Occupational risk factors for brain tumors. A case-referent death-certificate analysis

Numerous studies have suggested that employment in the oil refining and chemical manufacturing industries may be associated with excess brain tumor risk. A case-referent study was undertaken to evaluate brain tumor risk by occupation and industry in three geographic areas (northern New Jersey, Philadelphia, and the Gulf Coast of Louisiana) with a heavy concentration of these industries. Seven hundred and eighteen white men dying from brain tumor at age 30 years or older were ascertained from death certificates for 1978-1981. The referents were men who died of other causes, excluding epilepsy and stroke. Usual occupation and industry were obtained from the death certificates, and the maximum likelihood estimates of the relative risk were calculated for specific industries and occupations. Small nonsignificant excess risks of brain tumors were seen among persons whose usual employment was in the petroleum refining, electrical equipment manufacturing, health services, and educational services industries. Compared with other white-collar professionals, health diagnosticians, teachers, and artists/designers had a significantly elevated brain tumor risk. Among blue-collar workers, the only group with a significantly elevated brain tumor risk was precision metal workers, who are exposed to metal dusts and fumes and substances used as coolants, lubricants, and degreasers.