The impact of smoking on the severity of COPD

Chronic obstructive pulmonary disease (COPD) is a major global health burden and remains strongly associated with tobacco exposure. This retrospective study evaluated the impact of active and past smoking on the clinical and functional severity of COPD within a Moroccan cohort. Data were collected from 70 patients managed in the pulmonology department of Mohammed VI University Hospital in Marrakesh from July 2024 to July 2025. The mean age was 64 years, with a marked male predominance (88%). Active smokers accounted for 67% of the cohort, with an average cumulative exposure of 36 pack-years. According to GOLD classification, severe and very severe stages (III–IV) were significantly more frequent among active smokers (74%) compared with former smokers (42%) and non-smokers (29%). Active smokers also exhibited higher dyspnea scores and a greater number of severe exacerbations requiring hospitalization. A significant correlation was observed between cumulative tobacco exposure and the degree of airflow limitation (p < 0.01), consistent with established evidence linking smoking intensity to accelerated FEV1 decline. The persistence of severe disease in some former smokers highlights the role of additional determinants, including genetic predisposition, occupational hazards, and environmental pollution—particularly biomass exposure, which may explain the 10% of non-smokers with COPD in this cohort. These findings underscore the need for systematic assessment of smoking status and exposure profiles in COPD management and emphasize the importance of smoking cessation, while encouraging further research integrating genetics, biomarkers, advanced imaging, and AI-based phenotyping to better understand COPD heterogeneity within the Moroccan population.