TUESDAY, Sept. 25, 2007 (HealthDay News) -- People newly diagnosed with coronary artery disease had nearly double the normal incidence of colorectal tumors and cancers, a study by Hong Kong researchers found.
Both the tumors and the heart disease "probably develop through the mechanism of chronic inflammation," said the report by researchers at the University of Hong Kong that's published in the Sept. 26 issue of the Journal of the American Medical Association.
But U.S. experts said the risk factors for both diseases are remarkably similar.
"A high-fat diet, a high-protein diet, a sedentary lifestyle," said Dr. Randall W. Burt, director of prevention and outreach at the University of Utah Huntsman Cancer Institute. "We know that the same factors that are important for coronary artery disease are important for colon cancer risk. What they [the Hong Kong researchers] have done is put the two together."
Colorectal cancer is the second most common malignancy worldwide, developing in about one of every 20 individuals. Coronary artery disease is the leading cause of death in the United States and other industrialized countries.
The Hong Kong researchers performed colonoscopies -- inspections of the intestinal tract -- on 206 persons diagnosed with coronary artery disease (CAD) after undergoing angiography, and 208 CAD-negative individuals who had the same test. A 207-member control group was recruited from the local population.
The researchers found colorectal cancers, half of them in the early stages, in 34 percent of the CAD-positive participants, compared to 18.8 percent of those without coronary artery disease. The incidence in the general-population group was 20.8 percent.
Dr. Carl J. Pepine, chief of the division of cardiovascular medicine at the University of Florida at Gainesville, said the findings don't prove that coronary artery disease causes colorectal cancer, or vice versa. "It might just be that a cluster of conditions, including smoking and diabetes, may underlie both conditions," he said.
Another clue is that aspirin can help prevent both coronary artery disease and colorectal cancer, he said.
Previous reports have indicated an association between the two diseases, and "this is one of the better-done studies," Pepine said. "So, it is not original but confirmatory of some other people's work."
The report adds another reason to take steps against the known risk factors for coronary artery disease, Burt and Pepine agreed.
The risk factors for coronary disease are outlined by the American Heart Association.