Prospective clinical and radiologic study of zeolite-exposed Turkish immigrants in Sweden.

Ninety-four persons from the village of Karain, Turkey, now residing in Stockholm, were investigated clinically and radiologically. In this village, environmental exposure to erionite, a fibrous zeolite, occurs, and there is an extremely high risk of mesothelioma among the villagers. Since an earlier investigation of the cohort in 1980, another 4 young persons have fallen ill with malignant mesothelioma in this group, where the incidence thus approaches 1%/year and is the most common cause of death. Solitary pleural plaques were found in 6%, thickening of the interlobar pleura in 4% and other radiologic signs of affection of the pleura in 2%. Thickening of the interlobar fissures were observed in 1 patient as the first sign of mesothelioma which has remained asymptomatic until 1 year later. The comparatively low incidence of pleural lesions in the cohort is probably due to the low mean age (36 years). Further follow-up could give clues to the pathogenesis of malignant mesothelioma.