Analysis of current trends in United States mesothelioma incidence.

Mesothelioma incidence often is interpreted as an index of past exposure to airborne asbestos. The mesothelioma rate for US males exhibits an increasing trend throughout the 1970s and early 1980s. The trend has been attributed to occupational exposure in the shipbuilding industry during World War II, in manufacturing, and in building construction. Incidence data (1973-1992) from the Surveillance, Epidemiology, and End Results Program were used to investigate current trends in age-adjusted and age-specific mesothelioma rates. An age and birth-cohort model was used to project both lifetime probabilities of mesothelioma by cohort and the annual number of cases expected over the next 70 years. The current trend in female rates is flat (age-adjusted rate = 0.30 per 100,000). The estimated lifetime risk for females is 2.5 x 10(-4), independent of birth cohort. The projected average annual number of female cases is 500. For males, the age-adjusted mesothelioma rate is increasing solely due to the age group 75 years and over, albeit at a declining growth rate. Lifetime risk for males peaks at 2 x 10(-3) for the 1925-1929 birth cohort, then decreases to 5 x 10(-4) for the 1955-1959 birth cohort. The pattern of rates reflected in the age and birth-cohort model suggests a peak in the annual number of mesothelioma cases for males at 2,300 before the year 2000. The number of male cases then will drop during the next 50-60 years toward 500. These trends mirror the US trend in raw asbestos consumption and a reduction in workplace airborne asbestos levels.