ENDEMIC PLEURAL PLAQUES AMONG THE INHABITANTS AROUND THE ASBESTOS MINES AND FACTORIES

Abstract

We have been conducting a lung cancer screening since 1986 to the inhabitants of almost all towns and cities of Kumamoto prefecture in Kyushu, Japan. In 1988, we found a high prevalence (41.5%) of cases with pleural plaque among the inhabitants of Matsubase town where our hospital is located. In this town, three asbestos mines and four factories were operating between 1883 and 1970. Asbestos ore was found to be an anthophyllite by analytical electron microscopy. Most cases were considered to be exposed environmentally, rather than occupationally. The age-adjusted rate and standardized mortality ratio of lung cancer were not higher than those in other cities and towns in Kumamoto prefecture. No case of malignant mesothelioma in this town has been confirmed during the past fifteen years, but further follow-up of these subjects are needed.