Environmental pleural plaques in an asbestos exposed population of northeast Corsica

The purpose of this study was to determine whether the inhabitants of villages environmentally exposed to asbestos, in northeast Corsica, had a higher incidence of pleural plaques. X-rays were obtained from subjects aged over 50 yrs, with no occupational exposure to asbestos or history of pleural disease, in one village exposed to asbestos, Murato, and a nonexposed, control village, Vezzani. In addition, the mineral content of the air and parietal pleura of animals in the exposed zone was studied, using transmission electron microscopy. The incidence of bilateral pleural plaques in the exposed population was 41%, as compared to 7.5% in the nonexposed population (p < 0.00001). The levels of airborne tremolite were higher in Murato (6-72 ng.m-3) than in Vezzani (< 1 ng.m-3), but chrysotile levels were similar. Significant numbers of chrysotile and tremolite fibres were identified in the parietal pleura of animals from the exposed village. This study confirms the well-known correlation between bilateral pleural plaques and environmental exposure to low levels of asbestos.