Genetic susceptibility to asbestos-related fibrotic pleuropulmonary changes.

The objective of this study was to determine whether genetic polymorphisms in enzymes that metabolise oxidative agents modify the individual susceptibility to developing asbestos and smoking-related pleuropulmonary changes. Nine polymorphisms of six genes (EPHX1, GSTM1, GSTM3, GSTP1, GSTT1 and NAT2) were genotyped from 1,008 Finnish asbestos-exposed workers. The genotype data were compared to signs of lung fibrosis and pleural thickenings, as well as with total lung capacity, single-breath diffusing capacity of the lung for carbon monoxide (D(L,CO)) and specific diffusing capacity (expressed as D(L,CO) per unit of alveolar volume (V(A))). The GSTT1 deletion polymorphism was associated with fibrotic changes (p=0.003), and decreased D(L,CO) (p=0.02) and D(L,CO)/V(A) (p=0.002), and the GSTM1 deletion polymorphism was associated with the greatest thickness of pleural plaques (p=0.009). On further analysis, the GSTT1 null genotype was found to pose over a three-fold risk for severe fibrotic changes (OR 3.12, 95% CI 1.51-6.43), and around two-fold risks for decreased D(L,CO) (OR 1.77, 95% CI 1.06-2.95) and D(L,CO)/V(A) (OR 2.37, 95% CI 1.33-4.23). In addition, the GSTM1 null genotype showed an elevated risk (OR 1.36, 95% CI 1.03-1.80) for thicker pleural plaques. Our data suggest that inherited detoxification capacity may affect the development and severity of asbestos and smoking-related nonmalignant pulmonary changes.

Chest CT screening of asbestos-exposed workers: lung lesions and incidental findings.

The objective of the present study is to determine the feasibility of chest computed tomography (CT) in screening for lung cancer among asbestos-exposed workers. In total, 633 workers were included in the present study and were examined with chest radiography and high-resolution CT (HRCT). A total of 180 current and ex-smokers (cessation within the previous 10 yrs) were also screened with spiral CT. Noncalcified lung nodules were considered positive findings. The incidental CT findings not related to asbestos exposure were registered and further examined when needed. Noncalcified lung nodules were detected in 86 workers. Five histologically confirmed lung cancers were found. Only one of the five cancers was also detected by plain chest radiography and three were from the group of patients with a pre-estimated lower cancer probability. Two lung cancers were stage Ia and were radically operated. In total, 277 individuals presented 343 incidental findings of which 46 required further examination. Four of these were regarded as clinically important. In conclusion, computed tomography and high-resolution computed tomography proved to be superior to plain radiography in detecting lung cancer in asbestos-exposed workers with many confounding chest findings. The numerous incidental findings are a major concern for future screenings, which should be considered for asbestos-exposed ex-smokers and current smokers.

Computed tomography of asbestos-related pleural abnormalities.

OBJECTIVES: To study the observer agreement in several asbestos-related pleural abnormalities and to define criteria to discriminate between pleural changes in workers with occupational disease, and those in controls. METHODS: Pleural abnormalities in spiral computed tomography of 602 construction workers with asbestosis or bilateral pleural plaques and 49 controls were reviewed by three radiologists using structured forms. RESULTS: Intra- and inter-observer agreement (weighted kappa) was 0.4 or better with regard to the calcification, extent and thickness of pleural disease. These factors all correlated positively with the duration of asbestos exposure. There were significant differences in these pleural changes between the workers (mean extent per side 83 cm(2)) and controls (mean extent per side 40 cm(2)). Of the controls, 84% showed pleural lesions with an estimated extent of 10 cm(2) or more, bilateral in 64%. The extent of 45 cm(2) in pleural disease was the best value for discriminating between the controls and diseased workers, with a sensitivity of 82% and a specificity of 66%. The degree of pleural calcification, however, was the best discriminator between these groups, but quantitative methods are necessary for its use in the diagnostics of individuals. CONCLUSIONS: The extent, calcification and thickness were well-repeatable indicators of benign pleural pathology and thus their use in future classification systems in computed tomography is recommended. In our material, the extent of 45 cm(2) and the degree of calcification were helpful in discriminating between pleural changes in workers with occupational disease, and those in controls who also presented marked pleural pathology.

Smoking and exposure to tobacco smoke at medium-sized and large-scale workplaces.

BACKGROUND: The objective of the present study was to assess the smoking prevalence of workers, the attitudes toward smoking, and exposure to environmental tobacco smoke (ETS) in different work environments. METHODS: A questionnaire survey and indoor air quality (IAQ) measurements including the concentration of gaseous nicotine in indoor air were performed in 10 medium-sized and large-scale workplaces representing industrial, service, and office environments. The questionnaire was distributed to all workers (n=1471) in 10 workplaces. IAQ measurements were performed in 4-7 locations in each workplace. RESULTS: Altogether 1027 (70%) employees, of whom 31% were women, responded to the questionnaire. Prevalence of daily smokers was 28.3% (32.3% for men and 22.9% for women). The prevalence was highest among workers in the service sector (32.7%) and lowest in offices (21.6%). Among smokers, 86% of men and 75% of women smoked inside the building. Exposures greater than one hour to ETS were highest in industry (66.3%) and lowest in services (42.6%). Non-smokers complained more often than the regular smokers about the spreading of tobacco smoke to non-smoking areas, and they felt that workplace smoking was a significant discomfort. Mean concentration of nicotine was highest in service environments (3.0 microg/m(3)) and lowest in offices (0.6 microg/m(3)). CONCLUSIONS: According to the present questionnaire survey and IAQ measurements, smoking habits and exposure to tobacco smoke varied considerably depending on the position of the employees and the type of the workplace.