Mesothelioma risk and environmental exposure to asbestos: past and future trends in Japan.

Although asbestos has been widely distributed in the environment, health risks due to general environmental exposure to asbestos have not been estimated. Future mesothelioma risk from environmental exposure to asbestos in Japan was estimated by comparing historical exposure data and mortality attributed to environmental exposure. We developed an equation to estimate environmentally-attributable mesothelioma based on the US Environmental Protection Agency's model for occupational mesothelioma mortality. Based on our calculations, mesothelioma risks per year of exposure will reach peak levels in 2033 and range from 4.8 x 10(-6) to 1.1 x 10(-5). The number of deaths is estimated to range from 542-1276 in 2033. The cumulative number of deaths will reach around 17,000-37,000 in the years 1970-2070. Our estimation of risk approximately corresponded to observed risks. Past and predicted future disease suggest the need for social and medical support in these areas.