"We know that various groups of professionals who may experience high peak exposures to formaldehyde are at increased risk of leukemia, but the evidence from studies of industrial workers, among whom exposure levels and patterns may be more variable, has been conflicting. The fact that we see an excess in this study of industrial workers, which is both the largest and the one with the most extensive exposure assessment, is notable," said Beane Freeman.
Based on the available data, scientists have not been able to identify a mechanism for how normal white blood cells might become leukemic following exposure to formaldehyde, because there is no direct evidence that formaldehyde damages cells in the bone marrow. However, studies of humans exposed to inhaled formaldehyde have shown higher rates of damage to their chromosomes in a type of mature white blood cells compared with rates in individuals who were not exposed to formaldehyde. Although the relevance to the development of leukemia of such chromosomal damage to mature white blood cells is not clear, agents that cause leukemia are also known to be associated with chromosomal aberrations in the peripheral blood cells of humans.
This study is also the first to report a statistically significant association between a chemical exposure and increased risk of death from Hodgkin lymphoma. Although based on a small number of deaths, the finding may warrant further study.
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For a fact sheet on cancer risk due to formaldehyde exposure, please go to http://www.cancer.gov/cancertopics/factsheet/Risk/formaldehyde.
NCI leads the National Cancer Program and the NIH effort to dramatically reduce the burden of cancer and improve the lives of cancer patients and their families, through research into prevention and cancer biology, the development of new interventions, and the training and mentoring of new researchers. For more information about cancer, please visit the NCI Web site at http://www.cancer.gov or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).
For more information on Dr. Beane Freeman's research, please go to http://dceg.cancer.gov/about/staff-bios/beane-freeman-laura.
Reference: Beane Freeman LE, Blair A, Lubin JH, Stewart PA, Hayes RB, Hoover RN, and Hauptmann M. Mortality from Lymphohematopoietic Malignancies Among Workers in Formaldehyde Industries: The National Cancer Institute Cohort. May 20, 2009, JNCI, Vol. 101, No. 10.