New York Times
11 November 2002

Sperm Quality Low in Farming Region
By THE ASSOCIATED PRESS

ST. LOUIS (AP) -- A study has found the quality of semen significantly poorer in men from rural mid-Missouri than in males from urban areas, and its authors believe agricultural chemicals might explain the difference.

The University of Missouri researchers said their study offered the first convincing evidence that semen quality -- measured by the count, shape and movement of sperm -- varies significantly among regions of the United States.

The study appeared in Monday's online edition of Environmental Health Perspectives, a publication of the National Institute of Environmental Health Sciences.

Fertile men from mid-Missouri's Boone County were found to have a mean sperm count of about 59 million per milliliter, compared to 103 million for men in New York, 99 million in Minnesota and 81 million in Los Angeles. The sperm of the Boone County men also tended to be less vigorous, the study found.

Dr. Shanna Swan of the University of Missouri-Columbia, the lead researcher, said she and her collaborators believe that environmental factors such as the use of agricultural chemicals might contribute to the differences.

Farms make up more than half of Boone County, and most use chemical fertilizers, herbicides or pesticides. In contrast, 0 to 19 percent of the urban areas studied were devoted to farming.

The researchers studied 512 couples receiving prenatal care at clinics in Columbia, Minneapolis, Los Angeles and New York as part of an ongoing Study for Future Families funded by the National Institutes of Health.

Swan said previous studies of semen quality were conducted in large cities, except for a study in Iowa City, Iowa, that also found lower sperm concentration.

Researchers still do not know why semen quality varies geographically, but are testing their hypothesis that exposure to agricultural chemicals through contaminated air or water plays a role.

The study was conducted in collaboration with researchers at the University of Minnesota, the University of California at Los Angeles Medical Center, the University of California, Davis, and Mount Sinai School of Medicine.