Benzene and childhood acute leukemia in Oklahoma

Abstract

Background Although childhood cancer is a leading cause of childhood mortality in the US, evidence regarding the etiology is lacking. The goal of this study was to evaluate the association between benzene, a known carcinogen, and childhood acute leukemia. Methods We conducted a case-control study including cases diagnosed with acute leukemia between 1997 and 2012 (n=307) from the Oklahoma Central Cancer Registry and controls matched on week of birth from birth certificates (n=1,013). We used conditional logistic regression to evaluate the association between benzene, measured with the 2005 National-Scale Air Toxics Assessment (NATA) at census tract of the birth residence, and childhood acute leukemia. Results We observed no differences in benzene exposure overall between cases and controls. However, when stratified by year of birth, cases born from 2005-2010 had a three–fold increased unadjusted odds of elevated exposure compared to controls born in this same time period (4th Quartile OR: 3.53, 95% CI: 1.35, 9.27). Furthermore, the estimates for children with acute myeloid leukemia (AML) were stronger than those with acute lymphoid leukemia, though not statistically significant. Conclusions While we did not observe an association between benzene and childhood leukemia overall, our results suggest that acute leukemia is associated with increased benzene exposure among more recent births, and children with AML may have increased benzene exposure at birth. Using the NATA estimates allowed us to assess a specific pollutant at the census tract level, providing an advantage over monitor or point source data. Our study, however, cannot rule out the possibility that benzene may be a marker of other traffic-related exposures and temporal misclassification may explain the lack of an association among earlier births.

Association between Outdoor Air Pollution and Childhood Leukemia: A Systematic Review and Dose–Response Meta-Analysis

“…Dose–response meta-analysis of childhood leukemia risk from benzene exposure for (A) all leukemias (Crosignani et al 2004; Heck et al 2014; Houot et al 2015; Janitz et al 2017; Raaschou-Nielsen et al 2018; Vinceti et al 2012), (B) acute lymphoblastic leukemia only (Crosignani et al 2004; Heck et al 2014; Houot et al 2015; Janitz et al 2017; Raaschou-Nielsen et al 2018; Vinceti et al 2012), and (C) acute myeloid leukemia only (Heck et al 2014; Houot et al 2015; Janitz et al 2017; Raaschou-Nielsen et al 2018; Vinceti et al 2012). Spline curve (black solid line) with 95% confidence limits (gray dashed lines).…”

Air Pollution and Noncommunicable Diseases

“…22 Benzene exposure from vehicular exhaust, especially during the prenatal period and in the early years of childhood, has been associated with the risk of childhood leukemia. 23 Prenatal exposure to PM 2.5 during pregnancy may increase a child's risk of developing leukemia and astrocytomas. 24…”

Epidemiology and Etiology of Leukemia and Lymphoma

“…Pediatric leukemia is also associated with certain therapeutic exposures, such as chemotherapy with alkylating agents and topoisomerase II inhibitors for primary cancers (Hijiya et al 2009); diagnostic exposures such as ionizing radiation from CT scans (Pearce et al 2012); and organ transplantation, which may be related to iatrogenic immunosuppression and exposure to oncogenic viruses (Yanik et al 2017). Several recent studies indicate that environmental exposure to benzene (e.g., via proximity to automobile traffic and factories), elevates AML risk in children (Honoré et al 2015;Janitz et al 2017).…”