[Fraction analysis of the involvement of multiple risk factors in the etiology of lung cancer: risk factor interactions in a case-control study for lung cancer in females].

A 1:1 matched case-control study of etiologic fraction (EF) of female lung cancer was conducted in Guangdong Province. 200 female cases with primary lung cancer were selected and 200 female controls matched by age, area of residence and education from five hospitals. Multiple conditional logistic regression analysis turned out that passive smoking from spouse, bad ventilation in kitchen, liking for pickles or salted fish, history to chronic bronchitis, family history of tumour, pulmonary tuberculosis, taking oral contraceptive were the independent risk factors of female lung cancer (OR = 2.16-40.55, P < 0.05). EF of the independent risk factors were 0.535, 0.432, 0.252, 0.124, 0.115, 0.072, 0.069 respectively. The interactions between passive smoking from spouse and risk factors which included taking oral contraceptive, family history of tumour, bad ventilation in kitchen, history of pulmonary tuberculosis, liking for pickles or salted fish were analyzed. The result revealed that EF (AxB) (aetiologic fraction attributable to interaction) were 0.848, 0.499, 0.479, 0.416, 0.346 respectively. The interaction index were 0.906, 0.543, 0.578, 0.427, 0.441. These findings indicate passive smoking from spouse, particularly those had a history of taking oral contraceptive, increases the risk of female lung cancer.