Association between exposure to heavy metals and the risk of breast cancer: A case-control study in Tanzania

Exposure to heavy metals is suspected to influence breast cancer development, although epidemiological evidence regarding this association remains controversial. This study investigated the association between urinary heavy metal levels and breast cancer risk through a hospital-based case-control design, involving 50 breast cancer patients and 40 healthy females. Heavy metals were quantified using an inductively coupled plasma atomic emission spectrophotometer (ICP-AES). The exposure levels were categorized into quartiles, and logistic regression was employed to evaluate the breast cancer risk associated with heavy metal exposure. The results revealed positive associations between risk of breast cancer and concentrations of Al, As, Ni, Cd, and Pb. In addition, the risk of breast cancer was high among participants in the 2nd, 3rd, and 4th quartiles of Al, As, Ni, Cd, and Pb. However, Co showed an inverse association with breast cancer. These results indicate that increased concentrations of heavy metals, with the exception of Co, are associated with the risk of breast cancer. •Heavy metals were quantified in urine samples of both breast cancer and controls.•High levels of all studied metals were found in breast cancer compared to controls.•Al, As, Pb, and Ni were associated with increased odds of breast cancer.•Cobalt may be protective against breast cancer; found to be inversely associated.•Heavy metal exposure may be associated with high risk of breast.