Demographic patterns for mesothelioma in the United States.

Incidence rates for pleural and peritoneal mesotheliomas in about 10% of the U.S. population were examined by various demographic characteristics based on 1973-84 data from the Surveillance, Epidemiology, and End Results Program. Although pleural mesothelioma was more common than peritoneal mesothelioma, both are rare diseases in this country. Pleural mesothelioma incidence rates among white males increased over time and were highest in seaboard areas where shipyards have been located (Seattle, San Francisco-Oakland, Hawaii). The significant secular change was attributed to both period (date of diagnosis) and cohort (date of birth) effects. Pleural mesothelioma incidence rates among white males were nearly 50% higher in the 1980-84 period compared to those in 1975-79; the cohort effect rose to a peak for the 1905-9 birth cohort and then declined. These effects probably reflect changes in asbestos exposure patterns in the past and more recent changes in clinical awareness and coding rules for mesothelioma. Geographic analysis of U.S. death certificates for pleural cancer among white males and females dying during 1968-78 indicated that mortality rates were significantly elevated in several areas that have had asbestos-manufacturing plants or shipyards. Analyses of mortality rates must be viewed with caution, since mesothelioma is considerably underreported on death certificates.