A 1:1 Matched Case-control Study On Risk Factors Of Primary Lung Cancer

Objective: To investigate the risk factors of Primary Lung Cancer and to provide better scientific basis for prevention of Primary Lung Cancer in Dalian.Methods: A 1:1 matched case-control study was carried out in Dalian including 200 cases and 200 controls in synthesize hospital of Dalian from March, 2007 to March, 2008. Cases and controls were requested must have lived in Dalian more than 10 years. Cases were chosen from in hospital patients who had diagnosed lung cancer in pathology nearly one or two years. According to the principle of 1:1 matched case-control study, controls were paired to cases with same sex, younger or older 3 years old, and controls must be patients with non-cancer and non- respiratory disease in the same period. The main contents of questionnaire included that general state of health, occupation, inhabited environment, life behavior, the history of disease, the family history of cancer, dietary habits, and psychological factor et.al. Data were input to the computer by the software of EXCEL 2003 and analyzed with Chi-square test, and the conditional Logistic regression by the softwares of SPSS 13.0 or SAS 8.2, then calculated the Odds Ratio and the 95% confidence. Results:1. There were no statistics difference between cases and controls in the aspect that educational level,marital status, blood type, the area of the family residence, family income and living expenses, and so on, but there were difference in the facet of per capita living space.2. There were difference in the facet that touching poisonous or noxious substance(OR=9.625,OR95%CI=4.647~19.934). With a develop- ped investgation, we found that asbestos, benzene, metallizer and dust were risk factors with primary lung cancer.3. In the dietary factor, eating fresh vegetables with green leaves, fresh fruit, fish, and garlic were protective factors, while seashell, smoked food, and animal fat were risk factors with primary lung cancer.4. Through reviewing the inhabited environment, we found that there were s significant difference between cases and controls in the aspect of whether the pollutional factory exist near the inhabited address, apparatus of high voltage around the workplace,apparatus of high voltage around the family residence, whether decorating the house during the near ten years, much more smog while cooking, smog irritating throat, using coal as the fuel. There were no statistics difference between the two group in the aspect of well water(OR=1.410, OR95%CI=0.936~2.126) and water from the water tank of the building (OR=, OR95%CI=0.398~6.974). Through investigating the behavior, we found that there were significant difference between the two groups in the aspect of smoking (OR=7.375), staying up late or all night (OR=1.793), and there were no statistical difference in the aspect of passive smoking(OR=1.292, OR95% CI=0.758~2.201), drinking alcoholic beverages(OR=1.379, OR95%CI= 0.855~2.225), drinking tea(OR=1.367, OR95%=0.853~2.189) between the two groups.5. There were statistical difference between the two groups in the aspect that the history of common cold, the history of checking chest in radioactive ray and the family history of cancer (OR=19.333).6. Through investigating the social psychic factor, we found that there were statistics difference between the two group in the aspect of experiencing the negative events, feeling pressure frequently, pessimistic way of handling affairs, Sulk, bad ability to regulate mood, disharmonious marriage life, having the experience of pressure during a long time. Good ability to communicate with others was the protective factor of lung cancer(OR=0.475,OR95%CI=0.306~0.740).According the multiple conditional logistic regression, there were significant difference between primary lung cancer and the factors include that touching poisonous or noxious substance, whether decorating the house during the near ten years, apparatus of high voltage around the family residence, the history of checking chest in radiation, having the experience of pressure during a long time, eating garlic, animal fat, Average smoking amount, and the family history of cancer. Except eating garlic is the protective factor, the others are the risk factors of primary lung cancer.Conclusion: The emergence of lung cancer is the result that many kinds of dangerous factors act on together, in Dalian. So, we should take the comprehensive measure to prevent lung cancer and reduce the morbidity .