A Case-control Study On The Risk Factors Of Lung Cancer

[Objective] To investigate the risk factors for primary lung cancer in order to provide the basis for the prevention and control of lung cancer.[Methods] A 1:2 matched case-control study was carried out. The cases are the patients with the primary lung cancer diagnosed from public health surveillance areas in Zhejiang province between November 2005 and December 2008. Two neighborhood control matched for age and sex, et al., were enrolled. The case and control were interviewed about the exposure information of related factors using the questionnaire. Statistical analysis of single- factor, multivariate conditional logistic regressions were performed to screen the risk factors of lung cancer. The main factors were extracted by principal factor analysis and screened by multivariate conditional logistic regressions. The population attributable risks and interaction effects were also calculated. [Results] 1. General conditions: Body mass index (BMI) and average income per person were statistically significant to lung cancer; 2. Occupation and exposure history: the ORs to lung cancer of workers and farmers were 1.43 and 0.69, respectively. The construction and plastics industry workers and cooks were the hazard groups to lung cancer, the risk would increase 1.75 fold and 2.54 fold per working for 10 years in construction works and cooks, respectively; 3. Indoor and environmental factors: the ground which were wood and soil were risk factors and which was cement was protective factor. The area per person was negative to lung cancer. Using coal stove for heating, the fume in kitchen and surround air pollution were risk factors and using gas for cooking was protective factor to lung cancer; 4. Diet behavior: consumption of foods, such as eggs, fresh vegetables, garlic and sour food and cooking behaviors such as cold/raw and roast presented weak protective effect. Consumption of salty (such as salty vegetables, fish or meat), fumed (such as fumed fish or meat), pickled and drying food (such as pickle) were risk factors to lung cancer; 5. Life style and behaviors: the risk of smokers to suffer lung caner was 2.89 fold compared with non-smokers. The hazard to lung cancer was increased by the dose of the smoking. The risk would be reduced if smokers quitted smoking. The risk of non-smokers which were in passive smoking is 1.56 fold compared with which without passive smoking, The dose-response was observed between passive smoking and risk rate of lung cancer. The risk of drinking quitters to lung cancer was 2.16 fold to drinkers. And there might be some connections to lung cancer; 6. Psychological factors: type A character, weak emotion self-control ability, disharmony marriage, bad relationship, long-term depression and mental trauma history were risk factors of lung cancer; 7. Diseases and family history: respiratory diseases history was the risk factors of lung cancer, and risk of whom had the history of TB, COPD, emphysema, asthma, or pneumoconiosis were 2.04, 2.14, 2.71 and 2.00, respectively; 8. Female physiological factors: latter menarche and history of dysmenorrheal were the risk factors to lung cancer for women; 9. Multivariate analysis: the risk factors of male lung cancer were construction or plastic industry workers, cooks, pesticide contactors, wood or soil ground, surround air pollution, consumption of fume or pickled and drying food, smoking, bad emotion self-control ability and mental state, and history of mental trauma or TB, and the protective factors were higher BMI, average house area per person, consumption of sour food; feel kitchen fume heavy, consumption of pickled and drying food, bad relationship and mental state, tumor history in direct relatives and latter menarche were the risk factors in female, and higher BMI, high income and consumption of fresh vegetable were the protective factors; 10. Factor analysis: Factor 2 (consumption of fry, pickled and drying or salty food), Factor 3 (disharmony marriage and bad relationship), Factor 4 (respiratory disease history such as emphysema, asthma, and pneumoconiosis), Factor 5 (fume condition in kitchen), Factor 8 (occupational exposure such as working in pesticide factory), Factor 9 (mental trauma or other mental state), Factor 11 (smoking and drinking tea), Factor 12 (construction workers, dusty working environment and heating by coal stove) were risk factors to lung cancer, and Factor 6 (house ground made by cement), Factor 7 (consumption of eggs, fumed and roast food), Factor 10 (consumption of sour food and garlic), Factor 13 (house area per person) were protective factors; 11. Population attributable risks: male and female sum population attributable risks were 0.5250 and 0.4731, respectively; 12. Interaction effects: there was a significant positive multiplied model interaction effect between smoking and psychological factors in male lung cancer. The association strength sequence was that: bad mental state> mental trauma history>weak weak emotion self-control ability.[Conclusion] Multivariate combination results the incidence of primary lung cancer in Zhejiang province. It indicated that comprehensive interventions should be focus on smoking group, female which exposed to fume in kitchens, low income group, and psychological depression group to prevent lung cancer effectively.