ABSTRACT
<p><b>BACKGROUND AND OBJECTIVE</b>The incidence of lung cancer in non-smokers is increasing in recent years. The aim of this investigation is to explore main risk factors of non-smoking primary lung cancers in Sichuan province in order to provide more accurate data for clinical.</p><p><b>METHODS</b>One hundred and fourty-five non-smoking pairs of cases and 145 of controls were matched by age and sex. The patients were newly-diagnosed definitely as primary lung cancer at West China Hospital of Sichuan University from March to December 2009.</p><p><b>RESULTS</b>Seventeen exposure factors were explored as epidemic agents for non-smoking lung cancer in Sichuan by using univariate analysis; mutivariate conditional Logistic regression analysis showed that passive smoking, moved into newly renovated homes over the past 10 years, family cancer history from second/ third-degree relatives, lack of emotion regulation, heavy work pressure and poor quality of sleep were main risk agents for the non-smoking lung cancer incidence with OR 2.267 (95% CI: 1.231-4.177), 5.080 (95% CI: 1.632-15.817), 7.937 (95% CI: 1.815-34.705), 2.491 (95% CI: 1.230-4.738), 5.769 (95% CI: 2.030-16.396), 2.538 (95% CI: 1.277-4.861), respectively. While higher body mass index, eating fruit and vegetable and regular participating in physical exercise might be protective factors with OR 0.419 (95% CI: 0.226-0.779), 0.344 (95% CI: 0.155-0.762), 0.507 (95% CI: 0.274-0.937), respectively.</p><p><b>CONCLUSION</b>The occurrence of non-smoking primary lung cancer associated with a variety of exposure factors including passive smoking, history of exposure to harmful environmental, family cancer history, mental and psychological factors in Sichuan Province.</p>