The results of the univariate analysis showed that in patients with positive lung nodules, the proportions of age, smoking or frequent passive smoking, significant psychological stress in the past year, occupational exposure (presence of air pollution in the work environment), presence of chronic lung disease, family history of lung cancer, and elevated levels of carcinoembryonic antigen were higher compared to patients with negative lung nodules. Here, CEACAM5 is linked to lung carcinoma.