Colorectal neoplasms are nearly twice as common in patients newly diagnosed as having coronary artery disease than in those found not to have CAD based on coronary angiography, results of a cross-sectional study suggest.
The prevalence of colorectal neoplasms in patients with CAD in their study was nearly three times as high as that reported in the general population in either Hong Kong or the United States, investigators reported.
Dr. Annie On On Chan of the University of Hong Kong and her associates previously published a retrospective study showing a strong association between colorectal neoplasms and CAD. To further examine this link, they conducted a cross-sectional study of consecutive patients who were undergoing coronary angiography to assess suspected CAD, followed by colonoscopy.
In industrialized Hong Kong, incidence rates of colorectal cancer and CAD, and mortality from the conditions, are similar to the rates in Western countries, they noted.
The study included 206 patients who were found to have CAD, 208 patients who were found not to have CAD, and a control group of 207 people from the general Hong Kong population who were matched to the other subjects based on age and sex. The family histories of colorectal cancer were similar among the three groups.
Colonoscopy revealed that colorectal neoplasms were more prevalent in the CAD-positive group (34%) than in the CAD-negative group (18%) or the control group (20%).
This 34% prevalence in patients newly diagnosed as having CAD was especially “remarkable,” compared with the current prevalences reported in the general population in Hong Kong (12%) and the United States (10%), Dr. Chan and her associates said (JAMA 2007;298:1412–9).
Similarly, the prevalences of advanced colorectal lesions and adenocarcinomas were much higher in the patients with CAD (18% and 4%, respectively) than in the patients who didn't have CAD (6% and 0.5%) or the control subjects (5% and 1%).
The reason for this association between CAD and colorectal neoplasm is not yet known, but it is possible that the two disorders share common environmental risk factors. Moreover, both disorders have been linked to metabolic syndrome and smoking, and both “probably develop through the mechanism of chronic inflammation,” the investigators said.
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