A comparative study of the risk factors for lung cancer in Guangdong, China

A case-control study involving 390 lung cancer cases, matched 1:1 with controls, was carried out in Guangdong Province to compare risk factors for different histopathologic types of lung cancer in both sexes. Female and male lung cancers appear to differ in epidemiological characteristics, pathologic types, and risk factors. The 291 lung cancer cases in males were predominantly squamous cell lung carcinoma (squamous cell carcinoma/adenocarcinoma = 1:0.5), whereas the 99 female lung cancer cases were predominantly adenocarcinoma (squamous cell carcinoma/adenocarcinoma = 1:2.7). The age at which lung cancer was first diagnosed was lower for females than for males (P < 0.0001). Single-factor conditional logistic regression analysis showed an association of lung cancer with family history of tumors, family history of lung cancer, history of chronic bronchitis/emphysema, history of tuberculosis, history of other lung disease, smoking, exposure to environmental tobacco smoke (ETS) in the home and in the workplace, being professional drivers, use of oral contraceptives, and consumption of pickled and salted fish (P < 0.05). Further multivariate logistic regression analysis showed that family history of tuberculosis, history of chronic bronchitis/emphysema, family history of tumors, smoking, exposure to ETS in the home and in the workplace, and consumption of pickled and salted fish were independent risk factors for lung cancer. Using log-linear model analysis, it was confirmed that lung cancer had significant interactions with chronic bronchitis/emphysema, exposure to ETS, history of tuberculosis and smoking. Smoking, however, could only explain 1/5 of the incidence of female lung cancers. Family history of lung cancer and the use of oral contraceptives were related to lung cancer in women. Except for a weak relationship with history of chronic bronchitis/emphysema, adenocarcinoma was found to have no association with the other risk factors.