The impact of acute air pollution fluctuations on bronchiectasis pulmonary exacerbation: a case-crossover analysis

Abstract

In bronchiectasis, exacerbations are believed to be triggered by infectious agents, but often no pathogen can be identified. We hypothesised that acute air pollution exposure may be associated with bronchiectasis exacerbations.We combined a case-crossover design with distributed lag models in an observational record linkage study. Patients were recruited from a specialist bronchiectasis clinic at Ninewells Hospital, Dundee, UK.We recruited 432 patients with clinically confirmed bronchiectasis, as diagnosed by high-resolution computed tomography. After excluding days with missing air pollution data, the final model for particles with a 50% cut-off aerodynamic diameter of 10 µm (PM) was based on 6741 exacerbations from 430 patients and for nitrogen dioxide (NO) it included 6248 exacerbations from 426 patients. For each 10 µg·m³ increase in PM and NO, the risk of having an exacerbation that same day increased significantly by 4.5% (95% CI 0.9-8.3) and 3.2% (95% CI 0.7-5.8) respectively. The overall (lag zero to four) increase in risk of exacerbation for a 10 μg·m increase in air pollutant concentration was 11.2% (95% CI 6.0-16.8) for PM and 4.7% (95% CI 0.1-9.5) for NO Subanalysis showed higher relative risks during spring (PM 1.198 (95% CI 1.102-1.303), NO 1.146 (95% CI 1.035-1.268)) and summer (PM 2.142 (95% CI 1.785-2.570), NO 1.352 (95% CI 1.140-1.602)) when outdoor air pollution exposure would be expected to be highest.In conclusion, acute air pollution fluctuations are associated with increased exacerbation risk in bronchiectasis.

<p>Acute Effects of Air Pollution on Hospital Admissions for Asthma, COPD, and Bronchiectasis in Ahvaz, Iran</p>

“…The risk of exacerbation of bronchiectasis significantly increased in Dundee, with increase in PM 10 and NO 2 , on the same day; and the effect of NO 2, was stronger in spring. 13 In Beijing, China, exposure to PM 2.5 , PM 10 , NO 2 , SO 2 , and CO was significantly related to increased admissions for upper respiratory tract infections, acute bronchitis, pneumonia, and acute bronchiectasis; and PM 10 , SO 2 , CO, and O 3 was also associated with outpatient admissions due to acute exacerbation of COPD and asthma. 12 Researchers think air pollutants have complex effects on the airways of respiratory patients, and cause inflammation, mucosal edema, and toxicity.…”

“…[5][6][7] The effects of air pollution on the respiratory system include increased respiratory symptoms, decreased lung function, and increased incidence of chronic cough and bronchitis. 8,9 Epidemiological and clinical studies show that in children and adults, increased hospital admissions, lung diseases, lung cancer, 10 bronchiectasis, [11][12][13][14] respiratory infection, pulmonary embolism, asthma, 2,6,[15][16][17][18] and chronic obstructive pulmonary diseases (COPD) 9,[19][20][21][22][23] are affected by air pollution.…”

The microbiome in bronchiectasis

“…Disease-associated exacerbations have a major effect on patient healthcare costs as well as quality of life due to increased lung damage and mortality risk [10][11][12][13]. Microorganisms such as Pseudomonas aeruginosa and, to a lesser extent, other Gram-negative and Gram-positive microorganisms identified in culture, have been linked to disease progression, poor clinical outcomes in bronchiectasis and driving airway neutrophil-mediated inflammation [14][15][16][17][18][19].…”

The biology of pulmonary exacerbations in bronchiectasis

“…Despite these recommendations, other potential causes of exacerbations in bronchiectasis have not thoroughly been investigated and comorbidities could also play a relevant role, as is the case in other respiratory diseases [29,30]. For example, the association between high levels of environmental pollution and exacerbations suggests a role for pollutants in increasing airway inflammation, suppressing host immunity and disturbing the biofilm, thus leading to an exacerbation [31]. Gastro-oesophageal reflux disease is one of the most important comorbidities in bronchiectasis and has been associated with an increased number of exacerbations and hospitalisations [30,32,33].…”