Cancers of the Nasopharynx and Oropharynx and Formaldehyde Exposure

Epidemiologic evidence on the relationship between formaldehyde exposure and cancer.

“…In the cohort study (28) relative risks for nasopharyngeal cancer increased steadily to 7.S-fold among workers who had cumulative exposure to formaldehyde of 2: 5.5 ppm-years and exposure to formaldehyde-containing particulates. No exposure-response relationship was found, however, among persons who were exposed to formaldehyde but not exposed to particulates.…”

“…In the studies of multiple plants in the United States (24,25,28,29,33,34) and Great Britain (23,68) excess mortality from lung cancer was not observed in all the plants. Among garment workers (34) in the United States, deficits were observed at two plants, whereas one had an excess.…”

Challenges to retrospective exposure assessment

“…There are, however, likely to be interactions among agents that are not structurally, or even physiologically, related that can also affect health outcomes. For example, in one study, formaldehyde by itself was not related to nasopharyngeal cancer, but in the presence of particulates an exposureresponse relationship was found (27). The difficulty for the investigator doing an assessment is that there are often hundreds of chemical and physical agents in a workplace to which a person can be exposed.…”

Quantification of historical exposures in occupational cohort studies

“…For example, in a study of formaldehyde workers, formaldehyde, formaldehyde-releasing particulates, and other particulates were present simultaneously in several of the companies under study (10). The authors did not find a risk for nasopharyngeal cancer from exposure to formaldehyde except when it was associated with particulates (11). Finally, it is important to evaluate exposure from all routes of exposure to determine their importance to total dose.…”