Malignant Pleural Mesotheliomas: An Environmental Health Risk in Southeast Turkey

Accessible online at: www.karger.com/journals/res Natural asbestos deposits pose a health hazard not to be neglected in some European and non-European countries. According to our information, about 113 asbestos deposits are known in Turkey, of which 65% contain chrysotile, 39% tremolite and 1% crocidolite. Whereas industrial exploitation is only of minor importance, domestic and agricultural use play a more important role, the farming of asbestos-containing land and the domestic use of asbestos-containing white-wash, roofing, cleaning liquids and toothpaste causing sometimes considerable exposure to asbestos dusts. In recent years, the high hazards in the respective areas of Southern Turkey have led to an intensive public information campaign organized by the medical professions and the authorities. As a result of these campaigns, Senyigit et al. [1] register a decline in the incidence of mesothelioma in a number of affected areas. Thus, the rise in frequency of mesothelioma in regions previously not known in this respect is a marked signal for investigating the danger potential and health hazards. In their paper on the incidence of malignant pleural mesothelioma and on CT findings in 117 patients, published in this issue of Respiration, Senyigit et al. [1, 2] approach this subject in a remarkable way. The results and conclusions drawn from investigations over a comparatively long period of time are convincing. Regarding the purely environmental exposure, the investigated patient collective has a very homogeneous structure. The explanation for the nearly equal sex ratio (male:female 1:1.3) in its differentiation from the ratio after occupational exposure is plausible. The statements concerning a possibly higher incidence than the calculated one reflect the general problems connected with patient inherent and demographic factors. The long latency periods until the development of malignant mesothelioma put into perspective, for the time being, the assessment of preventive measures. The varying carcinogenicity of the inhaled asbestos fiber types is mentioned as one very important factor. In the past, the views concerning tremolite especially varied considerably. Now, however, it is widely believed that the carcinogenic potency of tremolite is much higher than that of chrysotile. The knowledge of natural asbestos fibre types is of decisive importance in cases where environmental exposure has to be differentiated from occupational exposure. We are frequently confronted with such issues of differentiation, these cases include Turkish patients developing mesothelioma after their emigration to Germany. All patients are comparatively young (!50 years) at the time of falling ill, compared to 160 years after purely occupational exposure. The share of females affected is markedly