Children who eat more than 12 hot dogs per month have nine times the normal risk of developing childhood leukemia, a USC epidemiologist has reported in a cancer research journal. Two other reports in the same issue of Cancer Causes and Control suggest that children born to mothers who eat at least one hot dog per week during pregnancy have double the normal risk of developing brain tumors, as do children whose fathers ate hot dogs before conception.

The recent findings, which are generating a great deal of controversy and concern, could help explain why the incidence of childhood leukemia and brain tumors has been increasing over the last two decades, say the researchers, led by USC epidemiologist John Peters.

The scientists caution that the studies are preliminary and based on relatively small numbers of cases--a total of 621 cancer victims in the three studies and an equal number of controls. They also note that the statistical association is not necessarily a cause-and-effect relationship.

Critics, as well as the researchers themselves, point out that such studies are difficult to conduct and interpret because people have a hard time recalling what they have eaten.

Nonetheless, the scientists argue that the results are significant and the issue deserves much more intensive scrutiny. In response to the findings, researchers at the University of Minnesota have modified their National Cancer Institute-sponsored study on childhood leukemia to explore the possible connection to hot dogs.

The researchers suggest that the trigger for the cancers might be the nitrites used to preserve processed meats such as hot dogs. Nitrites are converted in the body to highly carcinogenic nitrosamines.

Still, none of the investigators argue that people should stop eating hot dogs based on the findings.

Because of the low incidence of these childhood tumors, "this is not a hazard at the level of tobacco smoke or high-fat diets," said epidemiologist David Savitz of the University of North Carolina, author of one of the studies on pregnant women. "The rational response would be a small modification of your consumption."

"It's an intriguing idea because hot dogs certainly contain chemicals that one might wonder about," said Dr. Clark Heath, vice president for medical research of the American Cancer Society. "I don't think they prove the case," he said, but the results are feasible because animal studies have established that nitrites cause cancer. "Obviously, it is an idea that will need to be explored further."