Prolonged exposure to formaldehyde linked with increased risk of myeloid leukemia

Long durations of exposure to formaldehyde used for embalming in the funeral industry were associated with an increased risk of death from myeloid leukemia, according to a new study published online November 20 in the Journal of the National Cancer Institute.

Previous studies have shown excess mortality from lymphohematopoietic malignancies and brain cancer in anatomists, pathologists, and funeral industry workers, all of whom may have worked with formaldehyde.

For this study, researchers at the Division of Cancer Epidemiology and Genetics at the National Cancer Institute in Bethesda, Md., and colleagues investigated the relation of mortality to work practices and formaldehyde exposure levels among these professionals. In a case-control study among funeral industry workers who had died between 1960 and 1986, researchers compared those who died from lymphohematopoietic malignancies and brain tumors with those who died from other causes. Lifetime work practices and exposures to formaldehyde were obtained by interviews with next of kin and coworkers.

This study was the first epidemiological investigation, to the authors' knowledge, to relate cancer risk to duration of employment, work practices, and estimated formaldehyde exposure levels in the funeral industry.

The number of years of embalming practice and related formaldehyde exposures were associated with statistically significantly increased mortality from myeloid leukaemia, with the greatest risk among those who practiced embalming for more than 20 years. No associations were observed with other lymphohematopoietic malignancies; associations with brain cancer were unclear.

"This study adds supporting and complementary data to other epidemiological evidence of an association between formaldehyde exposure and risk of myeloid leukemia," the authors write. "Further studies of leukemia risk in relation to specific embalming practices and exposures, as well as similar specific exposure studies in other professional groups that are exposed to formaldehyde and that have an increased risk of leukaemia, should help to clarify our understanding of cancer risks related to formaldehyde."