Bar-Shai, A; Greif, J; Topilsky, M; Schwarz, Y; Tiran, B
Follow up of asbestos related lung disease in a cohort of former power plant workers in Israel.
Bar-Shai A. Greif J. Topilsky M. Schwarz Y. Tiran B.
Department of pulmonary diseases, Tel Aviv Sourasky Medical Center, Israel
Background: The last decades of the 20th century saw a decrease in occupational exposure to asbestos in light of lessons learned regarding its detrimental effects on human health. However, the incidence of its long-term complications has risen, due to a typical latency period of 20-40 years between asbestos exposure and the manifestations of asbestos-related diseases. The long-term natural history of asbestos-related diseases has been well described, although the long-term risk of developing disease in at-risk individuals after cessation of exposure is less well established.
Objectives: The aim of this study was to describe the changes in pulmonary function tests (PFT) and imaging of the thorax over a 15-year period after cessation of exposure to asbestos, and to document the impact of the exposure on survival, in a cohort of Israeli power plant workers.
Methods: Between 1993 and 1998, fifty-nine former Israeli Electric corporation power plant workers presenting with respiratory complaints were examined by a pulmonologist and underwent pulmonary function test and thoracic imaging. Subjects who agreed to participate in the current follow-up study underwent a medical interview and physical examination, as well as repeated pulmonary function testing and thoracic imaging. The data was compared to their first examinations.
Results: Of the original cohort of 59 men, 23 (39%) were deceased. Among the causes of death, (35%) had died of lung disease (24% lung cancer, 11% interstitial lung disease). Moreover, survival was lower in subjects, which had initially presented with abnormal pulmonary function tests (p=0.04). Of the surviving 35 subjects, eighteen consented to take part in the follow-up study. On comparison of the initial and follow-up examinations, we found an increase in the incidence of calcified pleural plaques (37% to 66%, p=0.008), and deterioration in pulmonary function tests (p=0.045).
Conclusions: In this cohort of former power plant workers, pulmonary function test deteriorated and the CT scan findings worsened although the asbestos exposure had ceased more than 15 years earlier. The documented progression, mainly in deterioration of pulmonary function and appearance (or worsening) of pleural changes, even without significant parenchymal involvement, supports continued monitoring of workers, with a previous risk of exposure to asbestos, even decades after the cessation of exposure.
