Several case-control studies and an analysis of a large NCI industrial cohort have found an association between formaldehyde exposure and nasopharyngeal cancer, although some other studies have not. Data from extended follow-up of the NCI cohort found that the number of nasopharyngeal carcinomas observed in earlier reports persisted.
Influence of Formaldehyde on Funeral Directors
Several NCI studies of anatomists, preservatives and other professionals who may be exposed to formaldehyde at work have shown that these individuals have an increased risk of leukemia and brain cancer compared with the general population. However, these studies did not describe specific work practices and exposures. A case-control study of NCI in funeral industry workers characterized formaldehyde exposure and also revealed an association between increased formaldehyde exposure and myeloid leukemia mortality. In a study of funeral workers who died between 1960 and 1986, researchers compared those who died from hematopoietic and lymphoma to those who died from other brain tumors. Cancers of the hematopoietic or blood system, such as leukemia, occur in the blood or bone marrow. Lymphomas occur in tissues or organs that produce, store, and carry white blood cells to fight infections and other diseases. People who had been embalmed and were presumed to have the most exposure to formaldehyde had the highest risk of developing myeloid leukemia. It is not associated with other cancers of the hematopoietic and lymphatic systems or with brain cancer.
Formaldehyde and Industrial Workers
An earlier analysis of the NCI cohort found an increase in lung cancer mortality among 清甲醛industrial workers compared with the general U.S. population. However, lung cancer mortality did not increase with formaldehyde exposure levels. This observation led the researchers to conclude that factors other than formaldehyde exposure may have contributed to the increase in deaths. The latest lung cancer data from cohort studies have not found any relationship between formaldehyde exposure and lung cancer mortality.