233319 Risk of non-Hodgkin lymphoma and drinking water contaminants in Nebraska: Atrazine and nitrate

Wednesday, November 10, 2010 : 8:30 AM - 8:50 AM

Martha Rhoades, PhD , Department of Environmental, Agricultural and Occupational Health and School of Natural Resources, University of Nebraska Medical Center and University of Nebraska-Lincoln, Lincoln, NE
Jane Meza, PhD , Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE
Cheryl Beseler, PhD , formerly Department of Epidemiology, University of Nebraska Medical Center, Omaha, NE
Julie Vose, MD , Division of Hematology/Oncology, University of Nebraska Medical Center, Omaha, NE
Patrick Shea, PhD , Department of Environmental, Agricultural and Occupational Health and School of Natural Resources, University of Nebraska Medical Center and University of Nebraska-Lincoln, Lincoln, NE
Roy Spalding, PhD , Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE
     
The increased incidence of non-Hodgkin lymphoma (NHL) in the midwestern United States has been associated with agricultural practices. Recurring themes are nitrate-contaminated drinking water and pesticide exposures. Some reports suggest cancer risk associated with consumption of nitrate-contaminated drinking water is due to endogenous nitrosamine formation. Groundwater provides drinking water to over 80% of Nebraska residents. Atrazine, a herbicide heavily used in agriculture for more than 40 years, is a nitrosatable compound that has been detected in groundwater. The objective of this study was to determine the risk of NHL due to exposure to drinking water contaminated with nitrate or atrazine alone or in combination. A subset of 140 cases and 192 controls from a case control study conducted during 1999-2002 were included. Water data from 1978-1998 was collected from 98 public water systems and weighted based on well contribution and proximity of residence to water supply. No association was found between risk of NHL and nitrate or atrazine alone in drinking water. After adjusting for confounders, increased risk of NHL was associated with drinking water contaminated with both atrazine and nitrate (OR=2.5; 95% confidence interval (CI): 1.0-6.2). After adjusting for confounders, the risk of indolent B-cell lymphoma was significantly greater (OR=3.5; 95% CI: 1.0-11.6) for those exposed to nitrate and atrazine contaminated drinking water than those not exposed. It is hypothesized that this increased risk of NHL may be due to endogenous formation of N-nitrosoatrazine after drinking water contaminated with atrazine and nitrate. Further investigation is warranted to verify this association.

Learning Areas:
Environmental health sciences
Epidemiology

Learning Objectives:
Explain the biological plausibility of increased risk of NHL due to N-nitrosoatrazine formation after exposure to atrazine and nitrate in drinking water. Discuss the importance of drinking water infrastructure when assessing exposure to drinking water contaminants using historical water data. Explain how agricultural management practices can be utilized to determine bias associated with estimating exposure when water quality data are missing.

Keywords: Cancer, Water Quality

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I gathered, transcribed and analyzed the water quality data and performed the final analysis for this epidemiology project.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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