Potential risk of asbestos exposure among Japanese general population: Japanese general screening study for asbestos-related diseases (JGSARD).

Abstract

1530 Background: The number of patients with pleural mesothelioma and lung cancer associated with asbestos exposure has recently been increasing in Japan. The aim of this study was to evaluate the results of screening for asbestos-related diseases in a group of Japanese general population. Methods: This prospective study was approved by the institutional review board. From 2006 to 2008, 9810 subjects (5283 men and 4527 women; mean age, 57 years) underwent chest radiography and low-dose CT examinations in 26 institutions in Japan. Among them, 6286 (64.1%) subjects underwent subsequent CT examinations after 2 years of interval. Clinical information such as histories of smoking and asbestos exposure was reviewed. Images were interpreted independently by 15 experienced pulmonologists or chest radiologists. Results: The history of asbestos exposure was definitely present in 1253 (12.8%) subjects, possibly present in 2058 (21.0%), and absent in 6499 (66.2%). On chest radiograph, pleural plaque and thickening were seen in 61 (0.6%) and 65 (0.6%) subjects, respectively. On low-dose CT, pleural plaque and thickening were identified in 264 (2.7%) and 245 (2.5%) subjects, respectively, and non-calcified pulmonary nodule/mass was seen in 1003 (10.2%). Furthermore, lung cancer was identified in 29 (0.3%) subjects. The history of asbestos exposure was not confirmed in 77 out of 264 subjects (29.2%) having pleural plaques on low-dose CT. Based on the logistic regression analysis, pleural plaque on low-dose CT was significantly correlated with male, age more than 60 years, smoking, and a history of asbestos exposure. Especially, total residential period in asbestos factory area as well as asbestos exposure work period showed significantly increased relative risk every 10 years. Similarly, lung cancer was significantly correlated with age more than 60 years, a history of asbestos exposure, and presence of pleural plaques. Conclusions: Our results indicate the presence of pleural plaques on low-dose CT among Japanese general population is closely associated with potential risk of asbestos exposure. However, about 30% of such subjects are not aware of a history of asbestos exposure.