CT-based Airway changes after long-term smoking cessation in the general population

Previous research has demonstrated improvements in CT-derived bronchial parameters in the first years after smoking cessation. This study investigates the association between longer smoking cessation duration and bronchial parameters in lung-healthy and lung-unhealthy ex-smokers from the general population.
Materials and Methods
We conducted a cross-sectional analysis using low-dose CT scans of ex-smokers from the general population with at least 10 pack-years from the ImaLife study, a sub study within the Lifelines cohort. Participants ⩾45 years who completed a lung-function test were recruited for low-dose CT imaging. We divided them into lung-healthy and lung-unhealthy based on spirometry, self-reported diagnosis and imaging signs of respiratory disease. Bronchial parameters Pi10, wall thickness, luminal area and wall area percent (WAP) were obtained using a previously validated method. Multivariable linear regression (MLR) was used to evaluate the independent associations between smoking cessation duration and bronchial parameters, adjusting for sex, age, height, weight, and pack-years.
Results
The study included 1,869 ex-smokers; 1,421 (76 %) were classified as lung-healthy (58 % men, mean age 64.2 ± 9.8 years, pack-years 16.5 [12.5–23.3], smoking cessation duration 20.0 [14.0–29.0] years) and 448 (24 %) as unhealthy (56 % men, mean age 66.1 ± 10.5 years, pack-years 18.2 [13.4–25.2], smoking cessation duration 20.0 [13.8–29.0] years). In the lung-unhealthy group, individuals with a longer duration of smoking cessation had a lower WAP compared to those with a shorter cessation duration (−0.528 % per 10 years, p = 0.005). In contrast, in MLR no significant associations were observed for the lung-healthy group..
Conclusions
In individuals with respiratory conditions, longer smoking cessation duration is related to a decrease in wall area percent of the bronchial walls. The results suggest the potential for improvements in airway health when people quit smoking, warranting further investigation with longitudinal studies.