A Study On The Associations Of Environmental Factors 、Patterns Of Pathological Types And Chlamydia Pneumonia Infection With Lung Cancer

[Objective]To investigate the main environmental risk factors of primary lung cancer in Han Chinese people in Fujian. To evaluate the association between type of cigarette and lung cancer by histological type. To explore the relation of chlamydia pneumonia infection with lung cancer. [Methods]1. A case-control study was conducted with 1421 patients and 1829 control subjects. Patients were recruited from the First affiliated hospital and the affiliated Union Hospital of Fujian Medical University and Fuzhou General Hospital with bronchoscopy and pathologic confirmation. All healthy controls were enrolled from hospital visitors and community population, and were frequency-matched to the cases on age(±2 year) at diagnosis and gender. Eligible subjects were personally interviewed using a questionnaire. To investigate the main environmental factors of lung cancer,a subgroup analysis by the status of smoking was conducted. To evaluate the associations between type of cigarette(filter/nonfilter) and pathological type of lung cancer, we further examined male current smokers(703 cases and 688 controls) for whom completed smoking histories regarding filter or nonfilter cigarettes were available.2. A matched case-control study was conducted to explore the association between chlamydia pneumonia and lung cancer. MIF assay was used to detect the antibodies of chlamydia pneumonia in serum.3. Dose response meta-analysis was conducted to systematically evaluate the dose response relation between the titers of chlamydia pneumonia and lung cancer. [Results]1. Among smokers, the risk factors for lung cancer included : polluted factory near residential area, insufficient ventilation indoor, never using range hood, pack-year of smoking, the history of pulmonary inflammatory diseases, the family history of lung cancer, BMI<18.5 and the protect factors were frequent intake of fruits,BMI≥24. The risk factors for lung cancer in non-smokers included : polluted factory near residential area, passive smoking(at home and workplace),cooking oil fume, insufficient ventilation indoor, no separate kitchen, the history of pulmonary inflammatory diseases, the family history of lung cancer. Frequent intake of fruits and tea drinking are protective factors of lung cancer among non-smokers.2. Lung adenocarcinoma was the most common pathologic type(46.5%), followed by squamous cell carcinoma(28.1%) and small cell carcinoma(7.8%) in our province.3. Compared with non-filter smokers, the wide use of filter cigarettes was related to the reduction of lung cancer( OR=0.50, 95%CI : 0.31-0.81) among male smokers.Among male smokers aged 60 years or more, filter cigarettes smokers displayed decreased the risk of adenocarcinoma and squamous cell carcinoma. However, under 60 years, no significant increase in risk of squamous cell carcinoma was observed among filter cigarettes smokers, whereas the adjusted OR indicated a non-significant reduction in risk of adenocarcinoma.4. Individuals seropositive for Cpn antibodies had significantly increased the risk of lung cancer. The OR for Cpn Ig G-Positive and Ig A-Positive was 1.90(95%CI:1.02-4.50)、2.39(95%CI:1.25-4.50),respectively. The subgroup analysis according to pathologic type showed that the Cpn infection was associated of lung adenocarcinoma and squamous cell carcinoma.5. The analysis of combined effects and interactions showed that there was a positive combined effect between smoking and Cpn Ig G/ Ig A antibodies.6. The pooled ORs for Cpn Ig A-Positive and Ig G-Positive was 2.03(95%CI:1.38-2.98)、1.77(95%CI:1.25-2.52),respectively. The dose response meta-analysis showed that there was a linear dose-response relation between Cpn-Ig A and lung cancer. [Conclusion]1. The risk factors of lung cancer among smokers were the same with non-smokers: Poor living conditions(air pollution, insufficient ventilation indoor, cooking oil fume), unhealthy behaviors(smoking, passive smoking, drinking), the history of pulmonary inflammatory diseases and the family history of lung cancer are identified as the risk factors of lung cancer.2. Lung adenocarcinoma was the most common pathologic type in our province. Compared with non-filter cigarettes smokers, the use of filter cigarettes reduced the risk for lung adenocarcinoma and squamous cell carcinoma among the older male smokers.However, compared with non-smokers, filter cigarettes increased the risk of lung cancer.3. Cpn infection was an independent risk factor and may act synergistically with smoking for lung cancer.