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Investigating childhood leukemia in Churchill County, Nevada
Carol S Rubin1, Adrianne K Holmes, Martin G Belson
1National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA. crubin@cdc.gov
Environmental Health Perspectives
|March 21, 2007
Summary
A leukemia cluster in Nevada showed no definitive environmental cause. Higher tungsten and arsenic levels were found, but not linked to illness, suggesting pooled data may be more effective for future studies.
Area of Science:
- Environmental epidemiology
- Pediatric oncology
- Toxicology
Background:
- An unusual number of pediatric leukemia cases (16) were identified in Churchill County, Nevada, between 1997-2002.
- This incidence significantly exceeded the expected rate based on county population and state cancer statistics.
Purpose of the Study:
- To investigate potential environmental exposures linked to a pediatric leukemia cluster in Churchill County, Nevada.
- To compare environmental and biological contaminant levels between affected families and a control group.
Main Methods:
- A cross-sectional, case-comparison study involving surveys administered to 205 individuals in 69 families.
- Analysis of biological samples (blood, urine, cheek cells) for 139 chemicals, viral markers, and genetic polymorphisms.
- Measurement of over 200 chemicals in environmental samples (air, water, soil, dust) from nearly 80 homes.
Main Results:
- No specific environmental exposure strongly associated with leukemia risk was identified despite the extensive investigation.
- Elevated levels of tungsten and arsenic were detected in urine and water samples compared to national averages.
- These higher contaminant levels were present in both case and comparison groups, indicating no clear link to the leukemia cluster.
Conclusions:
- The small number of leukemia cases and the time lag between diagnosis and exposure assessment limited the ability to establish a definitive environmental link.
- Individual cancer cluster investigations may be insufficient; pooling data from similar leukemia clusters could offer greater efficiency and statistical power.
