Formaldehyde, cancer, and social class.

Formaldehyde has been shown to cause nasal cancer in rats exposed by inhalation. Neoplasia did not develop at locations distant from sites of initial contact, a finding consistent with the chemical's high reactivity and rapid detoxification. The recently published report of the Consensus Workshop on Formaldehyde, however, drew particular attention to small excesses of malignant brain tumors and leukemia among causes of death in several groups of professionals in the U.S. and U.K. who use formaldehyde to preserve human tissues (1). Despite deficits of these diseases in mortality studies of for-maldehyde-exposed industrial workers from the same countries, the report implied that the excesses of brain cancer and leukemia in the professional groups may have been occupationally caused. When evaluating the significance of the mortality experience of occupational groups, it is important to consider the possible effects of social class. Small disease excesses or deficits may have resulted from lifestyle characteristics of the persons under study as reflected by their social class and not from occupational exposures or "the healthy worker effect." As indicated in Table 1, in the U.S. and U.K. mortality from brain cancer and, to a lesser degree, leukemia, has consistently increased with elevation in social class. An analysis of deaths of white males , 20 years of age during 1950-1981 in the state of Washington, U.S., noted proportional mortality ratios (PMRs) of 138 and 128 for brain cancer and leu-kemia, respectively, among professional and technical workers. These compared to PMRs of 96 and 87 in operatives , and 75 and 66 among laborers (2). The dichotomy between mortality from brain cancer and leukemia in formaldehyde-exposed professionals (social class I) and workers (operatives and laborers, Table 1. Mortality ratios of men by social class. Population description Social class High Low Place Race Age Years Ratioa I II III IV V Ref.