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Background: The role of airway impairment assessed by impulse oscillometry (IOS) in patients with chronic obstructive pulmonary disease (COPD) remains unclear. Therefore, this study aimed to analyze the proportion and clinical characteristics of airway impairment assessed by IOS across COPD severities, and explore whether airway impairment is a subtype of COPD. Methods: This study was based on cross-sectional data from the ECOPD cohort in Guangdong, China. Subjects were consecutively recruited from July 2019 to August 2021. They filled out questionnaires and underwent lung function tests, IOS and computed tomography (CT). COPD was defined as post-bronchodilator forced expiratory volume in one second/forced vital capacity < lower limit of normal (LLN). Meanwhile, airway impairment was defined as IOS parameters > upper limit of normal or < LLN. On the one hand, Poisson regression was employed to analyze the associations between acute exacerbations of COPD (AECOPD) in the previous year and airway impairment. On the other hand, logistic regression was used to assess differences in CT imaging between patients with IOS parameters' abnormalities and patients with normal IOS parameters. Results: 768 COPD subjects were finally enrolled in the study. The proportion of airway impairment assessed by R5, R20, R5–R20, X5, AX, and Fres was 59.8%, 29.7%, 62.5%, 52.9%, 60.9% and 67.3%, respectively. Airway impairment assessed by IOS parameters (R5, R5–R20, X5, AX, and Fres) in patients with COPD was present across all severities of COPD, particularly in GOLD 3–4 patients. Compared with patients with normal IOS parameters, patients with IOS parameters' abnormalities had more respiratory symptoms, more severe airway obstruction and imaging structural abnormalities. Patients with IOS parameters' abnormalities assessed by R5 [risk ratio (RR): 1.58, 95% confidential interval (CI): 1.13–2.19, P = 0.007], R5–R20 [RR: 1.73, 95%CI: 1.22–2.45, P = 0.002], X5 [RR: 2.11, 95%CI: 1.51–2.95, P < 0.001], AX [RR: 2.20, 95%CI: 1.53–3.16, P < 0.001], and Fres [RR: 2.13, 95%CI: 1.44–3.15, P < 0.001] had a higher risk of AECOPD in the previous year than patients with normal IOS parameters. Conclusions: Airway impairment assessed by IOS may be a subtype of COPD. Future studies are warranted to identify the underlying mechanisms and longitudinal progression of airway impairment. [ABSTRACT FROM AUTHOR]

Background: There is increasing evidence for a possible association between chronic obstructive pulmonary disease (COPD) and the use of biomass fuels for cooking and heating in developing countries. Data on the prevalence of COPD and objective measurements of indoor pollution from biomass fuel have not been widely available from China. A study was undertaken to investigate the prevalence of COPD in two study communities in Guangdong province in China and to measure the association between COPD and indoor biomass fuel air pollution. Methods: A cluster disproportional random sampling survey was performed in populations aged over 40 years in urban (Liwang) and rural (Yunyan) areas in Guangdong, China. Spirometry was performed in all subjects and a post-bronchodilator ratio of the forced expirotory volume in 1 s to forced vital capacity of <0.70 was defined as COPD. Measurements of indoor and outdoor air pollutants were also performed in a random sample of households. Results: The overall prevalence of COPD in the two areas (Liwang and Yunyan) was 9.4%. The prevalence of COPD in both the whole population and a subpopulation of non-smoking women in rural Yunyan was significantly higher than in urban Liwang (12.0% vs 7.4%, and 7.2% vs 2.5%, respectively). The use of biomass fuel was higher in rural Yunyan than in urban Liwang (88.1% vs 0.7%). Univariate analysis showed a significant association between COPD and exposure to biomass fuel for cooking. Multivariate analysis showed a positive association between COPD and urban/rural area (surrogate for fuel type and local exhaust ventilation in kitchen) after adjustment for sex, age group, body mass index, education, occupational exposure, respiratory disease in family, smoking status, life quality and cough in childhood; similar results were found in non-smoking women. Pollutants measurements showed that concentrations of carbon monoxide, particulate matter with an aerodynamic diameter ⩽ 10μm, sulphur dioxide and nitrogen dioxide in the kitchen during biomass fuel combustion were significantly higher than those during LPG combustion. Conclusions: Indoor pollutants from biomass fuels may be an important risk factor for COPD in rural South China. [ABSTRACT FROM AUTHOR]

While temperature changes have been confirmed as one of the contributory factors affecting human health, the association between high-frequency temperature variability (HFTV, i.e., temperature variation at short time scales such as 1, 2, and 5 days) and the hospitalization of chronic obstructive pulmonary disease (COPD) was rarely reported. To evaluate the associations between high-frequency temperature variabilities (i.e., at 1, 2, and 5-day scales) and daily COPD hospitalization. We collected daily records of COPD hospitalization and meteorological variables from 2013 to 2017 in 21 cities of Guangdong Province, South China. A quasi-Poisson regression with a distributed lag nonlinear model was first employed to quantify the effects of two HFTV measures, i.e., the day-to-day (DTD) temperature change and the intraday-interday temperature variability (IITV), on COPD morbidity for each city. Second, we used multivariate meta-analysis to pool the city-specific estimates, and stratified analyses were performed by age and sex to identify vulnerable groups. Then, the meta-regression with city-level characteristics was employed to detect the potential sources of the differences among 21 cities. A monotonic increasing curve of the overall exposure-response association was observed, suggesting that positive HFTV (i.e., increased DTD and IITV) will significantly increase the risk of COPD admission. Negative DTD was associated with reduced COPD morbidity while positive DTD elevated the COPD risk. An interquartile range (IQR) increase in DTD was associated with a 24% (95% CI: 12–38%) increase in COPD admissions. An IQR increase in IITV 0-1 was associated with 18% (95% CI: 7–27%) increase in COPD admissions. Males and people aged 0–64 years appeared to be more vulnerable to the DTD effect than others. Potential sources of the disparity among different cities include urbanization level, sex structure, industry structure, gross domestic product (GDP), health care services, and air quality. The increases of DTD and IITV have significant adverse impacts on COPD hospitalization. As climate change intensifies, precautions need to be taken to mitigate the impacts of high-frequency temperature changes. • Positive high-frequency temperature variation (HFTV) is associated with increased COPD morbidity while negative HFTV change decreases the COPD risk. • Males and people aged 0–64 years appear to be more vulnerable to the HFTV effects on COPD than others. • Heterogeneity in the HFTV effect is seen among different cities and linked to urbanization level, gender structure, industrial structure, etc. [ABSTRACT FROM AUTHOR]

To assess possible effect of air quality improvements, we investigated the temporal change in hospital admissions for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) associated with pollutant concentrations. We collected daily concentrations of particulate matter (i.e., PM 2.5 , PM 10 and PM coarse), sulfur dioxide (SO 2), nitrogen dioxide (NO 2), carbon monoxide (CO), ozone (O 3), and admissions for AECOPD for 21 cities in Guangdong from 2013 to 2017. We examined the association of air pollution with AECOPD admissions using two-stage time-series analysis, and estimated the annual attributable fractions, numbers, and direct hospitalization costs of AECOPD admissions with principal component analysis. From 2013–2017, mean daily concentrations of SO 2 , PM 10 and PM 2.5 declined by nearly 40%, 30%, and 26% respectively. As the average daily 8 h O 3 concentration increased considerably, the number of days exceeding WHO target (i.e.,100 μg/m³) increased from 103 in 2015–152 in 2017. For each interquartile range increase in pollutant concentration, the relative risks of AECOPD admission at lag 0–3 were 1. 093 (95% CI 1. 06–1. 13) for PM 2.5 , 1. 092 (95% CI 1. 08–1. 11) for O 3 , and 1. 092 (95% CI 1. 05–1. 14) for SO 2. Attributable fractions of AECOPD admission advanced by air pollution declined from 9. 5% in 2013 to 4.9% in 2016, then increased to 6. 0% in 2017. A similar declining trend was observed for direct AECOPD hospitalization costs. Declined attributable hospital admissions for AECOPD may be associated with the reduction in concentrations of PM 2.5 , PM 10 and SO 2 in Guangdong, while O 3 has emerged as an important risk factor. Summarizes the main finding of the work： Reduction in PM may result in declined attributable hospitalizations for AECOPD, while O 3 has emerged as an important risk factor following an intervention. ● The Guangdong province-wide interventional regulation on air pollution is effective. ● Association of air quality with hospital admissions for AECOPD is further confirmed. ● Reduction in PM and SO 2 may particularly lead to declined attributable AECOPD admissions. ● O 3 has emerged as an important risk factor for incidence of AECOPD. ● Principal component analysis is useful in determining major air pollutants. [ABSTRACT FROM AUTHOR]

The relation of acute fluctuations of air pollution to hospital admission for bronchiectasis remained uncertain, and large-scale studies were needed. We collected daily concentrations of particulate matter (PM), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and daily hospitalizations for bronchiectasis for 21 cities across Guangdong Province from 2013 through 2017. We examined their association using two-stage time-series analysis. Our analysis was stratified by specific sub-diagnosis, sex and age group to assess potential effect modifications. Relative risks of hospitalization for bronchiectasis were 1.060 (95%CI 1.014-1.108) for PM10 at lag0-6, 1.067 (95%CI 1.020-1.116) for PM2.5 at lag0-6, 1.038 (95%CI 1.005-1.073) for PMcoarse at lag0-6, 1.058 (95%CI 1.015-1.103) for SO2 at lag0-4, 1.057 (95%CI 1.030-1.084) for NO2 at lag0 and 1.055 (95%CI 1.025-1.085) for CO at lag0-6 per interquartile range increase of air pollution. Specifically, acute fluctuations of air pollution might be a risk factor for bronchiectasis patients with lower respiratory infection but not with hemoptysis. Patients aged ≥65 years, and female patients appeared to be particularly susceptible to air pollution. Acute fluctuations of air pollution, particularly PM may increase the risk of hospital admission for bronchiectasis exacerbations, especially for the patients complicated with lower respiratory infection. This study strengthens the importance of reducing adverse impact on respiratory health of air pollution to protect vulnerable populations. [ABSTRACT FROM AUTHOR]