Risk of Cancer in Children of Parents Occupationally Exposed to Hydrocarbon Solvents and Engine Exhaust Fumes: A Register-Based Nested Case–Control Study from Sweden (1960–2015)

BACKGROUND: It remains unclear whether parental occupational exposure to hydrocarbon solvents (HCS) or engine exhaust fumes (EEF) is associated with higher risks of cancer in the offspring. OBJECTIVES: Our aim was to estimate relative risks of childhood cancers associated with maternal or paternal exposure to aliphatic/alicyclic, aromatic, or chlorinated HCS or gasoline/diesel EEF. METHODS: We conducted a case–control study in which individuals [Formula: see text] old, born 1960–2014, were identified from the Swedish National Cancer Register (1960–2015) at first cancer diagnosis and matched to population controls (1 case:25 controls) on birth year and sex. Maternal and paternal occupation around the child’s birth was retrieved for 9,653 cases and 172,194 controls and 12,521 cases and 274,434 controls, respectively, using information from six censuses and a nationwide register. Using the Swedish job-exposure matrix (SWEJEM), we assessed exposure to HCS and EEF (any or higher/lower). Odds ratios (ORs) and 95% confidence intervals (CIs) of 15 childhood cancer subtypes were estimated using conditional logistic regression models adjusted for several confounders. RESULTS: Maternal exposure to aromatic HCS was associated with non-Hodgkin lymphoma ([Formula: see text]; 95% CI: 1.05, 2.58), aliphatic/alicyclic HCS with germ cell tumors ([Formula: see text]; 95% CI: 0.89, 2.59), and gasoline/diesel EEF with astrocytoma ([Formula: see text]; 95% CI: 1.04, 1.88), myeloid leukemia ([Formula: see text]; 95% CI: 0.84, 2.81), lymphomas ([Formula: see text]; 95% CI: 0.85, 3.02 for Hodgkin; [Formula: see text]; 95% CI: 0.71, 2.91 for non-Hodgkin), and epithelial tumors ([Formula: see text]; 95% CI: 0.93, 2.44). Paternal exposure to gasoline EEF was associated with Hodgkin lymphoma ([Formula: see text]; 95% CI: 1.01, 1.44) and soft tissue sarcomas ([Formula: see text]; 95% CI: 1.00, 1.48). No notable difference was observed between higher and lower exposure. DISCUSSION: Our findings suggest that occupational exposure to HCS or EEF, especially in the mother, may increase the risk of some childhood cancers. They add to the growing literature on adverse effects from HCS and EEF in the child, but replication of these associations in other populations is warranted. https://doi.org/10.1289/EHP11035