NCPA - National Center for Policy Analysis


December 19, 2005

Trying to determine the relationship between the environment and cancer has proven to be vexing. The main problem is trying to decide which chemicals might be causing cancer, and in whom, says the New York Times' Gina Kolata.

Since 1993, researchers have studied farmers and their spouses in Iowa and North Carolina, including what pesticides and herbicides they use, when did they use them and how much did they use; they also obtained information on other risk factors like smoking, says Kolata.

According to researchers, few associations have been found, but nothing is definitive:

  • None of the results are large enough for any regulatory agency to take action or to say they are a human carcinogen.
  • They are just leads, including: a slightly higher rate of lung cancer and leukemia in farmers who used the insecticide diasinon and a possible increase in prostate cancer among farmers who used methylbromide to fumigate the soil.
  • Investigators also looked for an association between pesticides, herbicides and breast cancer, but they didn't find one.

Moreover, even if the researchers found that some chemicals have increased farmers' cancer rates, it would still remain unclear what that means for the general population where exposures are usually much lower, and whether or not those chemicals should be banned, says Kolata.

Furthermore, in the last 50 years, cancer rates have steadily dropped and what appears to be increases in breast and prostate cancer are just the results of increased screenings; pollution is not a major determinant of U.S. cancer rates, says Kolata.

Source: Gina Kolata, "Environment and Cancer: The Links Are Elusive," New York Times, December 13, 2005.

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