Individual and mixed urinary trace metal exposures and their associations with prostate cancer in Tanzania: A case-control study using BKMR.

Trace metals are essential for normal physiology, but their imbalance may contribute to cancer. In Tanzania, evidence linking trace metal exposure to prostate cancer remains inconsistent, particularly for combined exposures. This study investigated associations between urinary trace metals and prostate cancer using logistic regression and Bayesian Kernel Machine Regression (BKMR). A total of 180 participants, comprising 100 prostate cancer patients and 80 controls, were enrolled. Urine samples were digested using nitric acid and hydrogen peroxide, and trace metals were determined by inductively coupled plasma atomic emission spectrometry. Cancer patients had significantly higher concentrations of Co, Se, Cu, and Mn, whereas Zn, Cr, and Fe were higher among controls. Logistic regression showed that Cu was significantly associated with prostate cancer while Se demonstrated an inverse association with prostate cancer. BKMR indicated no significant association between metal mixture and prostate cancer. Overall, Cu may increase risk, while Se was inversely associated with prostate cancer. Prospective studies are needed to validate findings and clarify combined metal effects.