The Etiological Study On Lung Cancer In Non-smoking Women

Objective Lung cancer is a serious health problem in public, the morbidity and the mortality have been increasing rapidly. The mortality of lung cancer in women increases year by year. It is shown that most of the cases are non-smoking women, and the risk factors still are unclear. This study is to explore the effect of pollution in room, passive smoking and other factors on the incident of lung cancer, and to study the relationship between food intake frequency and female lung cancer, and the relationship between nutrients and female lung cancer. Methods We selected 618 newly diagnosed cases with primary lung cancer. The controls were selected with random in the general population in urban districts. Using the same questionnaire two trained interviewers performed this interview face-to-face. The content of questionnaire includes the character of demography, the history of passive smoking, the exposed history of cooking fume, the fuel exposure, the exposed history of coal fume, the history of using "Kang", the history of previous diseases of lung, the cancer history of relatives and the occupational history, and the food intake frequency. The data were input and checked by professional staffs, the statistical analyses were performed with SPSS statistical package. The conditional logistic regression model were usedto estimate the odds ratios (OR) and 95% CI for different risk factors and test the statistical significance of their associations with lung cancer. Results The passive smoking in childhood was related with the lung cancer of non-smoking women and OR was 1.81. The OR of passive smoking in occupational positions and in family was 1.11 and 0.74 respectively. The exposure to the cooking fume was of great significance and OR was, 3.18(95% CI 2.55-3.97). The relationship between coal fume and lung cancer is significant and OR was 2.56(95%CI 1.83-4.55). Previous diseases of lung including tuberculosis, chronic bronchitis, asthma, pneumonia, emphysema were strongly associated with the lung cancer and OR were 1.80 (95%CI 1.43-2.27). The family history of cancer including the family history of cancer and the malignant tumors history in the first relatives have effect on the increase of the incident of lung cancer, but there was no statistical significance. The OR was 2.09 and 2.46 respectively. After adjusting other factors the OR and 95%CI: cooking fume was 4.09(95%CI 2.58-6.48), the previous lung diseases was 2.18 (95%CI 1.18-4.04), the history of family was 2.85(95%CI 1.56~5.19).We didn't find any association between the coal fume, the history of using "Kang" etc and the incidence of lung cancer. This study also showed that the intake of milk can increase the risk of lung cancer, the OR was 2.04, the intake of eggplant and garlic can decrease risk of lung cancer, the OR was 0.41 and 0.22 respectively. After adjusting thefactor of smoking, the association between vegetables intake and lung cancer still occurs. The result of nutrients analysis showed that the amount of intake (3-carotene, retinal, fiber, vitamin C was difference in cases and controls. By trend test the OR value for (3-carotene was 1.19, 0.84, 0.62, for retinal 0.91, 0.76, 0.63, for fiber 0.88, 0.46, 0.56, for vitamin C 0.97, 0.75. 0.62. According to the intake amount, the results indicated significantly dose-effect relationship between the nutrients and lung cancer risk for niacin 0.72, 0.62, 0.68 respectively. After adjusting cigarette smoking with conditional logistic model, the protective effects of the nutrients to lung cancer were still acted, the OR value for (3-carotene was 0.88, 0.69, 0.61, for retinal 0.91, 0.75, 0.68, for fiber 0.83, 0.56, 0.46, for vitamin C 0.88, 0.68, 0.60, for niacin 0.96, 0.79, 0.73 respectively. For caloric, water, protein and fat intake, there was not showed relationship between lung cancer risk and the intake amounts. Conclusion Passive smoking in childhood, cooking fuel exposure, previous diseases of lung including tuberculosis and family history of lung cancer are risk factors of non-smoking lung cancer. The intake of milk can increase the risk of lung cancer, and the intake of eggplant and garlic can decrease risk of lung cancer. P-carotene, retinal, fiber, vitamin C and niacin were protective factors for lung cancer.