Continued progression of asbestos-related respiratory disease after more than 15 years of non-exposure.

BACKGROUND

Most studies on asbestos-related diseases describe the associations between exposure and disease and the factors influencing that association. It is recognized that there is a long latency period between exposure and disease, but the health status of affected individuals after long-term non-exposure is uncertain.

OBJECTIVES

To describe the changes in pulmonary function tests (PFTs) and computed tomographic imaging of the thorax over a 15 year period after cessation of exposure to asbestos in a cohort of Israeli power plant workers.

METHODS

Israeli power plant workers whose PFTs and thoracic CT imaging between 1993 and 1998 revealed asbestos-related disease underwent a second clinical, functional and imaging evaluation up to 15 years later. The two sets of results were compared.

RESULTS

Of the original cohort of 59 males, 35 were still alive and 18 of them agreed to take part in the current study. The mean length of their exposure was 30 +/- 10.06 years (range 7-43 years). Comparison of the initial and follow-up examination findings revealed a significant increase in calcification of the pleural plaques (from 37% to 66%, P = 0.008) and a deterioration in PFT results (P= 0.04). Of the 24 men who died, malignant disease was the cause of death in 53%, mostly in sites other than the respiratory system.

CONCLUSIONS

PFTs declined and CT findings worsened in subjects who were formerly exposed to asbestos and had not been exposed to it for over a decade. Continued monitoring of individuals exposed to asbestos, even decades after the cessation of exposure, is recommended.