Body mass index and chronic obstructive pulmonary disease-related mortality: a nationally representative prospective study of 220,000 men in China

Nebulized platelet-derived extracellular vesicles attenuate chronic cigarette smoke-induced murine emphysema

Chronic obstructive pulmonary disease (COPD) is a prevalent lung disease usually resulting from cigarette smoking (CS). Cigarette smoking induces oxidative stress, which causes inflammation and alveolar epithelial cell apoptosis and represents a compelling therapeutic target for COPD. Purified human platelet-derived exosome product (PEP) is endowed with antioxidant enzymes and immunomodulatory molecules that mediate tissue repair. In this study, a murine model of CS-induced emphysema was used to determine whether nebulized PEP can influence the development of CS-induced emphysema through the mitigation of oxidative stress and inflammation in the lung. Nebulization of PEP effectively delivered the PEP vesicles into the alveolar region, with evidence of their uptake by type I and type II alveolar epithelial cells and macrophages. Lung function testing and morphometric assessment showed a significant attenuation of CS-induced emphysema in mice treated with nebulized PEP thrice weekly for 4 weeks. Whole lung immuno-oncology RNA sequencing analysis revealed that PEP suppressed several CS-induced cell injuries and inflammatory pathways. Validation of inflammatory cytokines and apoptotic protein expression on the lung tissue revealed that mice treated with PEP had significantly lower levels of S100A8/A9 expressing macrophages, higher levels of CD4+/FOXP3+ Treg cells, and reduced NF-κB activation, inflammatory cytokine production, and apoptotic proteins expression. Further validation using in vitro cell culture showed that pretreatment of alveolar epithelial cells with PEP significantly attenuated CS extract-induced apoptotic cell death. These data show that nebulization of exosomes like PEP can effectively deliver exosome cargo into the lung, mitigate CS-induced emphysema in mice, and suppress oxidative lung injury, inflammation, and apoptotic alveolar epithelial cell death.

The clinical characteristics and treatment response of patients with chronic obstructive pulmonary disease with low body mass index

Background: This study aimed to analyze the clinical characteristics and treatment response of patients with chronic obstructive pulmonary disease (COPD) with low body mass index (BMI). Methods: In this cross-sectional study, we enrolled patients with stable COPD from the database setup by the Second Xiangya Hospital of Central South University. We classified the patients into three groups based on BMI: low-BMI (<18.5 kg/m²), normal-BMI (≥18.5 and <24.0 kg/m²), and high-BMI (≥24 kg/m²) groups. We defined clinically important deterioration (CID) as a COPD Assessment Test (CAT) score increase of ≥2 and minimum clinically important difference (MCID) as a CAT score decrease of ≥2 during 6 months of follow-up. We recorded the number of exacerbations and mortality during 1 year of follow-up. Results: A total of 910 COPD patients were included with 144 (15.8%) patients in low-BMI, 475 (52.2%) in normal-BMI, and 291 (32.0%) in high-BMI groups. Patients with low BMI had worse pulmonary function, higher symptom scores, and exacerbations in the past year compared with normal- and high-BMI groups (p < 0.05). Logistic regression analysis revealed that age, Global Initiative for Chronic Obstructive Lung Disease grades 3 and 4, and hospitalizations in the past year were independent risk factors for patients with low BMI (p < 0.05). After 1 year of follow-up, patients with low BMI had higher mortality and number of hospitalizations. Patients with low BMI were more likely to attain CID and less likely to attain MCID compared with patients with high BMI (p < 0.05). In addition, patients with low BMI treated with long-acting β2-agonist (LABA)+long-acting muscarinic antagonist (LAMA) and LABA+LAMA+inhaled corticosteroid (ICS) were more likely to attain MCID than those treated with LABA+ICS and LAMA (p < 0.05). Conclusion: COPD patients with low BMI had worse pulmonary function, higher symptom scores, and higher risk of future hospitalizations and mortality and were less likely to attain MCID and more likely to attain CID. It is worth noting that patients with low BMI treated with LABA+LAMA and LABA+LAMA+ICS were more likely to attain MCID than those treated with LABA+ICS and LAMA.

Correlation of Body Mass Index and Oxygen Saturation in Chronic Obstructive Pulmonary Disease Patients at a Tertiary Care Center in Nepal: A Cross-Sectional Study

Purpose

Chronic obstructive pulmonary disease (COPD) is a major cause of mortality and morbidity worldwide. COPD is associated with clinically relevant pulmonary and extrapulmonary manifestations, including hypoxemia and weight loss. The correlation of body mass index (BMI) and oxygen saturation (SpO2) with COPD grades may provide a useful additional marker for understanding and managing the disease. The aim of the study was to study the correlation of BMI and oxygen saturation with COPD in patients presenting to a tertiary care center in Nepal.

Patients and Methods

A descriptive cross-sectional study was conducted among 145 COPD patients visiting the Department of Medicine in Shree Birendra Hospital between 1 March 2019 and 28 February 2020. A non-probability purposive sampling method was used and data were analyzed using SPSS version 21. A p-value of <0.05 was considered significant.

Results

Out of 145 COPD patients, 58 (40%) were underweight, 53 (36.55%) were of normal weight, 20 (13.79%) were overweight, and 14 (9.6%) were obese. The number of underweight patients was highest in COPD grade 4 and lowest in COPD grade 1. The proportion of subjects with underweight BMI and hypoxia increased with COPD severity, and both were statistically significant (p-values <0.01).

Conclusion

Our study shows that BMI and oxygen saturation have an inverse association with COPD severity. The correlation of BMI and oxygen saturation with COPD grade could provide a supplementary marker of disease severity, which could be useful in the understanding of the disease process and subsequent management of COPD.

Validation of Asian Body Mass Index Cutoff Values for the Classification of Malnutrition Severity According to the Global Leadership Initiative on Malnutrition Criteria in Patients with Chronic Obstructive Pulmonary Disease Exacerbations

Low body mass index (BMI) is an independent predictor of prolonged hospital stay and mortality in patients with chronic obstructive pulmonary disease (COPD). However, to the best of our knowledge, no studies have examined the validity of Asian BMI cutoff values for classifying severity based on the Global Leadership Initiative on Malnutrition (GLIM) criteria in patients with acute COPD exacerbations. This study sought to validate whether Asian BMI cutoff values can accurately predict 30-day in-hospital mortality, length of stay, and 90-day readmission outcomes for patients with acute COPD exacerbations. The present retrospective cohort study was conducted using a large claims database created by the JMDC. Patients were classified into three groups according to the severity of low BMI assessed using Asian BMI cutoff values. As a result, 624 (29.4%) had severely low BMI, and 444 (20.9%) had moderately low BMI. The severity of low BMI, as assessed by the Asian BMI cutoff values used in the GLIM criteria, was independently associated with 30-day in-hospital mortality (moderately low BMI: HR, 1.87; 95% CI, 1.13−3.08; p = 0.014 and severely low BMI: HR, 2.55; 95% CI, 1.66−3.92; p < 0.001). The Asian BMI cutoff values used to classify the severity of malnutrition in the GLIM criteria are clinically functional for predicting the prognosis of patients with acute COPD exacerbations.

Inverse association between body mass index and all-cause mortality in rural chinese adults: 15-year follow-up of the Anqing cohort study

OBJECTIVE

To investigate the association between body mass index (BMI) and all-cause mortality in a Chinese rural population.

DESIGN

Prospective cohort study.

SETTING

This study was conducted from 2003 to 2018 in Anqing, Anhui Province, China.

PARTICIPANTS

17 851 participants aged 25-64 years (49.4% female) attending physical examinations and questionnaire were included in this study. The inclusion criterion was families having a minimum of three participating siblings. The exclusion criteria included participants without family number and BMI data at baseline.

OUTCOME MEASURES

The outcome measure was all-cause mortality. Generalized estimating equation (GEE) regression analysis was performed to determine the association between baseline BMI and all-cause mortality.

RESULTS

During a mean follow-up period of 14.1 years, 730 deaths (8.0%) occurred among men, and 321 deaths (3.6%) occurred among women. The mean BMI for males was 21.3[Formula: see text] kg/m², and for female it was 22.1±3.1 kg/m². Baseline BMI was significantly inversely associated with all-cause mortality risk for per SD increase (OR, 0.79 (95% CI, 0.72 to 0.87) for males; OR, 0.88 (95% CI, 0.76 to 1.01) for females). When BMI was stratified with cut points at 20 and 24 kg/m², compared with the low BMI group, a significantly lower risk of death was found in the high BMI group (BMI ≥24: OR, 0.57 (95% CI, 0.43 to 0.77) in males; 0.65 (95% CI, 0.46 to 0.93) in females) after adjustment for relevant factors.

CONCLUSIONS

In this relatively lean rural Chinese population, the risk of all-cause mortality decreased with increasing BMI. The excess risk of all-cause mortality associated with a high BMI was not seen among this rural population.

Challenging the obesity paradox: extreme obesity and COPD mortality in the SUMMIT trial

Populations with COPD demonstrate higher survival in overweight and obese compared with normal weight; the “obesity paradox”. Relationships in less-severe COPD are unclear, as is the impact of cardiovascular risk, and few studies include individuals at extremes of obesity.

 We examined the relationship between body mass index (BMI; defined as underweight: <20 kg·m⁻², normal: 20–25 kg·m⁻², overweight: 25– <30 kg·m⁻², obese class I: 30– <35 kg·m⁻², class II: 35– <40 kg·m⁻² and class III: ≥40 kg·m⁻²), morbidity, and mortality in the SUMMIT trial population (n=16 485), characterised by moderate COPD and heightened cardiovascular risk with a substantial proportion with class III obesity. The association between BMI category and time to event was modelled via proportional hazards (reference normal weight) adjusted for demographics and cardiorespiratory disease.

 Consistent with the paradox, underweight individuals demonstrated higher mortality (hazard ratio (HR) 1.31 (95% CI 1.04–1.64)), with lower mortality among overweight (HR 0.62 (95% CI 0.52–0.73)) and obese class I (HR 0.75 (95% CI 0.62–0.90)). However, mortality increased in obese class III (HR 1.36 (95% CI 1.00–1.86)). Death was primarily attributable to cardiovascular causes.

 Within a large, multinational cohort with moderate COPD and increased cardiovascular risk, the phenomenon of reduced mortality with obesity did not persist at BMI >40 kg·m⁻², suggesting that obesity may not remain protective at the extremes in this population.

In a population with moderate COPD, at heightened cardiovascular risk and containing a substantial proportion of individuals with BMI ≥40 kg/m², BMI and mortality demonstrate a U-shaped (rather than J-shaped) relationshiphttps://bit.ly/3hDztI6

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.

Underweight rather than adiposity is an important predictor of death in rural Chinese adults: a cohort study

BACKGROUND

To assess the associations of body mass index (BMI) with all-cause and cause-specific mortalities among rural Chinese.

METHODS

A prospective study of 28 895 individuals was conducted from 2006 to 2014 in rural Deqing, China. Height and weight were measured. The association of BMI with mortality was assessed by using Cox proportional hazards model and restricted cubic spline regression.

RESULTS

There were a total of 2062 deaths during an average follow-up of 7 years. As compared with those with BMI of 22.0-24.9 kg/m², an increased risk of all-cause mortality was found for both underweight men (BMI <18.5 kg/m²) (adjusted HR (aHR): 1.45, 95% CI: 1.18 to 1.79) and low normal weight men (BMI of 18.5-21.9 kg/m²) (aHR: 1.20, 95% CI: 1.03 to 1.38). A J-shaped association was observed between BMI and all-cause mortality in men. Underweight also had an increased risk of cardiovascular disease and cancer mortalities in men. The association of underweight with all-cause mortality was more pronounced in ever smokers and older men (60+ years). The results remained after excluding participants who were followed up less than 1 year.

CONCLUSION

The present study suggests that underweight is an important predictor of mortality, especially for elderly men in the rural community of China.

Shape of BMI-Mortality Risk Associations: Reverse Causality and Heterogeneity in a Representative Cohort of US Adults

OBJECTIVE

This study examines BMI-mortality associations and evaluates strategies intended to limit reverse causality. Heterogeneity in BMI-mortality risk associations across subgroups and causes of death is explored.

METHODS

A cohort of 654,382 adults from the US National Health Interview Survey was constructed. Associations between unit BMI levels and mortality were estimated using Cox proportional hazards models, including and excluding the first 5 years of follow-up, with and without controls for smoking or preexisting conditions, and including and excluding ever-smokers and individuals with preexisting conditions. Stratified analyses by individual characteristics were performed.

RESULTS

Addressing reverse causality led to reduced risk of mortality among those with low BMI levels (<18 kg/m² ). Excluding ever-smokers and individuals with preexisting conditions further led to increased risk among those with high BMI levels (between 33 kg/m² and >40 kg/m² ) and lowered the estimated nadir risk from 27 kg/m² to 23 kg/m² . After excluding ever-smokers and individuals with preexisting conditions, limiting the analysis to >5 years of follow-up produced no substantive changes. Heterogeneous results were observed across individual characteristics, particularly age and causes of death.

CONCLUSIONS

The exclusion of smokers and individuals with preexisting conditions alters the BMI-mortality risk association and results in a somewhat lower range of BMI with minimum mortality risk.

Low BMI and weight loss aggravate COPD mortality in men, findings from a large prospective cohort: the JACC study

To clarify how low BMI and weight loss were associated with risk of chronic obstructive pulmonary disease (COPD) mortality, in a large prospective cohort of the general population across Japan, the Japan Collaborative Cohort Study, conducted between 1988 and 2009. A total of 45,837 male residents were observed for a median period of 19.1 years. Self-administered questionnaires, collecting information on BMI, weight loss since the age of 20, lifestyles, history of diseases, as well as records of COPD mortality, were analysed at 2019. During follow-up, 268 participants died from COPD. The multivariate-adjusted hazard ratio (95% confidence interval) of COPD mortality associated with a 1-SD increment of body mass index (BMI) was 0.48 (0.41–0.57), while for weight change from age of 20 (+ 2.0 kg) it was 0.63 (0.59–0.68). These associations were persistently observed after stratifications with smoking status, excluding those having airway symptoms in the baseline survey, and excluding early COPD deaths within 5, 10 and 15 years. Our study suggests that BMI and weight change since the age of 20 could be markers for COPD prognosis, indicated by risk of COPD mortality.

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.

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.

Predictors of mortality in patients with COPD after 9 years

Background

COPD is one of the leading causes of morbidity and mortality in the world; however, the most varied amounts of clinical and laboratory characteristics acts in different ways in the mortality among over time. Therefore, this study aimed to evaluate the predictors of mortality in patients with COPD after 9 years.

Patients and methods

One hundred and thirty-three patients with COPD were assessed at baseline by spirometry, pulse oximetry (SpO₂), body composition, intensity of dyspnea, distance walked in the 6-minute walk test (6MWT), and Charlson Comorbidity Index (CCI).

Results

After 9 years, it was not possible to identify the lifetime of 4 patients who died and of 19 patients who stopped follow-up; thus, 110 patients were included in the analysis of predictors of mortality (67% male, 65±9 years old, and FEV₁: 52.5 [40%–73%]). Male sex, age, SpO₂, Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index, and frequency of exacerbations in the first 3 years of follow-up were considered in the model. Patients classified at baseline with BODE class 2 (HR: 2.62, 95% CI: 1.36–5.04; P=0.004), BODE class 3 (HR: 2.54, 95% CI: 1.15–5.61; P=0.02), and BODE class 4 (HR: 15.35, 95% CI: 3.11–75.75; P=0.001) showed increased risk of death compared to those with BODE class 1. The CCI (HR: 1.29, 95% CI: 1.00–1.68; P=0.04) and the number of exacerbations in the first 3 years (HR: 1.32, 95% CI: 1.00–1.76; P=0.04) also showed increased risk of death. By replacing the BODE index for the variables that compose it, those with body mass index ≤21 kg/m² showed increased risk of death compared to those with body mass index (BMI)>21 kg/m² (HR: 2.70, 95% CI: 1.38–5.25; P=0.003).

Conclusion

After 9 years, we identified that those with high BODE index, greater CCI, greater frequency of exacerbations in the first 3 years, and BMI ≤21 kg/m² showed increased risk of death.

Body mass index of patients with chronic obstructive pulmonary disease is associated with pulmonary function and exacerbations: a retrospective real world research

Background

Chronic obstructive pulmonary disease (COPD) is prevalent in China. The role of body mass index (BMI) in COPD progression and prognosis is unclear. We analyzed the association between BMI and pulmonary function, inflammation levels and exacerbation in Chinese COPD patients.

Methods

Our retrospective real world research included 744 patients with COPD diagnosed by spirometry and hospitalized from January 1st, 2014 to December 31st, 2016. The indicators were gathered from hospital records database and frequency of exacerbation in the three years were followed up. All 744 patients were divided into four groups by BMI grades. We analyzed the association between BMI and pulmonary function, inflammation levels and exacerbation by Spearman bivariate correlations, Kruskal-Wallis test, Mann-Whitney U test and logistic regression.

Results

The singly proportion (median of BMI) of these patients in underweight, normal weight, overweight and obesity was 7.80% (17.54), 45.97% (22.12), 27.96% (27.00) and 18.28% (31.25) respectively. With increasing of BMI grades, the values of forced expiratory volume in 1 second (FEV₁), peak expiratory flow (PEF), forced expiratory flow (FEF25/50/75) and diffusing capacity of carbon monoxide (DLCO) were correspondingly increasing; the percentage of neutrophils and C-reactive protein (CRP) presented significant declining trend while the trend of the percentage of eosinophils was negative; the dose of systemic corticosteroid and length of stay present decreasing tendency; the frequency of exacerbation and hospitalization were decreasing. These were similar results in gender, smoking status COPD subgroups.

Conclusions

In our study, BMI was moderately correlated with pulmonary function positively and exacerbations negatively. To some extent, BMI might be a useful indicator to predict the prognosis of COPD patients and for long-term management.

BMI-mortality association: shape independent of smoking status but different for chronic lung disease and lung cancer

Background

Besides smoking, low or high body mass index (BMI) is associated with chronic lung disease (CLD). It is unclear how CLD is associated with BMI, whether smoking interacts with this association, and how the associations differ from the patterns known for lung cancer.

Population and Methods

Our population comprised 35,212 individuals aged 14–99, who participated in population-based surveys conducted in 1977–1993 in Switzerland (mortality follow-up until 2014). We categorized smokers into never, former, light, and heavy; and BMI into underweight, normal weight, overweight, and obese. Hazard ratios (HRs) were obtained with multivariable Cox proportional hazards models.

Results

CLD mortality was strongly associated with being underweight. This was mainly due to the effect in men (HR 5.04 [2.63–9.66]) and also prevailed in never smokers (HR 1.81 [1.11–3.00]). Obesity was also associated with CLD mortality (HR men: 1.37 [1.01–1.86], women: 1.39 [0.90–2.17]), but not with lung cancer mortality. In line with lung cancer, for CLD, the BMI–mortality association followed the same shape in all smoking categories, suggesting that this association was largely independent of smoking status.

Conclusion

The shape of the BMI–mortality association was inversely linear for lung cancer but followed a U-shape for CLD. Further research should examine the potentially protective effect of obesity on lung cancer occurrence and the possibly hazardous impact of underweight on CLD development.

Large-Scale Epidemiologic Studies of Cardiovascular Diseases in China: Need for Improved Data Collection, Methods, Transparency, and Documentation

With the advent of international precision medicine initiatives, it is important to evaluate existing large-scale studies to inform future investigation. This study sought to review, describe, and evaluate all large-scale cardiovascular disease (CVD) studies completed in China. We undertook a review of all large-scale CVD studies completed in China to describe and evaluate their design, implementation, and dissemination in published medical reports. Seventeen studies met the inclusion criteria. There were substantial variations in study design, geographic location, and data collection. Most studies lacked standard study names, did not publish their methods, and provided no publicly available data. Few studies included underdeveloped regions or minority groups. Most published articles contained only descriptions of the average population at risk of CVD, and no study predicted individual CVD risk or identified people at high risk. Future CVD studies in China may need to incorporate stronger systematic data collection methods, increased data transparency, clearer documentation, and standard study names to most gain from China's burgeoning field of CVD research.

Long-term Fine Particulate Matter Exposure and Nonaccidental and Cause-specific Mortality in a Large National Cohort of Chinese Men

BACKGROUND

Cohort studies in North America and western Europe have reported increased risk of mortality associated with long-term exposure to fine particles (PM_2.5), but to date, no such studies have been reported in China, where higher levels of exposure are experienced.

OBJECTIVES

We estimated the association between long-term exposure to PM_2.5 with nonaccidental and cause-specific mortality in a cohort of Chinese men.

METHODS

We conducted a prospective cohort study of 189,793 men 40 y old or older during 1990-91 from 45 areas in China. Annual average PM_2.5 levels for the years 1990, 1995, 2000, and 2005 were estimated for each cohort location using a combination of satellite-based estimates, chemical transport model simulations, and ground-level measurements developed for the Global Burden of Disease (GBD) 2013 study. A Cox proportional hazards regression model was used to estimate hazard ratios (HR) for nonaccidental cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD), and lung-cancer mortality. We also assessed the shape of the concentration-response relationship and compared the risk estimates with those predicted by Integrated Exposure-Response (IER) function, which incorporated estimates of mortality risk from previous cohort studies in western Europe and North America.

RESULTS

The mean level of PM_2.5 exposure during 2000-2005 was 43.7 μg/m³ (ranging from 4.2 to 83.8 μg/m³). Mortality HRs (95% CI) per 10-μg/m³ increase in PM_2.5 were 1.09 (1.08, 1.09) for nonaccidental causes; 1.09 (1.08, 1.10) for CVD, 1.12 (1.10, 1.13) for COPD; and 1.12 (1.07, 1.14) for lung cancer. The HR estimate from our cohort was consistently higher than IER predictions.

CONCLUSIONS

Long-term exposure to PM_2.5 was associated with nonaccidental, CVD, lung cancer, and COPD mortality in China. The IER estimator may underestimate the excess relative risk of cause-specific mortality due to long-term exposure to PM_2.5 over the exposure range experienced in China and other low- and middle-income countries. https://doi.org/10.1289/EHP1673.

Body Mass Index and Mortality: A 10-Year Prospective Study in China

Although several studies have evaluated the role of body weight as a risk factor for mortality, most studies have been conducted in Western populations and the findings remain controversial. We performed a prospective study to examine the association between body mass index (BMI) and all-cause mortality in Yinzhou District, Ningbo, China. At baseline, 384,533 subjects were recruited through the Yinzhou Health Information System between 2004 and 2009. The final analysis was restricted to 372,793 participants (178,333 men and 194,460 women) aged 18 years and older. Cox proportional hazards models were used to estimate hazard ratios(HRs) and 95% confidence intervals(CIs). We found an increased risk of all-cause mortality among individuals with BMI levels <22.5-24.9, although several groups were not statistically significant-adjusted HRs for persons with BMIs of <15.0, 15.0-17.4, 17.5-19.9, and 20.0-22.4 were 1.61(95% CI: 1.17-2.23), 1.07(0.94-1.20), 1.04(0.98-1.10), 1.06(1.02-1.11), respectively. In the upper BMI range, subjects with BMIs of 25.0-34.9 had a reduced risk of all-cause mortality. Sensitivity analyses excluding smokers, those with prevalent chronic disease or those with less than four years of follow-up did not materially alter these results. Our findings provide evidence for an inverse association of BMI and mortality in this population.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.

Spatiotemporal Variations in Chronic Obstructive Pulmonary Disease Mortality in China: Multilevel Evidence from 2006 to 2012

Mortality of Chronic Obstructive Pulmonary Disease (COPD) is on the decline in China. It is not known if this trend occurs across all areas or whether spatiotemporal variations manifest. We used data from the nationally representative China Mortality Surveillance System to calculate annual COPD mortality counts (2006-2012) stratified by 5-year age groups (aged > 20), gender and time for 161 counties and districts (Disease Surveillance Points, or DSP). These counts were linked to annually adjusted denominator populations. Multilevel negative binomial regression with random intercepts and slopes were used to investigate spatiotemporal variation in COPD mortality adjusting for age, gender and area-level risk factors. COPD mortality rate decreased markedly from 105.1 to 73.7 per 100,000 during 2006 to 2012 and varied over two-fold between DSPs across China. Mortality rates were higher in the west compared with the east (Rate ratio (RR) 2.15, 95% confidence intervals (CI) 1.73, 2.68) and in rural compared with the urban (RR 1.87, 95% CI 1.55, 2.25). Adjustment for age, gender, urban/rural, region, smoking prevalence, indoor air pollution, mean body mass index and socioeconomic circumstances accounted for 67% of the geographical variation. Urban/rural differences in COPD mortality narrowed over time, but the magnitude of the east-west inequality persisted without change. Immediate action via large-scale interventions to enhance the prevention and management of COPD are needed specifically within China's western region in order to tackle this crucial health inequality and leading preventable cause of death.

Risk factor for respiratory death after lung cancer surgery in octogenarians

Background

As society ages, the frequency of elderly patients undergoing surgery for lung cancer is increasing. However, the indications for surgery in octogenarians are still controversial. We examined the outcomes of elderly patients undergoing thoracic surgery for lung cancer, focusing especially on non-cancer-related death.

Methods

Between January 2004 and March 2011, 1673 patients with lung cancer underwent surgical resection at our institution. Of these, we retrospectively examined 174 patients aged 80 years or older.

Results

Perioperative morbidity and mortality were 24.3% and 1.15%, respectively. Of 163 patients who were followed up completely, 78 (47.9%) died. The overall postoperative survival rate at 3 and 5 years was 63.6% and 48.3%, respectively. Almost half of the deaths were due to causes other than lung cancer recurrence, with respiratory disease accounting for the majority. We found that a low body mass index was a significant risk factor for death due to respiratory disease after lung cancer surgery in this patient cohort.

Conclusion

The overall survival rate of octogenarians undergoing lung cancer surgery is acceptable. However, because octogenarians with a low body mass index have a significantly higher risk of death due to respiratory disease, surgeons and pulmonologists should take this into account when performing postoperative follow-up in these patients.

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.

Urine creatinine-based estimates of fat-free mass in community-dwelling older persons: the Rancho Bernardo study

OBJECTIVES

To determine whether a previously developed and externally validated equation using common variables (demographics and weight) that are important determinants of muscle mass to estimate 24-hour urine creatinine excretion rate (eCER) is associated with muscle mass and whether spot urine creatinine (UCr) provides similar estimates of muscle mass.

DESIGN

Observational cross-sectional cohort study.

SETTING

The Rancho Bernardo Study, San Diego, California.

SUBJECTS

A total of 1,371 Caucasian, middle class, community-dwelling older adults.

INTERVENTION

Morning spot UCr and fat-free mass (FFM) by dual-energy x-ray absorptiometry were measured. eCER was calculated: eCER (mg/day) = 879.89 + 12.51 × weight (kilogram) - 6.19 × age + 34.51 if black - 379.42 if female. Pearson correlation coefficients and linear regression were used to determine strengths of association of eCER and spot UCr with FFM.

RESULTS

Mean age was 70 years, and 58% were women. eCER was strongly correlated with FFM (r = 0.95, P < .001), a correlation that was superior to that of spot UCr (r = 0.40, P < .001).

CONCLUSIONS

An equation incorporating age, weight, sex, and race to estimate eCER is highly correlated with FFM in community-dwelling older persons and provides a more precise estimate than spot UCr. A simple screening tool for sarcopenia in older persons may allow interventions to maintain or improve muscle mass. Future studies should evaluate whether eCER predicts sarcopenia-related frailty and mortality in older persons.

Should pulse oximetry be included in GPs' assessment of patients with obstructive lung disease?

OBJECTIVE

To explore the associations between decreased pulse oximetry values (SpO2) and clinical, laboratory, and demographic variables in general practice patients diagnosed with asthma or chronic obstructive pulmonary disease (COPD), including those with both COPD and asthma in combination.

DESIGN/SETTING

A cross-sectional study in seven Norwegian general practices of patients aged 40 years or over who were diagnosed by their general practitioner (GP) with asthma and/or COPD. The patients were examined during a stable phase of their disease. Patients diagnosed with COPD (including those with combined COPD/asthma) and those diagnosed with asthma only were analysed separately.

MAIN OUTCOME MEASURES

Decreased SpO2 values (≤ 95% and ≤ 92%).

RESULTS

Of 372 patients included (mean age 61.5 years, 62% women), 82 (22.0%) had SpO2 ≤ 95%, of which 11 had SpO2 ≤ 92%. In both asthma and COPD patients, SpO2 ≤ 95% was significantly associated with reduced lung function (spirometry), a diagnosis of coronary heart disease and older age (≥ 65 years). In the COPD group, haemoglobin above normal was associated with SpO2 ≤ 95%. These associations were confirmed by multivariable logistic regression, where FEV1% predicted < 50 was the strongest predictor of SpO2 ≤ 95% (odds ratio 6.8, 95% confidence interval 2.8-16.4).

CONCLUSION

Pulse oximetry represents a useful diagnostic adjunct for assessing the severity of obstructive pulmonary disease. Decreased pulse oximetry values in stable-phase patients with asthma and/or COPD should prompt the GP to consider revising the diagnosis and treatment and to look for co-morbidities. Key Points Despite its common use in general practice, the diagnostic benefits of pulse oximetry remain to be established. Decreased pulse oximetry values are associated with both reduced lung function (spirometry) and with a diagnosis of coronary heart disease. Decreased pulse oximetry values may reflect suboptimal treatment and/or undiagnosed comorbidity. Pulse oximetry may therefore be a useful measure in the follow-up of asthma and COPD patients in general practice.

Peak flow rate and death due to coronary heart disease: 30-year results from the Northwick Park Heart cohort study

Objective

Numerous studies have reported that chronic obstructive pulmonary disease or impaired lung function are associated with later coronary heart disease (CHD). However, it is unclear if lung function is an independent risk factor, as many of these studies have included only limited measures of other factors associated with CHD.

Methods

In total 2167 men of all ages in the first Northwick Park Heart Study were followed for a median of 30 years. Cox regression models were used to assess the relationship between peak flow rate (PFR) and CHD mortality adjusted for potential confounders measured at baseline. Analyses allowed for missing data, and secondary analyses for repeat measures on some men and competing risks of CHD death.

Results

There were 254 CHD deaths with some evidence of an association between PFR and CHD mortality. The adjusted HRs (95% CIs) from the lowest to the highest of four PFR quartiles were 1.53 (1.04 to 2.25), <430 L/min; 1.43 (0.99 to 2.08), 430 – <490 L/min; and 1.31 (0.93 to 1.86), 490 – <550 L/min; compared with the reference group of ≥550 L/min (trend test p=0.025). Other associations with CHD mortality were observed for systolic blood pressure (p<0.0001), body mass index (p=0.0002), smoking status (p=0.015), blood cholesterol (p=0.005), plasma fibrinogen (p=0.001) and high-risk ECG (p=0.021). There were no strong associations for factors V and VIII or platelet count.

Conclusions

After allowing for a range of other risk factors associated with CHD, there was only limited evidence of a relation between PFR and CHD mortality.

An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease

BACKGROUND

Limb muscle dysfunction is prevalent in chronic obstructive pulmonary disease (COPD) and it has important clinical implications, such as reduced exercise tolerance, quality of life, and even survival. Since the previous American Thoracic Society/European Respiratory Society (ATS/ERS) statement on limb muscle dysfunction, important progress has been made on the characterization of this problem and on our understanding of its pathophysiology and clinical implications.

PURPOSE

The purpose of this document is to update the 1999 ATS/ERS statement on limb muscle dysfunction in COPD.

METHODS

An interdisciplinary committee of experts from the ATS and ERS Pulmonary Rehabilitation and Clinical Problems assemblies determined that the scope of this document should be limited to limb muscles. Committee members conducted focused reviews of the literature on several topics. A librarian also performed a literature search. An ATS methodologist provided advice to the committee, ensuring that the methodological approach was consistent with ATS standards.

RESULTS

We identified important advances in our understanding of the extent and nature of the structural alterations in limb muscles in patients with COPD. Since the last update, landmark studies were published on the mechanisms of development of limb muscle dysfunction in COPD and on the treatment of this condition. We now have a better understanding of the clinical implications of limb muscle dysfunction. Although exercise training is the most potent intervention to address this condition, other therapies, such as neuromuscular electrical stimulation, are emerging. Assessment of limb muscle function can identify patients who are at increased risk of poor clinical outcomes, such as exercise intolerance and premature mortality.

CONCLUSIONS

Limb muscle dysfunction is a key systemic consequence of COPD. However, there are still important gaps in our knowledge about the mechanisms of development of this problem. Strategies for early detection and specific treatments for this condition are also needed.

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.

Particulate air pollution and mortality in a cohort of Chinese men

Few prior cohort studies exist in developing countries examining the association of ambient particulate matter (PM) with mortality. We examined the association of particulate air pollution with mortality in a prospective cohort study of 71,431 middle-aged Chinese men. Baseline data were obtained during 1990-1991. The follow-up evaluation was completed in January, 2006. Annual average PM exposure between 1990 and 2005, including TSP and PM10, were estimated by linking fixed-site monitoring data with residential communities. We found significant associations between PM10 and mortality from cardiopulmonary diseases; each 10 μg/m(3) PM10 was associated with a 1.6% (95%CI: 0.7%, 2.6%), 1.8% (95%CI: 0.8%, 2.9%) and 1.7% (95%CI: 0.3%, 3.2%) increased risk of total, cardiovascular and respiratory mortality, respectively. For TSP, we observed significant associations only for cardiovascular morality. These data contribute to the scientific literature on long-term effects of particulate air pollution for high exposure settings typical in developing countries.

The association between BMI and COPD: the results of two population-based studies in Guangzhou, China

BACKGROUND AND OBJECTIVE

An association between chronic obstructive pulmonary disease (COPD) and low body mass index (BMI) has been well established in cross-sectional studies. However, there have been few cohort studies investigating this issue. We therefore aimed to address this gap.

METHODS

Two population-based studies, a cross-sectional study including 1818 subjects and a subsequent 4-year cohort study consisting of 759 individuals without COPD, were conducted in Guangzhou, China. Every subject was 40 years old or older at the time of recruitment and completed questionnaire interviews, anthropometric measurements and spirometry testing. As a follow-up, each subject underwent annual pre-bronchodilator spirometry testing. Subjects with a pre-bronchodilator FEV1/FVC <0.7 were required to undergo post-bronchodilator spirometry testing. Subjects with a post-bronchodilator FEV1/FVC <0.7 were diagnosed with COPD.

RESULTS

Compared to subjects with normal BMI (18.5 to 23.9 kg/m(2)), those with low BMI (<18.5 kg/m(2)) had a higher prevalence of COPD (21.1% vs. 7.5%), with an adjusted OR of 2.75 [95% confidence intervals (CI): 1.69 to 4.47]. Both low BMI and obese (≥ 28.0 kg/m(2)) subjects had lower FEV1 after adjustment. This association was further confirmed in the cohort study; non-COPD subjects with low BMI at baseline were more likely to develop COPD (RR = 2.88, 95% CI: 1.06 to 7.85), independent of smoking status and other confounders.

CONCLUSIONS

Low BMI was not only a systemic consequence of COPD but also an important risk factor for the development of COPD, which raises the possibility that early intervention in subjects with low BMI may reduce the incidence of COPD.

Pathophysiology of muscle dysfunction in COPD

Muscle dysfunction often occurs in patients with chronic obstructive pulmonary disease (COPD) and may involve both respiratory and locomotor (peripheral) muscles. The loss of strength and/or endurance in the former can lead to ventilatory insufficiency, whereas in the latter it limits exercise capacity and activities of daily life. Muscle dysfunction is the consequence of complex interactions between local and systemic factors, frequently coexisting in COPD patients. Pulmonary hyperinflation along with the increase in work of breathing that occur in COPD appear as the main contributing factors to respiratory muscle dysfunction. By contrast, deconditioning seems to play a key role in peripheral muscle dysfunction. However, additional systemic factors, including tobacco smoking, systemic inflammation, exercise, exacerbations, nutritional and gas exchange abnormalities, anabolic insufficiency, comorbidities and drugs, can also influence the function of both respiratory and peripheral muscles, by inducing modifications in their local microenvironment. Under all these circumstances, protein metabolism imbalance, oxidative stress, inflammatory events, as well as muscle injury may occur, determining the final structure and modulating the function of different muscle groups. Respiratory muscles show signs of injury as well as an increase in several elements involved in aerobic metabolism (proportion of type I fibers, capillary density, and aerobic enzyme activity) whereas limb muscles exhibit a loss of the same elements, injury, and a reduction in fiber size. In the present review we examine the current state of the art of the pathophysiology of muscle dysfunction in COPD.

Body mass index and mortality in chronic obstructive pulmonary disease: a meta-analysis

Background

The association between body mass index (BMI) and mortality in patients suffering from chronic obstructive pulmonary disease (COPD) has been a subject of interest for decades. However, the evidence is inadequate to draw robust conclusions because some studies were generally small or with a short follow-up.

Methods

We carried out a search in MEDLINE, Cochrane Central Register of Controlled Trials, and EMBASE database for relevant studies. Relative risks (RRs) with 95% confidence interval (CI) were calculated to assess the association between BMI and mortality in patients with COPD. In addition, a baseline risk-adjusted analysis was performed to investigate the strength of this association.

Results

22 studies comprising 21,150 participants were included in this analysis. Compared with patients having a normal BMI, underweight individuals were associated with higher mortality (RR  = 1.34, 95% CI  = 1.01–1.78), whereas overweight (RR  = 0.47, 95% CI  = 0.33–0.68) and obese (RR  = 0.59, 95% CI  = 0.38–0.91) patients were associated with lower mortality. We further performed a baseline risk-adjusted analysis and obtained statistically similar results.

Conclusion

Our study showed that for patients with COPD being overweight or obese had a protective effect against mortality. However, the relationship between BMI and mortality in different classes of obesity needed further clarification in well-designed clinical studies.

The efficacy of spirometry as a screening tool in detection of air flow obstruction

BACKGROUND/OBJECTIVES

In developing countries, spirometry has not been considered a part of routine medical check-up. The purpose of the study was to establish the usefulness of spirometry as a primary screening tool in detecting air flow obstruction (AFO) during routine medical check-up (RMC).

METHODS

This was a hospital based, retrospective, non-randomized case series study of 3696 participants, who presented to hospital for routine medical check-up. All subjects were assisted at the Pulmonary Medicine Department, from January 2003 till December 2008 who, having met other inclusion criteria, underwent spirometry. Data were analyzed using proportion, group means, standard deviations and Pearson Chi Square test.

RESULTS

The overall yield from spirometry in detecting AFO was 211 patients (5.7%); 174 males (6.1%) and 37 females (4.4%) (P=0.158, Pearson Chi Square test). Greater age at presentation and BMI correlated significantly with AFO in the target group (P=<0.001; P=<0.005) respectively. Dyspnoea was the most frequent symptomatology observed in those diagnosed with AFO.

CONCLUSION

These results suggest that spirometry during RMC for all persons can detect a significant number of patients with AFO particularly among the middle and older age groups with a low BMI.