Laura Beane Freeman, Ph.D.
|Organization:||National Cancer InstituteDivision of Cancer Epidemiology & Genetics, Occupational and Environmental Epidemiology Branch|
|Address:||NCI Shady GroveRoom 6E610|
Dr. Beane Freeman completed her doctorate in epidemiology at the University of Iowa in 2003. She then joined the Cancer Prevention Fellowship Program and conducted her postdoctoral training within the Occupational and Environmental Epidemiology Branch (OEEB). She was appointed to the tenure track in 2009.
The focus of Dr. Beane Freeman’s work includes a number of occupational and environmental exposures. Specifically, she conducts research related to agriculture, including pesticides; drinking water contaminants, such as disinfection by-products; and industrial chemical exposures such as formaldehyde.
Studies around the world have observed that farmers and other agricultural workers are at elevated risk of several specific cancers, despite lower overall mortality and, in particular, cancer mortality. In this occupational group, excess risks are observed for Hodgkin lymphoma, non-Hodgkin lymphoma, leukemia, multiple myeloma, and cancers of the brain, skin, lip, stomach, and prostate. Work-related exposures suspected of contributing to the excesses include pesticides, viruses, mycotoxins, well-water contaminants, and a variety of other agents encountered in the agricultural environment.
The Agricultural Health Study is a collaboration of the NCI, the National Institute of Environmental Health Sciences, the National Institute for Occupational Safety and Health, and the Environmental Protection Agency. This prospective cohort study of approximately 90,000 participants includes licensed private pesticide applicators and their spouses in Iowa and North Carolina, and commercial applicators in Iowa. The purpose is to evaluate agricultural exposures that may be related to cancer and other health outcomes. Several associations have been observed between specific pesticides and cancer sites in the pesticide applicators. For example, diazinon has been associated lung cancer, leukemia and follicular lymphoma in the cohort, and was recently listed as a Group 2A, probable human carcinogen by the International Agency for Research on Cancer (IARC). We have also recently reported a novel association between metolachlor, an herbicide, and liver cancer, which mimics associations seen in animal studies. Although many evaluations have been conducted in pesticide applicators, we are now taking advantage of the information available for the spouses of the pesticide applicators to investigate associations between pesticide exposure through multiple pathways (occupational and environmental) and cancer risks among these women.
In addition to pesticides, we are investigating other exposures within the agricultural environment such as exposure to livestock and poultry, diesel exhaust and endotoxins and other bioaerosols. We are actively collaborating with investigators from other agricultural cohort studies involved in AGRICOH, a consortium of agricultural cohorts, to replicate and extend a number of our findings in the AHS.
My research in this area has been to (1) assess whether occupational exposure to formaldehyde increases the risk of cancer at a number of sites, specifically the respiratory tract and lymphohematopoietic malignancies, and (2) evaluate the biologic plausibility of formaldehyde carcinogenicity, particularly at sites distant from the respiratory tract. The NCI Cohort of Workers in Formaldehyde Industries is the largest study of occupationally exposed workers and includes over 25,000 participants who have a median follow-up time of over 40 years. Our most recent follow-up on this study added another 10 years of mortality data, allowing us sufficient person years to explore effects at different time periods and offered further insight into temporality of potential associations between formaldehyde and leukemia and other lymphohematopoietic malignancies.
Results from previous studies indicate that exposure to disinfection by-products (DBPs) increases risk of bladder cancer. However, as DBPs are a complex mixture of chemicals, questions remain about the etiologic agents responsible for the associations. Recent results from a case-control study in Spain suggest that in addition to ingestion, exposure through showering and bathing may contribute to risk. Using detailed exposure assessment methods, we have conducted etiologic analyses of DBPs to investigate whether these results can be replicated within a large case-control study within the United States.