Hollings Cancer Center, Medical University of South Carolina, 86 Jonathan Lucas St, PO Box 250955, Charleston, SC 29425, USA. alberg@musc.edu

BACKGROUND: The objective of this study was to summarize the published literature concerning the epidemiology of lung cancer. METHODS: A narrative review of published evidence was conducted, identifying and summarizing key reports that describe the occurrence of lung cancer in populations and factors that affect lung cancer risk. RESULTS: In the United States, lung cancer remains the leading cause of cancer death in both men and women, even though an extensive list of modifiable risk factors has long been identified. The predominant cause of lung cancer is exposure to tobacco smoke, with active smoking causing most cases but passive smoking also contributing to the lung cancer burden. CONCLUSIONS: The reductions in smoking prevalence in men that occurred in the late 1960s through the 1980s will continue to drive lung cancer mortality rates downward in men during the first portion of this century, but rates in women have not yet begun to decrease. Fortunately, exposures to major occupational respiratory carcinogens have largely been controlled, but the population is still exposed to environmental causes of lung cancer, including radon, the second leading cause of lung cancer death.

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Observatoire Régional de la Santé PACA, INSERM UMR 379, 23 rue Stanislas Torrents, 13006 Marseille, France. verger@marseille.inserm.fr

OBJECTIVES: To study physician barriers to workers’ compensation claims for asbestos-related cancers, focusing on smokers’ stigma and physicians’ speciality and role perception. METHODS: Cross-sectional telephone study of 486 randomly-selected general practitioners (GPs) and pulmonologists in south-eastern France. Standardised questionnaires explored their behaviour, attitudes and practices in the field of occupational health and their responses to a case vignette of a lung cancer patient with long-term occupational asbestos exposure. Randomised subgroups of GPs and pulmonologists heard alternative versions varying only as regards the worker’s smoking status. We studied factors associated with the recommendation that the case vignette patient file a compensation claim with simple and multiple logistic regressions. RESULTS: The response rate was 64.4% among GPs and 62.5% among pulmonologists. Recommending the filing of an occupational disease claim was significantly associated in multiple logistic regressions with speciality (OR 4.46; 95% CI 2.38 to 8.37, for pulmonologists vs GPs), patient’s smoking status (OR 3.15; 95% CI 2.11 to 4.70, for non-smokers vs smokers), physician’s workload (OR 1.83; 95% CI 1.17 to 2.88, for </=25 consultations per day vs >25) and role perception (OR 2.00; 95% CI 1.22 to 3.27, for those who considered completing occupational disease medical certificates to be part of their role vs those who did not). CONCLUSIONS: The results of this French study appear applicable to various countries and contexts. To make physicians and especially GPs more aware of occupational health and smoking stigma, officials and educators must give these topics higher priority during initial training and continuing medical education. Tools and equipment that take time constraints into account should be developed and disseminated to help physicians manage occupational diseases.

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Aarhus University Hospital, Department of Occupational Medicine, Aarhus, Denmark.

OBJECTIVES: Whether the elevated risk of lung cancer observed among welders is caused by welding emissions or by confounding from smoking or asbestos exposure is still not resolved. This question was addressed in a cohort with a long follow-up and quantified estimates of individual exposure to welding fume particulates. METHODS: Male metal workers employed at least 1 year at one or more Danish stainless or mild steel industrial companies from 1964 through 1984 were enrolled in a cohort. Data on occupational and smoking history were obtained by questionnaire in 1986. Welders in the cohort who started welding in 1960 or later (N=4539) were followed from April 1968 until December 2003, when information on cancer diagnosis was obtained from the Danish Cancer Registry. During the follow-up, 75 cases of primary lung cancer were identified. Lifetime accumulated exposure to welding fume particulates was estimated by combining questionnaire information and more than 1000 welding-process-specific measurements of fume particulates in the Danish welding industry. RESULTS: The standardized incidence ratio (SIR) for lung cancer was increased among the welders [SIR 1.35, 95% confidence interval (95% CI) 1.06-1.70)]. Among the stainless steel welders, the risk increased significantly with increasing accumulative welding particulate exposure, while no exposure-response relation was found for mild steel welders, even after adjustment for tobacco smoking and asbestos exposure. CONCLUSIONS: The study corroborates earlier findings that welders have an increased risk of lung cancer. While exposure-response relations indicate carcinogenic effects related to stainless steel welding, it is still unresolved whether the mild steel welding process carries a carcinogenic risk.

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School of Public Health, University of Sydney, NSW 2006, Australia.

Exposure-response relationships between the relative risk of lung cancer and quantitative measures of exposure to asbestos are available from a number of epidemiological studies. Meta-analyses of these relationships have been published by Lash et al. (1997) [Lash, T.L., Crouch, E.A.C., Green, L.C., 1997. A meta-analysis of the relation between cumulative exposure to asbestos and relative risk of lung cancer. Occup. Environ. Med. 54, 254-263] and Hodgson and Darnton (2000) [Hodgson, J.T., Darnton, A., 2000. The quantitative risks of mesothelioma and lung cancer in relation to asbestos exposure. Ann. Occup. Hyg. 44, 565-601]. In this paper, the risks derived in these meta-analyses have been compared. Lash et al., concentrated on process and found that the risk of lung cancer increased as the asbestos is refined by processing. Hodgson and Darnton concentrated on fibre type and found that the risk was highest for exposure to amphibole asbestos (crocidolite and amosite), lowest for chrysotile and intermediate for mixed exposure. Some of the differences between the conclusions from the two meta-analyses are a consequence of the choice of studies included. The range of asbestos types included in the studies in the analysis of Hodgson and Darnton was wider than that in Lash et al., enabling differences between fibre types to be analyzed more readily. There are situations where occupational exposure to chrysotile asbestos has shown no detectable increase in risk of lung cancer. Taconite miners have shown no increased risk of mortality due to lung cancer.

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Institute for Scientific Interchange (ISI) Foundation, Turin, Italy. fveglia@isi.it

BACKGROUND: There is uncertainty regarding the association of occupational exposures with lung cancer. We have studied the association between 52 high-risk job titles and lung cancer incidence in a large prospective study, with more than 200,000 participants followed for more than 6 years and 809 incident cases of lung cancer. METHODS: Hazard ratios and 95% confidence intervals were computed by the Cox proportional-hazard regression model, adjusting for country, age, sex, social class, diet, physical activity, and smoking habits. We used a CAREX-based job-exposure matrix to infer exposure to lung carcinogens. False-positive report probability was calculated as a measure of potentially false-positive results. RESULTS: Eighteen occupations, mainly related with agriculture, constructions, and metal processing, were associated with increased risk. In addition, incidence tended to increase with the number of hazardous jobs reported. When the occupations were classified according to the presumed exposure to specific carcinogenic agents, the hazard ratios were 1.5 (95% confidence interval = 1.2-1.9) for asbestos, 1.4 (1.1-1.8) for heavy metals, 1.4 (1.1-1.8) for polycyclic aromatic hydrocarbons, and 1.6 (1.2-2.1) for work-related environmental tobacco smoke. The estimated population attributable risk for employment in at least 1 at-risk job was 16% in men and 12% in women. CONCLUSIONS: This large prospective study suggests that exposure to occupational lung carcinogens is still a problem, with such exposures producing moderate to large increases in risk.

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