Published: September 29, 1992
Farmers have higher rates of several deadly forms of cancer, possibly because of exposure to pesticides and other substances and long hours out in the sun, National Cancer Institute researchers say.
Over all, farmers were found to be much healthier than others, with lower rates of heart disease and lung cancer. That is probably because they smoke less and get a lot more exercise, said Dr. Aaron Blair, one of the study’s authors.
“What’s striking is that out of this peaks,” he said last week.
Dr. Blair and his cancer institute colleagues, including Dr. Joseph F. Fraumeni Jr., found that farmers had increased rates of Hodgkin’s disease, multiple myeloma, leukemia, melanoma and cancers of the lip, stomach and prostate. The melanoma and lip cancers are probably due to farmers’ exposure to ultraviolet radiation in sunlight, Dr. Blair said.
He said pesticides were a likely cause of some of the other cancers; other possible causes are fertilizer in drinking water; fuels and oils; fumigants, and animal cancer viruses. Pesticides may be interfering with the farmers’ immune systems, allowing tumors to gain a foothold, he suggested. “Pesticides affect the immune system in a number of animals,” he said. “These aren’t hard links, you understand, but it’s more of a suggestion of one of the things that might be going on.”
John McCarthy, vice president for science of the National Agricultural Chemicals Association in Washington, said: “If you add up all the evidence, we don’t believe there’s a cancer-pesticide association from proper use. But if there are better studies to be done to clarify that, let’s do them.”
Dr. Devra Lee Davis, a scholar at the National Academy of Sciences who studies environmental causes of changing cancer rates, has collaborated with Dr. Blair on a forthcoming study that confirms many of the findings in Dr. Blair’s work, which appears in the current issue of the Scandinavian Journal of Work, Environment and Health.
The cancer institute study was an analysis of some two dozen studies from around the world, Dr. Blair said. The studies were mathematically analyzed to look for trends that might not be apparent in each study individually.