Abstract
BackgroundTraffic exhaust, refineries and industrial facilities are major sources of air toxics identified by the U.S. Environmental Protection Agency (U.S. EPA) for their potential risk to human health. In utero and early life exposures to air toxics such as benzene and 1,3-butadiene, which are known leukemogens in adults, may play an etiologic role in childhood leukemia that comprises the majority of pediatric cancers. We conducted a population based case–control study to examine individual effects of benzene, 1,3-butadiene and polycyclic organic matter (POM) in ambient residential air on acute lymphocytic leukemia (ALL) diagnosed in children under age 5 years in Texas from 1995–2011.MethodsTexas Cancer Registry cases were linked to birth records and then were frequency matched by birth month and year to 10 population-based controls. Maternal and infant characteristics from birth certificates were abstracted to obtain information about potential confounders. Modelled estimates of benzene, 1,3-butadiene and POM exposures at the census tract level were assigned by linking geocoded maternal addresses from birth certificates to U.S. EPA National-Scale Air Toxics Assessment data for single and co-pollutant statistical analyses. Mixed-effects logistic regression models were applied to evaluate associations between air toxics and childhood leukemia.ResultsIn adjusted single pollutant models, odds of childhood leukemia among mothers with the highest ambient air exposures compared to those in the lowest quartile were 1.11 (95 % CI: 0.94–1.32) for POM, 1.17 (95 % CI: 0.98–1.39) for benzene and 1.29 (95 % CI: 1.08–1.52) for 1,3-butadiene. In co-pollutant models, odds ratios for childhood leukemia remained elevated for 1,3-butadiene but were close to the null value for benzene and POM.ConclusionsWe observed positive associations between 1,3-butadiene and childhood leukemia in single and co-pollutant models whereas effect estimates from single pollutant models were diminished for benzene and POM in co-pollutant models. Early life exposure to 1,3-butadiene rather than benzene or POM appears to increase early childhood risk of acute lymphocytic leukemia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0154-8) contains supplementary material, which is available to authorized users.
Highlights
Traffic exhaust, refineries and industrial facilities are major sources of air toxics identified by the U.S Environmental Protection Agency (U.S EPA) for their potential risk to human health
We evaluated associations between residential exposures to air toxics, namely, benzene, 1,3-butadiene and polycyclic organic matter (POM), and acute lymphocytic leukemia (ALL) in children diagnosed under age 5 years in Texas from 1995 to 2011
This study is among relatively few investigations that have examined risk of ALL relative to ambient exposures to benzene, 1,3-butadiene and POM among children less than 5 years
Summary
Refineries and industrial facilities are major sources of air toxics identified by the U.S Environmental Protection Agency (U.S EPA) for their potential risk to human health. In utero and early life exposures to air toxics such as benzene and 1,3-butadiene, which are known leukemogens in adults, may play an etiologic role in childhood leukemia that comprises the majority of pediatric cancers. We conducted a population based case–control study to examine individual effects of benzene, 1,3-butadiene and polycyclic organic matter (POM) in ambient residential air on acute lymphocytic leukemia (ALL) diagnosed in children under age 5 years in Texas from 1995–2011. About 80 % of childhood leukemias are acute lymphocytic leukemia (ALL) with approximately 2,200 new cases of ALL diagnosed annually in children under 15 years in the United States [2]. We focused on polycyclic organic matter (POM) representing a broad range of organic compounds comprised of two to seven fused aromatic rings of which polycyclic aromatic hydrocarbons (PAHs) are the most common subclass [18, 19]
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