Formaldehyde Exposure and Cancer Risk
Overview
Researchers in the Occupational and Environmental Epidemiology Branch (OEEB) have been conducting studies of occupational formaldehyde exposure and cancer risk since the 1980s. Early studies focused on surveys of professionals who are potentially exposed to formaldehyde in their work, such as anatomists and embalmers (Walrath and Fraumeni, 1983; Walrath and Fraumeni, 1984; Stroup et al., 1986; Hayes et al., 1990). Although these studies found that professionals were at increased risk for leukemia compared to the general population, they did not evaluate specific exposures or work practices.
Research Studies
Funeral Industry Workers
OEEB scientists investigated the relationship between work practices and formaldehyde exposure with risk for selected malignancies among workers in the funeral industry. Occupational histories were obtained from next of kin and co-workers for cases of lymphohematopoietic malignancies and for a control group of deaths due to other causes. Risk of death from myeloid but not other types of leukemia, was increased among those whose peak exposure to formaldehyde was highest. There was also evidence that greater than average levels of exposure to formaldehyde in these jobs was related to risk of death from myeloid leukemia (Hauptmann et al., 2009).
Formaldehyde Industrial Cohort
In the NCI Formaldehyde Industrial Cohort, which began in the 1980s and included 25,619 workers in industries with potential formaldehyde exposure, OEEB scientists estimated exposure based on work histories and plant-specific measurement data.
They found a possible link between formaldehyde exposure and lymphohematopoietic malignancies, particularly myeloid leukemia with peak exposure. When cumulative risk was evaluated, risks declined steadily over time, such that the cumulative excess risk of myeloid leukemia was no longer statistically significant at the end of the follow-up period. Similar to patterns of risk over time seen for known leukemogens, the risk for myeloid leukemia appeared to be highest earlier in the follow-up period. By the end of the follow-up period, the risk was no longer statistically significant (Beane Freeman et al., 2009).
Formaldehyde exposure was also associated with increased risk of death from nasopharyngeal cancer, a rare malignancy. No association with lung cancer was observed (Beane Freeman et al., 2013).
For more information, contact Dr. Laura Beane-Freeman.
Molecular Epidemiology Study of Formaldehyde
In the first chromosome-wide association study (CWAS) using cultured myeloid progenitor cells from workers exposed to formaldehyde, there was an increase in monosomy and trisomy of multiple chromosomes and an increase in structural chromosomal aberrations of chromosome 5 (Lan et al., 2015), which are often present in acute myeloid leukemia. Formaldehyde exposure was also associated with a decrease in levels of CD8+ effector memory T cells and regulatory T cells (Hosgood et al., 2013).
Results from these studies have been cited in several reviews on the carcinogenicity of formaldehyde, including those conducted by the International Agency for Research on Cancer and the National Toxicology Program (NTP) Report on Carcinogens (RoC) Outside Expert Panel.
For more information, contact Dr. Qing Lan.
Occupational and Environmental Epidemiology Branch - Research Areas
Public Health Impact of Formaldehyde Research
In 2014, an independent panel of scientists from the National Academy of Sciences (NAS) produced a report on formaldehyde carcinogenicity that affirmed the National Toxicology Program (NTP) 2011 classification in the 12th Report on Carcinogens (RoC).
They concluded there was “clear and convincing epidemiologic evidence to support the association of formaldehyde and nasopharyngeal cancer, sinonasal cancer, and myeloid leukemia in humans.” Panel members judged the strength of the evidence based on epidemiologic study design and exposure assessment methods.
Several DCEG studies were cited in the reviews, reflecting the Division’s seminal research among populations exposed to formaldehyde, particularly studies of workers with occupational exposure, led by OEEB investigators.
The NAS report was generated in response to a 2012 Congressional mandate for a review of the NTP’s evaluation and a separate comprehensive assessment of the peer-reviewed scientific literature. The panel took into consideration all relevant studies and reviews of formaldehyde, including human, animal, and mechanistic studies published.