Maternal occupational benzo(a)pyrene exposure and risk of cancer in children

Abstract

Background/Aim: The International Agency for Research on Cancer has classified benzo(a)pyrene (BaP) as carcinogenic to humans, based on sufficient evidence of carcinogenicity in experimental animals and supportive data on mechanistic pathways in humans. BaP is also a developmental toxicant. Yet, few studies assessed whether parental exposure to BaP is related to an increased risk for childhood cancers. Previous studies reported possible associations between environmental BaP exposure with risk increases in neuroblastoma and acute lymphoblastic leukemia. The aim of our study was to examine the relation between maternal occupational BaP exposure with risk of cancer in offspring.Methods: In this case-control study of Danish children (8339 cases, 208475 controls), we ascertained cases from the Cancer Registry and controls from the Central Population Register. Jobs during pregnancy were ascertained from the Supplemental Pension Fund, a mandatory supplement to the state pension. BaP exposure was determined via a job-exposure matrix developed for the Danish workforce. We used conditional logistic regression to determine associations with childhood cancer.Results: Ever occupational exposure to BaP during pregnancy was related to an increase in risk of neuroblastoma (Odds Ratio=1.65, 95% Confidence Interval 1.22, 2.23), while there was no increased risk for ALL (OR=1.02). We did not estimate any compelling risk increase for any other type of cancer, with effect estimates close to the null.Conclusions: This is the second study to report possible associations between BaP and neuroblastoma. Occupational exposures tend to be higher than ambient environmental exposures likely leading to greater fetal loss, which may in part explain variation in leukemia results compared to other studies.