In a study of more than 100 Swedish men recruited for the study from 1997 to 2000, researchers analyzed blood samples for concentrations of 38 organochlorines. They studied 61 men with testicular cancer and 58 similarly aged men without cancer as controls. To test the potential connection between fetal exposure to pollutants and incidence of testicular cancer, the researchers also performed similar analysis on the men's mothers. The study authors theorized that current levels of these substances in the mothers would correspond with their levels during pregnancy.

There was little difference in organochlorine blood levels between the case men and the control men, with the exception of one pollutant, cis-nonachlordane, which was significantly increased in the cases. The case mothers, however, showed significantly increased concentrations of total organochlorines relative to the control mothers. The editors of EHP classified it as an important study, but caution against drawing conclusions without further review of the issue.

"The theory that testicular cancer is initiated during the fetal period is an important one, and this study certainly suggests an association between exposure and cancer that is worthy of further study," says Dr. Jim Burkhart, science editor for EHP. "Because of the long period between the potential cause and the incidence of cancer, the researchers faced immediate challenges. But with the long half-life of many of these pollutants, current levels of exposure may correlate with exposure levels during child-bearing years. What we know for sure is that this is worth continuing to examine."

The researchers analyzed the data for other factors, including body mass index, length of breastfeeding, and smoking, but found no significant changes to the results.

Even if exposure in utero is found to lead to testicular cancer, the researchers can point to some positive developments: "The concentration of persistent organic pollutants in mothers' milk reflects the body burden," the study authors wrote. "Decreasing concentrations of many of these [pollutants] have been found in Swedish breast milk since the 1980s. The highest concentrations were found in the early 1970s. Because the median age among the cases was 30 years, most of them were born during the period with high concentration in the populations."

The study team was lead by Lennart Hardell of the Department of Oncology at University Hospital in Orebro, Sweden. Other team members included Bert van Bavel, Gunilla Lindstrom, Michael Carlberg, Ann Charlotte Dreifaldt, Hans Wijkstrom, Hans Starkhammar, Mikael Eriksson, Arne Hallquist, and Torgny Kolmert.

EHP is the journal of the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. More information is available online at http://www.ehponline.org/.