The history and current status of the perceived relationship between saccharin (81072) and human bladder cancer was reviewed. A Canadian animal study from 1977 was the first of several recent evaluations of a possible cancer causing potential of saccharin. Positive findings were found in both male and female rats, but only those in males were statistically significant. In the same year, a Canadian epidemiological study, which was later severely criticized, showed positive findings for men, but not for women. As a result, the Food and Drug Administration proposed a ban of saccharin in the United States. However, older studies as well as new epidemiological ones carried out in the United States and Europe were negative, but when a study in rats supported the Canadian results, the ban was enacted. The author points out the lessons that might be drawn from the regulatory discussions on saccharin. It is emphasized that an assessment of exposure is very difficult for compounds that form such an integral part of many people's diet as did saccharin. The observation that almost all of the saccharin studies are clustered around the null state, weakly positive or weakly negative, is another problem. The author discusses how scientists, regulators, and policy makers react to the near null state, and he concludes that these considerations are crucial for valid risk estimations.
Proceedings of a Symposium on Epidemiology and Health Risk Assessment, Columbia, Maryland, May 14-16, 1985, Centers for Disease Control/NIOSH, 12 pages