Serum concentrations of selenium, selenium species and metals in children newly diagnosed with leukemia: a hospital-based case-control study

Exposure to metalloids and metals has been associated with childhood cancer, specifically acute leukemia, though studies are limited. During 2020-2023, we conducted a hospital-based case-control study in Italy to evaluate the association between trace element status and childhood leukemia. We enrolled 77 cases with newly-diagnosed acute childhood leukemia and 74 controls referred to the hospital for minor medical procedures. In blood samples collected at hospital admission, we used inductively-coupled plasma mass spectrometry to measure serum concentrations of selenium (and its species), copper, iron, manganese, and cadmium. We estimated odds ratios and 95% confidence intervals using restricted cubic spline regression. Dose-response, confounder-adjusted analyses showed positive monotonic associations of selenium, copper and iron, above a certain level of exposure, with childhood leukemia. Two selenium species, selenoprotein P-bound selenium and selenomethionine, showed similar results to total selenium. Zinc showed an inverse association with leukemia, while there was no appreciable relation with manganese. Copper concentrations in the top tertile were associated with the highest odds ratio of leukemia, though the association was imprecise. These findings indicate the need for further investigation of the potential adverse role of some selenium species and copper in childhood leukemia. However, reverse causation bias and residual confounding could not be ruled out as possible explanations for our findings.