Probability Estimates for the Unique Childhood Leukemia Cluster in Fallon, Nevada, and Risks Near Other U.S. Military Aviation Facilities Craig Steinmaus,1,2 Meng Lu,1 Randall L. Todd,3 and Allan H. Smith1 1Arsenic Health Effects Research Group, School of Public Health, University of California, Berkeley, California, USA; 2Division of Occupational and Environmental Medicine, University of California, San Francisco, California, USA; 3Nevada State Health Division, Carson City, Nevada, USA Abstract A unique cluster of childhood leukemia has recently occurred around the city of Fallon in Churchill County, Nevada. From 1999 to 2001, 11 cases were diagnosed in this county of 23,982 people. Exposures related to a nearby naval air station such as jet fuel or an infectious agent carried by naval aviators have been hypothesized as potential causes. The possibility that the cluster could be attributed to chance was also considered. We used data from the Surveillance, Epidemiology, and End Results Program (SEER) to examine the likelihood that chance could explain this cluster. We also used SEER and California Cancer Registry data to evaluate rates of childhood leukemia in other U.S. counties with military aviation facilities. The age-standardized rate ratio (RR) in Churchill County was 12.0 [95% confidence interval (CI) , 6.0-21.4 ; p = 4.3 10-9]. A cluster of this magnitude would be expected to occur in the United States by chance about once every 22,000 years. The age-standardized RR for the five cases diagnosed after the cluster was first reported was 11.2 (95% CI, 3.6-26.3) . In contrast, the incidence rate was not increased in all other U.S. counties with military aviation bases (RR = 1.04 ; 95% CI, 0.97-1.12) or in the subset of rural counties with military aviation bases (RR = 0.72 ; 95% CI, 0.48-1.08) . These findings suggest that the Churchill County cluster was unlikely due to chance, but no general increase in childhood leukemia was found in other U.S. counties with military aviation bases. Key words: ALL, childhood cancer, cluster, leukemia, military. Environ Health Perspect 112:766-771 (2004) . doi:10.1289/ehp.6592 available via http://dx.doi.org/ [Online 2 February 2004] Address correspondence to C. Steinmaus, School of Public Health, 140 Warren Hall, University of California, Berkeley, CA 94760-7360 USA. Telephone: (510) 504-5395. Fax: (510) 843-5539. E-mail: craigs@uclink.berkeley.edu Work reported here was supported in part by grant 1 K23 ESO11133-01 from the National Institute of Environmental Health Sciences (NIEHS) and the University of California Center for Occupational and Environmental Health. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS. The authors declare they have no competing financial interests. Received 14 July 2003 ; accepted 2 February 2004. The full version of this article is available for free in HTML or PDF formats. |