The Occupational Studies Section supports and conducts epidemiologic studies of occupational groups to identify and clarify the role factors in the workplace play in the origin of cancer. During the past year several studies were completed on cancer risks among workers exposed to pesticides. A mortality study of farmers from Wisconsin noted excesses of cancers of the lymphatic and hematopoietic system, stomach, prostate and eye. Excess deaths from lymphatic cancer were noted among grain workers, particularly those from grain mills where pesticides are used to control insects. A case-control study in Kansas uncovered a striking dose-response between the risk of non-Hodgkin's lymphoma and number of days of use of herbicides, particularly 2,4-D that rose to over sixfold among farmers with 20 or more days of exposure. A study of industrial workers exposed to formaldehyde uncovered an excess of cancer of the nasopharynx that rose with increasing level of exposure among workers who were also exposed to formaldehyde-containing particulates and a 30% excess of lung cancer that was not associated with level of exposure. Industrial hygiene monitoring for formaldehyde in industry found eight-hour time-weighted averages below 2 ppm in most plants but higher levels occurred in areas where formaldehyde-containing particulates were present. Excesses of leukemia and brain cancer (predominantly gliomas) were seen among anatomists. A case-control study of nasal cancer in the Netherlands found that the will-known excessive risk of adenocarcinoma from exposure to wood dusts (16-fold) did not decrease for at least 15 years after termination of exposure. Annual increases in incidence of mesothelioma between 1973 and 1980 of approximately 12% remained after a histopathologic review by a panel of expert pathologists. A 10-fold excess of astrocytic brain cancer was associated with long-term employment in the electronics industry in a case-control located in Pennsylvania, New Jersey, and Louisiana. Workers producing ceramic plumbing fixtures exposed to talc had over twice the expected mortality from lung cancer.
