Maternal exposure to heavy metals from industrial sources during pregnancy and childhood cancer risk in California

Objective The study investigated maternal exposure to heavy metals from industrial sources during pregnancy as potential risk factors for childhood cancer. Methods Cases ages 0–19 were identified from California Cancer Registry. Controls (20:1 ratio) were randomly selected from California Birth Registry, frequency-matched by birth year (1998–2016). We estimated maternal exposure to lead, nickel, and cobalt in ambient air from the Toxics Release Inventory. We examined “ever/never” and “high/low” exposures categorized by median exposure. Models were adjusted for maternal age, race/ethnicity, method of payment for prenatal care, neighborhood socioeconomic status, and urban/rural residence. Results Among highly exposed persons, lead was associated with an increased teratoma risk (adjusted odds ratio [aOR]: 1.52; 95% confidence interval [CI]: 0.97, 2.37), whereas nickel was associated with an increased rhabdomyosarcoma risk (aOR: 1.45; 95% CI: 1.03, 2.04). Cobalt was associated with an increased glioma risk (aOR: 2.25; 95% CI: 1.39, 3.65) among ever-exposed persons. Inverse associations were found between Wilms tumor and nickel among the ever exposed and highly exposed (ever: aOR: 0.75; 95% CI: 0.59, 0.96; high: aOR: 0.64; 95% CI: 0.45, 0.93). Conclusions Findings suggest that air pollution from heavy metals released by industrial sources may elevate childhood cancer risk.