Churchill County Leukemia Cluster
Between 1999 and 2001, sixteen cases of acute lymphocytic leukemia (ALL) were diagnosed in children who either were or had been residents in rural Churchill County, Nevada at the time of diagnosis.
The number of cases was considered to be highly unusual and unlikely, based on the number of residents in the county (approximately 24,000) and the short period in which the cases were diagnosed. The cases were characterized as a cluster of like illnesses and the probability of having such a cluster occur by chance alone was estimated to be very small (p=4.3´10-9). This suggested that the cluster could be linked to external chemical or biological causes. Hypotheses that arose and were tested focused on potential exposure to cancer-causing agents in the environment, including airborne and water-borne contaminants, and contaminants that could be uniquely associated with occupation of the parents in the homes with children diagnosed with ALL. In addition to potential links to environmental chemicals, an expert panel discussed a population mixing hypothesis, in part because of the large number of short-term visitors in the county associated with a military training facility. Subsequently, several epidemiological surveys and environmental investigations examined associations between chemicals present in the environment (both naturally occurring and anthropogenic), radioactive isotopes in water, chemicals used for agricultural production and within homes for pest control, and chemicals in air and airborne dust.
In 2007, with an allocation of funds from the U.S. Senate, researchers at the University of Nevada, Reno, the University of California at San Francisco and the University of Arizona focused on specific chemicals and aspects of leukemogenesis that were beyond the scope of the epidemiological studies carried out as initial responses to the cluster. The funds were released to a community group from Churchill County composed of members of the families with children diagnosed with ALL. The researchers selected to carry out individual projects included a multi-disciplinary team, with backgrounds in groundwater flow and contamination, leukemia, cell response to stresses, and unique approaches to assessing long-term exposure to potential contaminants. The information provided on this web site represents progress with these topics, with research that was in final stages in April 2010.
The results of this research, presented here in presentation form, will be the subject of a special issue of Chemico-Biological Interactions, planned for March 2011.
- No Answers, Possible Clues in Fallon Cancer Cluster, March 25, 2010, KoloTV.com
- Researchers to discuss 1997–2004 leukemia cluster data, March 18, 2010, UNR Nevada News
- Tree Rings Show Elevated Tungsten Coincides With Nevada Leukemia Cluster,May 5, 2007, Medical News Today
- Focus on FALLON: Cancer cluster confounds experts November 17, 2002, Las Vegas Review Journal
Awarded in August 2006; ending in June 2011
- Centers for Disease Control and Prevention
- Churchill County, Nevada: http://www.churchillcounty.org/
- State of Nevada, Department of Conservation and Natural Resources, Division of Environmental Protection, Churchill County, Nevada -- Leukemia Investigation