Beyond smoking status: risk factors for pulmonary nodules ≥5 mm in a Chinese community screening program

Community screening for pulmonary nodules in China primarily targets heavy smokers despite regional variation in smoking prevalence and environmental exposures. Few studies have assessed questionnaire-derived smoking and non-smoking factors in relation to low-dose computed tomography (LDCT) detected pulmonary nodules while accounting for smoking status.

To examine LDCT detected pulmonary nodules ≥5 mm across different smoking groups and to identify associated risk factors within high-risk individuals for lung cancer in a Chinese community screening cohort.

This retrospective study analyzed data from a government-led community screening initiative in Zhuhai, China. Baseline screening records from 2021-2023 were used. High-risk individuals for lung cancer were identified using a standardized lung cancer risk-scoring system and advised to undergo low-dose computed tomography (LDCT). After data cleaning and restriction to participants with confirmed LDCT completion and uploaded LDCT findings, 5,414 participants were included. Multivariable logistic regression models assessed associations between demographic, smoking-related, lifestyle, environmental, familial, and clinical factors and LDCT detected pulmonary nodules ≥5 mm, overall and by smoking status.

Pulmonary nodules ≥5 mm were detected in 1,117 of 5,414 participants (20.6%). Detection was highest among never smokers (802/3,447, 23.3%), followed by former smokers (140/800, 17.5%) and current smokers (175/1,167, 15.0%). In the overall model, former smokers (aOR = 0.742, 95% CI: 0.593-0.928) and current smokers (aOR = 0.619, 95% CI: 0.503-0.762) had lower odds of nodules ≥5 mm than never smokers. Passive smoking exposure was associated with higher odds of nodules ≥5 mm (aOR = 1.257, 95% CI: 1.056-1.496), whereas irregular chest pain (aOR = 0.709, 95% CI: 0.573-0.877) and persistent cough (aOR = 0.806, 95% CI: 0.653-0.996) were associated with lower odds. Exploratory stratified analyses showed that subgroup-specific signals were mainly concentrated among never smokers.

Among LDCT completed individuals at high risk for lung cancer, pulmonary nodules ≥5 mm were detected in one fifth of participants, especially among never smokers; passive smoking was positively associated with detection, while symptom and lung related history indicators showed inconsistent patterns. Community screening should strengthen risk assessment beyond active smoking, refine questionnaire-based indicators, and validate this strategy through multi region collaboration.