Malignant pleural mesothelioma from nonoccupational asbestos exposure in Metsovo (north-west Greece): slow end of an epidemic?

Inhabitants of the Metsovo area, north-west Greece have been exposed since childhood to inhalation of asbestos, from a material containing tremolite, used for whitewashing ("luto soil"). This has resulted in endemic pleural calcifications (47% of adult population) and increased incidence of malignant pleural mesothelioma (MPM). In 1987, we reported that the incidence of MPM between 1981-1985 was around 300 times higher than expected in a nonasbestos exposed population (seven cases in 5 yrs in a population of 4,000-5,000). The present study is an updated report regarding this "mesothelioma epidemic", in conjunction with the diminished use and final abandonment of "luto soil" in the early 1980s. It appears that the incidence of MPM in Metsovo has dropped considerably since our first report. Between 1985-1994, we diagnosed six such cases (incidence rate = 1.4 cases per 10,000 person-years), whilst between 1980-1984 eight cases had been diagnosed (incidence rate = 3.7 cases per 10,000 person-years). Although, because of the small number of cases, this did not reach statistical significance (p = 0.08), we note that the incidence is now considerably lower than before. Had it remained unchanged, we would have expected 17 cases of MPM instead of six. This drop follows the diminished use of "luto" whitewash (by 92% of the population in 1950 and only 18% in 1980). If we take into account a 30-40 year latency period for mesothelioma, we expect that the "Metsovo mesothelioma epidemic" will fade away by the year 2020-2030, since the material has not been used since 1985.