Gallstones a Risk Factor for Colorectal Adenoma

NEW YORK DEC 04, 2008 (Reuters Health) - Among subjects undergoing colonoscopy screening, cholelithiasis is associated with an increased risk of colorectal adenoma, findings published in the November issue of the American Journal of Gastroenterology indicate.

Many studies "have reported a moderately increased risk of colorectal cancer in patients with cholecystectomies," note Dr. Yutaka Yamaji, of the University of Tokyo, Japan, and colleagues write. "In contrast, few reports have been published regarding colorectal adenoma, a precursor of cancer." Moreover, they note, "Very few studies have investigated the association between cholelithiasis without resection and colorectal adenoma, but data indicate that the two are not related."

The researchers therefore examined the association between cholelithiasis and colorectal adenoma in 4458 subjects (3053 men, 1405 women) who underwent both ultrasonography and colonoscopy, and completed a questionnaire on lifestyle habits.

Overall, 4189 subjects had normal gallbladders while cholelithiasis was detected in 206 subjects and 63 had cholecystectomies.

The prevalence of colorectal adenoma was 29.6% in cholelithiasis patients, significantly higher than the 17.7% prevalence in subjects with normal gallbladders (p < 0.001). Only 15.9% (10/63) of cholecystectomy patients developed colorectal adenomas, which was not significantly different from control patients.

Cholelithiasis was an independent risk factor for colorectal adenoma (adjusted odds ratio, 1.57) in a multivariate analysis controlling for sex, age, family history of colorectal cancer, alcohol, smoking, and body mass index.

A strong association was observed between cholelithiasis and the presence of at least 3 lesions (adjusted OR 2.39) and left-sided colorectal adenomas (adjusted OR 1.82).

"We did not detect an association between cholecystectomy and colorectal adenoma, but silent cholelithiasis and colorectal adenoma were related," Dr. Yamaji and colleagues conclude. "Although the mechanism of this association is unclear, it is possible that the carcinogenic properties of bile acid may play a role."

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