BACKGROUND: Due to concerns over the impact of traffic-related air pollution on childhood cancers, we evaluated the association between residential proximity to major roadways and childhood central nervous system (CNS) tumors.
METHODS: The Texas Cancer Registry provided information on children diagnosed with a CNS tumor at <5 years of age and born in Texas for the period 2003-2009 (n=315). Birth certificate controls were frequency matched to cases (5:1) on birth year (n=1575). We assigned exposures to traffic-related air pollution using residential proximity to major roadways based on the maternal residence at the time of delivery. Logistic regression was used to generate unadjusted and adjusted odds ratios and 95% confidence intervals (CI). We evaluated CNS tumors as a group and by histologic type.
RESULTS: Maternal residential proximity to major roadways at delivery was positively associated with the odds of offspring having a CNS tumor. Specifically, for every kilometer closer to a major roadway, the odds of offspring having a CNS tumor increased by 30% (95% CI: 1.0, 1.7). Mothers living ≤500 meters (m) from a major roadway were 31% (95% CI: 1.0, 1.8) more likely to have offspring with any CNS tumor and 3.1-times (95% CI: 0.9, 10.4) more likely to have offspring with an ependymoma compared to mothers living >500m from the nearest major roadway. Moreover, compared to mothers living in areas with low roadway density, those living in areas with high roadway density were 51% (95% CI: 1.1, 2.1) more likely to have offspring with any CNS tumor and 4.2-times (95% CI: 1.2, 14.9) more likely to have offspring with an ependymoma. There were no statistically significant associations observed between continuous distance to major roadways and ependymoma as well as between the proximity measures and the other evaluated CNS tumor phenotypic groups.
CONCLUSIONS: The results of this large population-based study indicate that mothers who live near major roadways or in areas with high roadway density may be more likely to have offspring with a CNS tumor, particularly an ependymoma.
