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Published on: July 12, 2024
Association between air pollution and chronic cough: Evidence from a systematic review and meta-analysis of
Hyejun Kim1, Kefang Lai2, Tariq Cisse3
1Dalla Lana School of Public Health, University of Toronto, Ontario, Canada.
Background:
Chronic cough is a common and debilitating respiratory symptom, yet its association with air pollution remains insufficiently understood.
Methods:
We conducted a systematic review and meta-analysis of observational studies evaluating the association between air pollution and chronic cough. Searches of Medline, Embase, Scopus, and GeoBase were completed up to February 14, 2025. Studies were eligible if they reported quantitative associations between air pollution and exposures and chronic cough outcomes. Two reviewers independently screened studies, assessed quality, and extracted data. Random-effects models were used to estimate pooled odds ratios (ORs) with 95% confidence intervals.
Results:
Of 1250 articles screened, 53 studies were reviewed, and eight were included in meta-analysis. Pooled ORs per 10 μg/m3 increase in exposure were 1.10 (95% CI: 0.99-1.22) for PM2.5 and 1.04 (95% CI: 1.02-1.06) for NO2. Heterogeneity was low to moderate (I2: 18.9% for PM2.5; I2: 0.0% for NO2), and there was no evidence of publication bias (Egger's test p = 0.98 and 0.47, respectively). Stratified analyses revealed stronger associations in adults and males. Evidence on progression from chronic cough to more severe respiratory conditions was limited, highlighting a critical gap for evidence-informed clinical follow-up and public guidance to prevent progression.
Conclusion:
Our findings highlight that chronic cough is an overlooked consequence of air pollution exposure and emphasize the need for health care professionals to consider environmental factors when managing persistent cough. Strengthening air quality control and early detection strategies could help reduce the respiratory disease burden.
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