Class I and II patients require bronchodilators for symptom relief, while Class III patients are recommended to use medications that reduce the risks of exacerbations. The guideline recommends screening for co-morbidities and suggests a comprehensive management approach including pulmonary rehabilitation for those with a CAT score ≥10. The article also discusses the diagnosis and management of acute exacerbations in COPD.

Correlation of BMI and oxygen saturation in stable COPD in Northern India

Background:

Chronic obstructive pulmonary disease (COPD) is associated with clinically relevant extra pulmonary manifestations; one of them is weight loss. However, there are very few studies from North India available in relation to body mass index (BMI) and Oxygen saturation (SpO₂) with COPD.

Aims:

To study the prevalence of undernutrition among stable COPD patients and correlation of COPD severity with SpO₂ and BMI.

Settings and Design:

A prospective study was carried out at a tertiary care hospital.

Subjects and Methods:

COPD patients were diagnosed and staged as per global initiative for chronic obstructive lung disease (GOLD) guidelines. SpO₂ was measured using pulse oxymeter and BMI categorization was done as per new classification for Asian Indians (2009). Statistical analysis was done using Statistical Package for Social Sciences Version 15.0.

Results:

Out of 147 COPD patients, 85 (57.8%) were undernourished. The prevalence of undernourished BMI was 25%, 50.8%, 61.7%, and 80% in stage I, II, III and IV respectively; statistically significant (P < 0.050). The mean SpO₂ was 95.50 ± 1.41, 95.05 ± 2.42, 94.37 ± 2.28 and 93.05 ± 1.39 in stage I, II, III and IV respectively; statistically significant (F = 4.723; P = 0.004).

Conclusions:

The overall prevalence of under nutrition among COPD patients was 57.8%. With increasing COPD stage the BMI and median SpO₂ value decreased in progressive manner. Association of SpO₂ and COPD stages could be explored further in order to suggest an additional marker of disease severity that would add a new dimension in the management of COPD.