The association of urinary levels of heavy metals with childhood acute leukemia and its socio-environmental risk factors: A case-control study.

Childhood acute leukemia is the most common type of cancer in children worldwide, accounting for 30% of all childhood cancers. This study aimed to evaluate the possible association between urinary heavy metals (HMs) concentration and the risk of childhood acute lymphoblastic leukemia (C-ALL) in children. The effects of socio-environmental factors also were investigated. In this case-control study, urinary concentrations of selected HMS were determined in urine samples of 124 children with acute leukemia (cases) and 104 healthy controls using ICP-OES. The social, economic, and environmental characteristics of participants were collected by a questionnaire. Multifactorial logistic regression models were applied to investigate the associations after adjustments for confounding factors. The creatinine-adjusted urinary concentrations of arsenic, cadmium, and lead in cases were significantly higher than healthy controls (the concentrations of nickel, chromium, and selenium were not significantly different). Multifactorial logistic regression in different adjusted models showed that the higher urinary concentrations of arsenic, lead, and cadmium increased the risk of C-ALL up to 2.5, 2.73, and 2.37 times, respectively. Urinary levels of Cd also showed a significant correlation with the risk of ALL. Among the socio-environmental risk factors, living near roads with heavy traffic, distance of living location from industrial zones, parental smoking, and consumption of rice as a staple food significantly increased the risk of C-ALL. This study suggested a strong association between arsenic, cadmium, and lead with acute leukemia in children. Further studies are necessary to clarify the role of these metals in the pathogenesis of different types of leukemia.