Decreasing Prevalence of Pleural Calcifications Among Metsovites With Nonoccupational Asbestos Exposure
An epidemiologic investigation performed in the Metsovo area of northwestern Greece (population around 5,000) 20 years ago revealed that more than half of the adult population presented with pleural calcifications (PCs). Soon after (from 1981 to 1985), in the same area a mesothelioma “epidemic” was observed (ie, an incidence 300-fold higher than expected). Both phenomena were attributed to “luto,” a whitewash containing tremolite, that was used by practically all Metsovites from 1940 to 1950 and was gradually abandoned. In 1950, it was still used by 88% of the population, in 1960 by 68%, in 1970 its use had dropped to 37%, and in 1980 to 15%. Now its use has been completely substituted for by modern materials. The incidence of mesothelioma in the area of Metsovo, following the fading use of luto, has dropped between 1985 to 1994 to one third of the original incidence.
It is well-established that both mesothelioma and PCs are the result of exposure to asbestos (eg. tremolite) and other asbestiform fibers like erion-ite. Silica, talc, mica, and other minerals also may cause PCs, but this may be due to contamination from asbestos. Therefore, it would be particularly interesting to examine the evolution of PC prevalence in the Metsovo area 20 years after the first epidemiologic investigation. The results of this study in parallel with the already established decrease of mesothelioma incidence would further elucidate the impact of the nonoccupational use of asbestos on the respiratory system. buy amoxil online
Materials and Methods
Three hundred seven chest roentgenograms (CXRs) were collected from the records (from 1998 to 2002) of Metsovo Health Center, “G. Hadjikosta” General Hospital, and Ioannina University Hospital. These CXRs belonged to inhabitants of the four villages (ie, Metsovo, Milea, Anilio, and Votonossi) where PCs were first observed from 1978 to 1982. As was done in the previous study, patients were classified into five age interval groups (Table 1).