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Determining whether the incidence of cancer may be associated with pollutants emitted from airports is important in order to better plan cities to reduce such incidences. This research aims to answer the following questions: 1) Is there a trend between the incidence of various kinds of cancer and proximity to air emission sources, including airports, in Texas? and 2) Specifically, is there a relationship between childhood leukemia and airport benzene emissions? Texas has two airports ranked among the top 10 U.S. airports in terms of enplanements for Jan.-March 2010: Houston ranked 7th, while Dallas was 3rd. 1 State-wide cancer incidence data was obtained in July of 20092; additionally, state-wide data on age, race and gender-specific cancer rates3,4,5,6 were obtained from the Texas Department of State Health Services (DSHS)7. These rates were applied to the demographic make-up of each geographical unit to compute the number of cancer cases which would be expected in each area. The observed number of cases in each area was compared to the expected number for leukemia, lymphoma (both for children 9 years and under), colon and respiratory (both for all ages) cancers at the state-wide block group level. Colon cancer was used as a negative control because benzene exposures are not expected to be associated with the incidence of colon cancer. The ratio of the number of observed cases was divided by the number of expected cases for each block group and was then plotted against the distance to major emission sources (railroads, airports, industrial facilities and roads), using Geographical Information Systems (GIS). In order to address the second question of a relationship between childhood leukemia and airport benzene emissions, a Poisson regression model was developed using county emissions as the predictor variables and childhood leukemia as the response variable. Additionally, distance to the emission sources for children under age 9 with and without leukemia was compared. The 3 analyses all suggest that airport benzene emissions contribute to incidences of childhood leukemia. |
