180385 Leukemia incidence and benzene air pollution in Portland Oregon: An ecologic investigation

Monday, October 27, 2008

Robert W. Voss, MS , Public Health (Environmental Health) (alum), Oregon State University, Marina, CA
Anna Harding, PhD , Department of Public Health, Oregon State University, Corvallis, OR
William E. Lambert, PhD , Public Health and Preventive Medicine, Oregon Health Sciences University, Portland, OR
Benzene is a widespread urban pollutant emitted by industrial sources and transportation vehicles. Nationally and in Oregon, benzene is the largest contributor to total cancer risk from air pollutants. This study sought to determine if the incidence of acute myeloid leukemia in Portland, Oregon during the period 1995-2004, varied with ambient airborne benzene. We used modeled ambient benzene exposure and leukemia incidence data at the census tract level to examine the correlation of benzene with three leukemia types. Modeled benzene values were averaged to census tracts using GIS methods. We performed Poisson regression on data for all census tracts and also aggregated data to quartiles of benzene modeled exposure to determine incidence rate ratios (IRR). We mapped the distribution of benzene, and age-standardized leukemia rates to examine spatial distribution patterns. Results showed no overall statistically significant association between benzene and leukemia at the census tract level. Acute myeloid leukemia (AML) was slightly elevated for females at the second quartile of benzene modeled exposure. We did not observe an increasing trend of higher cancer incidence with higher modeled benzene exposure; however, we did see increased cancer incidence near some point sources for adult AML and near roads for total myeloid leukemia in those under age 19. Proximity to traffic may be a better approximation of exposure risk for leukemia than modeled benzene exposure at the census tract level. Available census tract level data may not represent mobile source pollution accurately enough to always be useful in ecologic studies of leukemia.

Learning Objectives:
1) Define Hazardous Air Pollutants (HAPs), their sources, health risks and available data sets describing their distribution. 2) Assess the strengths and weaknesses of an ecologic study design using group level data to assess the health impacts of widespread ambient air pollutants. 3) Articulate the magnitude of cancer incidence predicted by U.S. EPA risk assessment methodology for ambient airborne benzene pollution.

Keywords: Environmental Exposures, Air Pollutants

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: Abstract represents masters thesis of primary author (self).
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.