Cadmium exposure is a known risk factor for prostate cancer, and a new University of Rochester study suggests that zinc may offer protection against cadmium.
In an article published in the February 2008 journal, The Prostate, epidemiologist Edwin van Wijngaarden, Ph.D., reports that PSA levels were 22 percent higher among American men who had zinc levels below the median (less than 12.67 mg/daily) and cadmium levels above the median. (PSA is a protein produced by the cells of the prostate gland. The higher a manís PSA level, the more likely cancer is present.)
In contrast, among men with a greater than median zinc intake, little evidence of an association between cadmium and PSA was found.
This result seems especially important for cigarette smokers who breathe in cadmium on a daily basis.
The result is plausible because there is a biological mechanism by which zinc provides protection.
The way zinc and cadmium interact within human organs is significant and provides interesting leads for study, van Wijngaarden said. Zinc stimulates production of a protein that binds cadmium thereby taking it out of circulation and reducing its toxic effects.
Sex hormones circulating in the blood do not appear to be associated with prostate cancer risk, according to data from 18 prior studies. The analysis will be published online January 29 in the Journal of the National Cancer Institute.
Having high levels of male sex hormones, known as androgens, has long been hypothesized as a risk factor for prostate cancer. Nearly two dozen prospective studies have examined the relationship between circulating sex hormones and prostate cancer risk, but the results have been inconsistent.
Andrew Roddam, D.Phil., of the University of Oxford in England and colleagues at the Endogenous Hormones and Prostate Cancer Collaborative Group collected the original data from 18 studies and analyzed it to determine the relationship between blood levels of sex hormones and prostate cancer. The pooled data included 3,886 men with prostate cancer and 6,438 controls.
The researchers found no association between prostate cancer risk and blood levels of different forms of testosterone or estrogen.
|Share |||Randall Parker, 2008 January 30 10:05 PM Aging Diet Cancer Studies|