Investigating Childhood Leukemia in Churchill County, Nevada

Abstract

BackgroundSixteen children diagnosed with acute leukemia between 1997 and 2002 lived in Churchill County, Nevada, at the time of or before their illness. Considering the county population and statewide cancer rate, fewer than two cases would be expected.ObjectivesIn March 2001, the Centers for Disease Control and Prevention led federal, state, and local agencies in a cross-sectional, case-comparison study to determine if ongoing environmental exposures posed a health risk to residents and to compare levels of contaminants in environmental and biologic samples collected from participating families.MethodsSurveys with more than 500 variables were administered to 205 people in 69 families. Blood, urine, and cheek cell samples were collected and analyzed for 139 chemicals, eight viral markers, and several genetic polymorphisms. Air, water, soil, and dust samples were collected from almost 80 homes to measure more than 200 chemicals.ResultsThe scope of this cancer cluster investigation exceeded any previous study of pediatric leukemia. Nonetheless, no exposure consistent with leukemia risk was identified. Overall, tungsten and arsenic levels in urine and water samples were significantly higher than national comparison values; however, levels were similar among case and comparison groups.ConclusionsAlthough the cases in this cancer cluster may in fact have a common etiology, their small number and the length of time between diagnosis and our exposure assessment lessen the ability to find an association between leukemia and environmental exposures. Given the limitations of individual cancer cluster investigations, it may prove more efficient to pool laboratory and questionnaire data from similar leukemia clusters.

Levels of urinary total and speciated arsenic in the US population: National Health and Nutrition Examination Survey 2003–2004

“…In the German Environmental Survey III of 1998, median urinary total arsenic levels in 4052 adults varied with seafood intake and were approximately two-fold lower than those for NHANES 2003(Schulz et al, 2007. Higher mean or median (Calderon et al, 1999;Meza et al, 2004;Valenzuela et al, 2005;Josyula et al, 2006;Rubin et al, 2007), as well as for other areas of the world (Ahsan et al, 2000;Aposhian et al, 2000;Caceres et al, 2005;Sun et al, 2007), that were known to have higher levels of arsenic in their drinking water. Median and mean total urinary arsenic levels for residents in some districts in Bangladesh have been reported to be about 50-fold higher than the respective levels in NHANES 2003(Ahsan et al, 2000Chowdhury et al, 2003) and geometric mean levels were about 70-fold higher for residents of Inner Mongolia, China (Sun et al, 2007).…”

Action of the chemical agent fipronil (active ingredient of acaricide Frontline®) on the liver of mice: An ultrastructural analysis

“…In this sense, studies have been carried out to evaluate both toxic and carcinogenic effects of these products (Flores et al, 2004;Rubin et al, 2007;Shafer et al, 2005).…”

Fipronil (active ingredient of acaricide frontline®) acting on the mice thyroid

“…However, the indiscriminate practice has caused environmental impacts on the soil and water in a drastic way, which is sometimes difficult to measure. In this sense, some studies have demonstrated the toxic and carcinogenic effects of the plaguecides, especially those used in agriculture, which would contain organochlorate and pyrethroids, today forbidden in most developed countries, as well as in those in development (Flores et al, 2004;Rubin et al, 2007;Shafer et al, 2005). Currently, the so-called second-generation insecticides have proved to be more efficient and less toxic (Tingle et al, 2003).…”