Associations Between Air Pollution and Hospitalization of Patients with Chronic Obstructive Pulmonary Disease in Kashi, China: A Time-Stratified Case-Crossover Study
Aug 2026· International Journal of COPD· Vol 21· 0 citations· 27 references
Medicine
TL;DR
PM2.5, PM10, NO2, and CO exposures were associated with COPD hospitalization in Kashi, precautionary measures should be taken with a focus on vulnerable subgroups, to control hospitalization for COPD associated with air pollutants.
Abstract
Objective To investigate associations between air pollutants and hospitalization of patients with chronic obstructive pulmonary disease (COPD) in Kashi, and to identify susceptible populations. Methods We conducted a retrospective study of COPD patients in Kashi between 2012 and 2022. Daily pollutant concentrations were matched to residential addresses for individual exposure assessment. A time-stratified case-crossover design with conditional logistic regression was used to evaluate associations between pollutants and COPD hospitalization. Stratified analyses were performed by age, gender, smoking history and hospitalization season. Sensitivity analysis was conducted by excluding hospitalizations during the COVID-19 pandemic to test result robustness. Results A total of 68,482 patients were included. The strongest significant association between particulate matter (PM10) and COPD hospitalization was identified at lag day 4, particulate matter (PM2.5), PM10, nitrogen dioxide (NO2) and carbon monoxide (CO) exposures generally had relationships of COPD hospitalization [OR (95% CI): 1.015 (1.002–1.032), 1.008 (1.002–1.016), 1.034 (1.008–1.067), and 1.034 (1.005–1.065), respectively]. Individuals who are young, patients with a history of severe acute exacerbations, farmers, smokers, and individuals admitted in cooler seasons may be particularly susceptible. Sensitivity analyses omitting COVID-19 cases showed barely significant associations for PM2.5, PM10 and NO2, with CO displaying only a faint, non-significant relationship. Conclusion PM2.5, PM10, NO2, and CO exposures were associated with COPD hospitalization in Kashi, precautionary measures should be taken with a focus on vulnerable subgroups, to control hospitalization for COPD associated with air pollutants.
Short-term exposure to PM2.5, PM10, SO2, NO2, and CO was associated with increased AECOPD hospitalization risk, with nonlinear, lagged, and cumulative effects, and older adults and females may be more susceptible to ambient air pollution.
Huixia Shi, Jiajun Li, Boyan Li et al.· Medicine· 0 citations
This study examines the long-term associations between ambient air pollutants and the burden of major respiratory and infectious diseases in this geographically sensitive region. A retrospective analysis was conducted using ICD-10-coded hospital records of patients diagnosed with asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and tuberculosis from January 2020 to June 2026. These data were integrated with in situ air quality measurements, including PM10, PM2.5, and SO2, as well as satellite-derived Aerosol Optical Depth (AOD) from MODIS. Disease incidence was stratified by year, sex, and age groups (0–85+ years) to assess demographic susceptibility patterns. Respiratory diseases constituted a substantial public health burden over the study period. Asthma showed a marked female predominance (≈29,700 females vs. ≈16,000 males) and a bimodal age distribution with peaks in early childhood (0–5 years) and mid-adulthood (35–50 years). COPD was predominantly observed in males (≈8300 males vs. ≈5500 females), with a higher median age range (≈67–70 years). Bronchitis exhibited a similar bimodal pattern, disproportionately affecting both pediatric and elderly populations, while overall case numbers declined over time. Tuberculosis incidence was approximately threefold higher in males than females, with notable age-related divergence, affecting younger females (≈30–32 years) and middle-aged males (≈42–45 years). The findings suggest a spatial–temporal correspondence between elevated pollutant concentrations and respiratory disease prevalence in the Iğdır Basin. The observed sex- and age-specific disparities underscore the potential value of region-specific environmental health strategies, strengthened air quality management, and continuous epidemiological surveillance in enclosed basin environments.
Melahat Batu Ağırkaya, Fatma Şencan, Mehmet Ali Çelik· Pollutants· 0 citations
BACKGROUND
The association between air pollutants and mortality from chronic kidney disease (CKD) remains to be further investigated. This study aims to examine the impact of air pollutant exposure on CKD mortality in individuals.
METHODS
This study utilized an individual-level, time-stratified case-crossover design to evaluate the association between short-term exposure to air pollutants (PM2.5, SO2, O3, and NO2) and mortality from CKD. The deceased population was identified from the mortality surveillance data of the Zhejiang Provincial Center for Disease Control and Prevention. For each decedent, we collected air pollutant concentrations on the day of death (case day) and on matched control days within the same month. This design inherently controls confounding factors such as age, place of residence, and seasonality.
RESULTS
The study found that short-term exposure to all four air pollutants was associated with an increased risk of CKD mortality. The excess risk (ER) per interquartile range (IQR) increase in pollutant concentrations was evaluated across different lag periods. Using multi-day moving average lags (calculated as the mean exposure from the current day up to the specified preceding day), the most prominent ERs were observed for PM2.5 at lag02 (ER: 15.16%, 95% CI: 12.69-17.68), SO2 at lag03 (ER: 8.80%, 95% CI: 5.95-11.72), O3 at lag01 (ER: 5.67%, 95% CI: 2.07-9.39), and NO2 at lag03 (ER: 13.66%, 95% CI: 9.12-18.39). After adjusting for interactions with other pollutants, the associations for SO2 and PM2.5 remained significant. Additionally, the study found that this association was influenced by factors such as marriage, and season (cold vs. warm).
CONCLUSIONS
This study revealed a significant association between short-term exposure to air pollutants and CKD mortality in the population of Zhejiang Province. These findings provide novel evidence for understanding the impact of environmental factors on kidney disease and suggest a need for governmental authorities to enhance the monitoring and control of air pollution to mitigate the health burden on the elderly.
P. Dai, Xiaoyan Zhou, Weiwei Gong et al.· BMC Nephrology· 0 citations
Short-term absolute changes in ambient air pollution levels may result in disease events such as depression, whereas evidence from large-scale epidemiological studies has been insufficient. A time-stratified case-crossover study was performed to investigate the associations between air pollution increases between neighboring days (APINs, generated as the differences in absolute air pollution concentrations on the current days minus those on the previous days) and morbidity risks of depression based on hospital admission and outpatient visit data from 239 Chinese cities of prefecture-level or above during 2013-2017. Daily absolute concentrations of particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM2.5), particulate matter with an aerodynamic diameter ≤ 10 μm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO) and ozone (8 h O3) were obtained, and conditional logistic regression models were used to evaluate the associations between absolute concentrations and APINs of major air pollutants with morbidity risks of depression. A total of 330,610 hospital admissions and 3,726,390 outpatient visits for depression were included. Per interquartile range (IQR) increase in APINs of major air pollutants at lag 0-3 were associated with increases ranging from 0.59% (0.06%, 1.13%) (8 h O3) to 1.66% (1.09%, 2.22%) (NO2) in hospital admissions for depression; and with increases ranging from 0.42% (0.15%, 0.68%) (8 h O3) to 0.85% (0.56%, 1.14%) (NO2) in outpatient visits for depression, which were robust to adjustments for absolute concentrations of major air pollutants (with the exception of 8 h O3). This study provides novel evidence that short-term absolute increases in air pollution levels are associated with elevated risks of depression, which is worth consideration in future disease prevention practices.
Yating Ma, Chenlu Yang, Lijun Bai et al.· Ecotoxicology and Environmen...· 0 citations
OBJECTIVES
This study aimed to evaluate the associations of air pollution with disease activity and flare rate in patients with rheumatoid arthritis (RA).
METHODS
This prospective cohort study included patients with RA who were treated at a tertiary medical centre in South Korea between January 2021 and December 2024. Air pollution exposure was estimated using monthly mean concentrations of 6 air pollutants (sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide, particulate matter [PM]10, and PM2.5). Disease activity and flares were recorded longitudinally at each outpatient visit. Associations between air pollution and RA disease activity or flare were analysed using linear and logistic generalised estimating equations, adjusting for demographic characteristics, serologic status, medication use, socioeconomic factors, and meteorological variables. As a sensitivity analysis, a case-crossover design using daily air pollutant concentrations preceding each visit was applied, with conditional logistic regression to assess within the same patient.
RESULTS
A total of 12,583 outpatient visits from 1070 patients were analysed. Among 6 pollutants, PM2.5 was significantly associated with an increased risk of flare (adjusted odds ratio [OR]: 1.113 [95% CI: 1.017-1.218]) and with higher Disease Activity Score based on 28 joints (DAS28) with C-reactive protein (CRP), Clinical Disease Activity Index, 28-tender joint count, and 28-swollen joint count. In addition, the association between PM2.5 and DAS28-CRP was more pronounced among women and nonsmokers. In the case-crossover analysis, prolonged cumulative exposure to PM2.5 over >2 weeks was associated with an increased risk of RA flare.
CONCLUSIONS
Exposure to air pollutants, particularly PM2.5, was associated with increased RA disease activity and flare risk. Further studies are warranted to determine whether improving air quality can reduce disease activity in patients with RA.
Sung Cheol Jung, Jeffrey R. Curtis, Seojin Yang et al.· Annals of the Rheumatic Dise...· 2 citations
BACKGROUND
Air pollution is an established risk factor for cardiovascular and metabolic diseases, but evidence on chronic kidney diseases (CKD) remains limited.
OBJECTIVE
We aim to examine the association between long-term exposure to air pollutants and CKD incidence.
METHODS
We followed 24,581 female nurses from the Danish Nurse Cohort, recruited in 1993 or 1999, for their first-ever hospital contact with a primary or secondary CKD diagnosis until 2018. We estimated annual mean levels of particulate matter with a diameter < 2.5 µm (PM2.5) and 10 µm (PM10), nitrogen dioxide (NO2), and black carbon (BC) at nurses' residential addresses using the DEHM/UBM/AirGIS modeling system. We used Cox regression models to examine the association of 14-year running means of air pollutants with CKD incidence and to explore the effect modification of this association by lifestyles.
RESULTS
Over 521,211 person-years of follow-up, 429 nurses developed CKD. We found positive associations of modest magnitude between long-term exposure to air pollutants and CKD, with hazard ratios (95% confidence intervals) per interquartile range: 1.18 (0.93-1.50) per 2.86 µg/m3 for PM2.5, 1.14 (0.93-1.40) per 3.33 µg/m3 for PM10, 1.13 (0.99-1.28) per 8.09 µg/m3 for NO2, and 1.09 (1.00-1.20) per 0.34 µg/m3 for BC. The associations between long-term exposure to NO2 and CKD incidence were greater in never smokers than in ever-smokers. Associations with NO2 and BC remained unchanged in two-pollutant models, whereas those with PM10 and PM2.5 attenuated.
SIGNIFICANCE
Our study adds important new findings to the growing evidence suggesting that air pollution may be associated with CKD incidence.
IMPACT STATEMENT
This study provides longitudinal evidence that long-term exposure to ambient air pollution contributes to chronic kidney disease (CKD) incidence, even in a relatively healthy occupational cohort and at comparatively low pollution levels. Although effect sizes were modest, consistent positive associations, particularly for NO2 and black carbon, highlight traffic-related pollution as a potential renal risk factor. Stronger associations among never-smokers suggest that environmental exposures may independently influence kidney health. These findings reinforce the need to integrate air pollution into CKD risk assessment and prevention strategies. Strengthening air quality policies and reducing long-term residential exposure could help lower CKD burden and protect kidney health at the population level.
Gonzalo Hevia-Ramos, Jiawei Zhang, Stephane Tuffier et al.· Journal of Exposure Science...· 0 citations