Interaction of smoking and aging on emphysema and small airways disease in asymptomatic healthy men by CT-based parametric response mapping analysis

Abstract

Aim: To explore whether small airway disease and emphysema were affected by the interaction between smoking and aging on chest computed tomography (CT) images of asymptomatic healthy men analysed using a quantitative imaging tool parametric response mapping (PRM).

Materials and methods: In this retrospective study, 95 asymptomatic healthy men underwent biphasic chest CT. The PRM classifies lung as a percentage of normal (PRM^Normal%), functional small airway disease (PRM^fSAD%), and emphysema (PRM^Emph%). The patients were divided into groups based on their age and smoking status. Multiple linear regression analysis was applied to explore the factors influencing lung injury. Simple effects analysis was performed to explore the interaction between different age groups and smoking status.

Results: The interaction between aging and smoking significantly affected PRM^fSAD% and PRM^Emph% (p<0.001). The age range 60-69 and smoking were associated with increased PRM^fSAD% and PRM^Emph% (p<0.05). Futher stratification into different age subgroups showed that smoking was associated with increased PRM^fSAD% and PRM^Emph% in the 50-59 year age group. Besides, smoking in the 50-59 and 60-69 years group was associated with decreased PRM^Normal%, while smoking in the 60-69 years group did not significantly influence the prevalence of PRM^fSAD% and PRM^Emph% (p>0.05).

Conclusions: PRM reveals the interplay between smoking and aging in the development of lung injury in asymptomatic healthy men. Aging and smoking are important factors of emphysema and small airway disease in the 50-69 years group. In the 60-69 years group, aging poses a greater risk of lung injury compared to smoking.