Association between single and mixed exposure to potentially toxic trace metals and the risk of prostate cancer: a case-control study in Tanzania.

Abstract

Metal contamination is a major environmental concern in Tanzania, where it has been linked to an increased risk of prostate cancer. However, there have been no epidemiological studies addressing this association. The aim of this study was to investigate the association between urinary toxic trace metals and prostate cancer. Inductively coupled plasma atomic emission spectrophotometer (ICP-AES) was employed to measure the concentrations of Pb, As, Ni, Al, and Cd in urine samples from histologically confirmed100 prostate cancer patients (n = 100) and 80 healthy controls (n = 80). The associations between individual metals and prostate cancer were assessed using unconditional logistic regression, while Bayesian kernel machine regression (BKMR) was employed to investigate the combined effects of multiple metals with adjustments of potential covariates. Cancer patients had significantly higher mean levels of Ni, Pb, and As in their urine compared to controls. In multivariable logistic models, the findings suggested that quartiles increase of As and Cd were positively associated with prostate cancer with ORs of 5.25 (1.33, 20.72) in Q3 for As and ORs of 2.87 (1.72, 11.52) in Q4 for Cd. The BKMR results revealed that the combined effect of five urinary metals exhibited a negative association with prostate cancer risk. In conclusion, this study offers preliminary evidence suggesting that exposure to trace metals particularly Cd and As may potentially be associated with prostate cancer. Pb and Al were found to have an inverse relationship with prostate cancer and overall metal mixture had no impact on prostate cancer. Since the study was preliminary, these results remain to be confirmed by further large-scale studies.