Tuberculosis and subsequent risk of lung cancer in Xuanwei, China.
ABSTRACT Tobacco and indoor air pollution from smoky coal are major causes of lung cancer in rural Xuanwei County, China. Tuberculosis has been suggested to increase lung cancer risk, but data from prior studies are limited. We conducted an analysis of data from a retrospective cohort study of 42,422 farmers in Xuanwei. In 1992, interviewers administered a standardized questionnaire that included lifetime medical history, including tuberculosis. Subjects were followed from 1976, with deaths from lung cancer ascertained through 1996. We used proportional hazards regression to assess the association between tuberculosis and subsequent lung cancer mortality. Tuberculosis was reported by 246 subjects (0.6%), and 2,459 (5.8%) died from lung cancer during follow-up. Lung cancer mortality was substantially higher in subjects with tuberculosis than in those without (25 vs. 3.1 per 1,000 person-years). The association was especially pronounced in the first 5 years after tuberculosis diagnosis (hazard ratios [HRs] ranging 6.7-13) but remained strong 5-9.9 years (HR 3.4, 95% CI 1.3-9.1) and 10+ years (HR 3.0, 95% CI 1.3-7.3) after tuberculosis. These associations were similar among men and women and among smoky coal users (70.5% of subjects). Adjustment for demographic characteristics, lung disease and tobacco use did not affect results. In Xuanwei, China, tuberculosis is an important risk factor for lung cancer. The increased lung cancer risk, persisting years after a tuberculosis diagnosis, could reflect the effects of chronic pulmonary inflammation and scarring arising from tuberculosis.
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ABSTRACT: Backgrounds: Mycobacterium tuberculosis has the ability to invade type II alveolar epithelial cells. As a result, the associations between invasion of alveolar epithelial cells and pathogenesis of lung infection seem strong.. Objectives: The aim of this study was to evaluate the presence of Mycobacterium tuberculosis in patients with lung cancer.. Materials and methods: This cross-sectional study was performed on samples collected from 380 patients with lung cancer referred to two state-run hospitals in Mashhad, Iran. Microscopic and cultural methods were utilized to assess the presence of Mycobacterium tuberculosis in the patient's specimens.. Results: The subjects were included 252 (66.3%) males and 128 (33.7%) females. Based on cultural and microscopic methods, Mycobacterium tuberculosis infection was observed in twenty six (6.8%) of cases.. Conclusion: This study showed the high prevalence of Mycobacterium tuberculosis among the patients with lung cancer; therefore, it seems that continuous surveillance is essential to monitor the Mycobacterium tuberculosis in the patients with lung cancer..Jundishapur Journal of Microbiology 01/2013; 6(3).
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ABSTRACT: In order to review the epidemiologic evidence concerning previous lung diseases as risk factors for lung cancer, a meta-analysis and systematic review was conducted. Relevant studies were identified through MEDLINE searches. Using random effects models, summary effects of specific previous conditions were evaluated separately and combined. Stratified analyses were conducted based on smoking status, gender, control sources and continent. A previous history of COPD, chronic bronchitis or emphysema conferred relative risks (RR) of 2.22 (95% confidence interval (CI): 1.66, 2.97) (from 16 studies), 1.52 (95% CI: 1.25, 1.84) (from 23 studies) and 2.04 (95% CI: 1.72, 2.41) (from 20 studies), respectively, and for all these diseases combined 1.80 (95% CI: 1.60, 2.11) (from 39 studies). The RR of lung cancer for subjects with a previous history of pneumonia was 1.43 (95% CI: 1.22-1.68) (from 22 studies) and for subjects with a previous history of tuberculosis was 1.76 (95% CI=1.49, 2.08), (from 30 studies). Effects were attenuated when restricting analysis to never smokers only for COPD/emphysema/chronic bronchitis (RR=1.22, 0.97-1.53), however remained significant for pneumonia 1.36 (95% CI: 1.10, 1.69) (from 8 studies) and tuberculosis 1.90 (95% CI: 1.45, 2.50) (from 11 studies). Previous lung diseases are associated with an increased risk of lung cancer with the evidence among never smokers supporting a direct relationship between previous lung diseases and lung cancer.PLoS ONE 01/2011; 6(3):e17479. · 4.09 Impact Factor