The hour of weekly exercise lowered the risk of adenomas in people who were overweight and who were black. The risk of cancer was also lowered in black study participants.
Also, "individuals who exercised for at least three years had increased protection from colon polyps," said Sanchez, who spoke at an April 21 news conference on the research.
"Nobody knows why there's a benefit from exercise," Weinberg said. "You can come up with a couple of reasonable hypotheses. Is it because you're altering some important set of biological pathways? There's a lot of data that link obesity and polyps. Does that operate through insulin and insulin growth factors?"
The findings, added Sanchez, "have a great public health impact."
Now the job is to determine exactly which exercises are the most beneficial, he said.
Because the study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
The U.S. National Cancer Institute has more on colon cancer.
SOURCES: David Weinberg, M.D., chairman, medicine, Fox Chase Cancer Center, Philadelphia; April 21, 2011, teleconference with Nelson Sanchez, M.D., attending physician, Memorial Sloan-Kettering Cancer Center, New York City
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