The Influence of Cigarette and Cannabis Smoking on Severity of AATD Related Lung Disease

Abstract

Abstract Background: Alpha-1 Antitrypsin Deficiency (AATD) is a genetic disorder associated with an increased risk of developing chronic obstructive pulmonary disease (COPD), particularly in individuals exposed to environmental risk factors such as smoking behavior. Despite growing awareness, AATD remains underdiagnosed, and many affected individuals may initiate smoking before being aware of their genetic vulnerability. The aim of this project was to explore the relationship between tobacco and cannabis use and lung function in individuals diagnosed with AATD. Methods: This observational cohort study used data from the UK AATD Registry. Variables included smoking status (categorized as current, ex-, or never smokers), cumulative tobacco exposure (pack-years), lung function measured by FEV₁% predicted, and annual exacerbation rates. A total of 1,480 individuals were initially available, 1,115 were enrolled in the analysis after excluding cases with missing key variables such as FEV₁% predicted. Descriptive statistics, non-parametric tests (Kruskal–Wallis), and correlation analyses (Spearman’s rank) were used to assess relationships. Results: Analysis of FEV₁% by smoking history groups revealed significant differences across groups (p < .001). Never-smokers had the highest mean FEV₁%, while ex-smokers had the lowest. A significant overall difference in exacerbation rates was also found between the groups (p = .017). Spearman’s correlation showed a statistically negative correlation between pack-years and FEV₁% (r = –0.278, p < .001). Descriptive statistics showed that among 18 cannabis users, the mean FEV₁% was 58.96%. Conclusion: This study reinforces the harmful effect of smoking on lung function in individuals with AATD. Both current and former smokers exhibited significantly reduced FEV% compared to never-smokers. While primary data on cannabis use suggest potential impairment, further research with larger and more detailed samples is required. These findings support prioritizing early smoking prevention and cessation strategies, particularly in AATD patients.