Men who are regularly exposed to organochlorine pesticide metabolites, such as DDE, are at an increased risk of developing testicular germ cell tumours, a new study has indicated.
Earlier studies have revealed that persistent exposure to organochlorine pesticides may increase the risk for some types of testicular cancer, but no evidence was found to establish the observation.
In the current study, led by Katherine McGlynn, Ph.D., of the National Cancer Institute in Bethesda, Md., researchers measured the amount of pesticides or their metabolic breakdown products in blood samples from men who were later diagnosed with testicular germ cell tumors and in blood samples from healthy controls.
All the men in the study were part of the U.S. Servicemen's Testicular Tumor Environmental and Endocrine Determinants study. In addition, the 915 control subjects and 739 case subjects had donated blood samples an average of 14.2 years prior to the current analysis.
Then, the researchers divided the participants into quartiles based on the concentration of a particular pesticide in their blood. And the researchers observed a trend for an increased risk of testicular cancer in men with higher concentrations.
In fact, the trend reached statistical significance for some of the pesticides and metabolites tested. For example, men in the highest quartile for DDE (p,p'-dichlorodiphenyldichloroethylene)--which is a persistent metabolite of DDT (p,p'-dichlorodiphenyltrichloroethane)--were 1.7 times more likely to develop testicular germ cell tumors than those with the lowest concentration.
"If the relative risks calculated in this study are accurate, the population-attributable risk of DDE (i.e., the propor¬tion of disease in the study population that is attributable to DDE exposure) would be approximately 15 percent for all [testicular germ cell tumors]," wrote the authors.