Résumé :
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Shellfish consumers are exposed to the risk of diarrhea from, among other contaminants, algea that produce diarrhetic shellfish poisoning (DSP) toxins, such as Dinophysis spp. These illnesses have been effectively prevented since 1984, when a phycotoxin monitoring network was set up along the coasts of France. There is nonetheless concern that residual levels of okadaic acid, a known tumor promoter that is the main toxin present in French coastal waters, might increase the risk of cancer among regular shellfish consumers. To test this hypothesis, we conducted an ecological study linking digestive cancer mortality rates with a proxy measure of contamination by DSP toxins in 59 coastal areas ; Observed and expected numbers of deaths (using national rates as reference) were computed by sex, cause of death, and area for two time periods : 1984-1988 and 1989-1993. The level of contamination in each area was estimated by the total number of weeks since monitoring began that production was shut dowwn because of DSP toxin contamination. Using both Poisson regressions and test for trends of standardized mortality ratios across four exposure categories, we found some evidence of associations for several digestive cancer sites. (R.A.).
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