Fluoride & Liver Cancer
in National Toxicology Program (NTP)
Summation from Dr. John Yiamouyiannis:
"In 1977, Congress instructed the U.S. Public Health Service to conduct animal studies to determine whether or not fluoride causes cancer. As a result, the National Toxicology Program retained the Battelle Memorial Institute in Columbus, Ohio to perform two studies, one on mice, and another on rats.
Doctor John T. Toft, II, manager of the Pathology Section at Battelle, was placed in charge of the NTP mouse study. On October 28, 1988, after a year of analyzing these results, Doctor Toft completed the pathology narrative and final report.
The most significant finding was the occurrence of an extremely rare form of liver cancer, hepatocholangiocarcinoma in fluoride-treated male and female rats — mice, excuse me.
Among male mice, no such cancers were observed among 79 in the control group. At 11 parts per million, the lowest dose used, one was observed among 50 male mice; and 45 parts per million, one was observed among 51 male mice and at seventy-nine parts per million three were observed among 80 male mice.
Using historical controls and doing a binomial analysis of this, the odds of these results occurring by chance are less than one in two million. Normally, we consider it significant one in twenty; this is one in two million.
Making these findings even more convincing are the results with female mice. In the control group, no hepatocholangiocarcinomas were observed among eighty. At 11 parts per million, one was observed among 52. At 45 (ppm), none were observed among 50. And at 79 parts per million, three were observed among 80 female mice — female mice.
Based on these findings, and these findings alone, there was clear evidence of the carcinogenic activity of the fluoride in mice receiving 11, 45, or 79 parts per million in drinking water for two years or less."
SOURCE: Yiamouyiannis J. (1990). Testimony before Board of Scientific Counselors, National Toxicology Program; Peer Review of Draft Technical Report of Long-Term Toxicology and Carcinogenesis Studies and Toxicity Study, Sodium Fluoride; Research Triangle Park, North Carolina, Thursday, April 26, 1990.