Cadmium Levels in Tissue and Plasma as a Risk Factor for Prostate Carcinoma: a Meta-Analysis.

Cadmium is a heavy metal that has been suggested to be a carcinogen by evidence. A number of published studies have investigated the association between cadmium levels and prostate cancer, but the results were inconsistent. Thus, we conducted a meta-analysis to get a precise estimate of this subject. After a careful searching and screening, a total of 11 publications containing 14 separated studies were included. Based on a random-effect model, the pooled data showed that cadmium levels of prostate tissues (standard mean difference (SMD) = 3.17, 95 % confidence interval (CI) = 0.60-5.74, P < 0.05) and plasma (SMD = 4.07, 95 % CI = 2.01-6.13, P < 0.05) were significantly higher in prostate cancer patients than those in the healthy controls. No difference of hair and nail cadmium levels between the prostate cancer cases and the controls was found. The data suggested that cadmium exposure might exert an influence on the tumorigenesis of prostate tissues. Future investigations with large sample sizes are needed to verify the results.