Prevalence of silicosis among Xiangyang-Chongqing Railway construction workers 40 years after dust exposure

Abstract

To investigate the prevalence of silicosis among workers who had participated in tunnelling of the Xiangyang-Chongqing Railway construction project and had returned to their home town and lived free of dust exposure for 40 years, and to provide a scientific basis for government decision. A total of 3417 civilian workers who had participated in tunnelling of the Xiangyang-Chongqing railway construction project during 1968 to 1972 were subjected to high-kV chest X-ray for primary examination. The suspected cases of silicosis underwent examination in Chongqing Center for Disease Control and Prevention for a confirmed diagnosis. Among the 3661 workers who were to undergo physical examination as planned, 3417 (93.34%) actually participated in this examination. The detection rate of silicosis was 9.34% (319/3417), including 192 cases of stage I, 116 cases of stage II, and 11 cases of stage III. No significant difference was found in average exposure time between different stages (F = 1.873, P > 0.05). The detection rate of silicosis was the highest among pneumatic drill workers, followed by tunnelling workers, blasters, supporting workers, and persons doing casual work. Significant difference was found in detection rate between different types of workers (χ² = 112.79, P < 0.05). Four decades after dust exposure, the prevalence of silicosis among workers who participated in tunnelling of the Xiangyang-Chongqing Railway construction project remains serious. Routine examination for silicosis, as well as documentation of patients' health status and follow-up investigation, should be carried out in these workers.