SAN ANTONIO – Colorectal adenomas were significantly more common in adults with type 2 diabetes, compared with the general adult population, based on a study of 860 patients who underwent screening colonoscopy.
“Colonic adenomas and advanced adenomas were independently predicted by diabetes,” wrote Dr. Nisheet Waghray of MetroHealth Medical Center in Cleveland, and colleagues. They presented their findings in a poster Oct. 18 at the annual meeting of the American College of Gastroenterology.
Previous studies have shown a 30%-40% increase in colorectal cancer risk in adults with type 2 diabetes, but the association between type 2 diabetes and the risk of colorectal adenomas has not been well studied, the investigators said.
The researchers reviewed colonoscopy data from 269 adults with type 2 diabetes and 591 adults without diabetes who were screened at a single medical center between January 2007 and January 2010.
All of the following findings – three or more adenomas, adenomas larger than 1 cm, a proximal location of advanced adenomas, and a higher mean number of polyps – were significantly more common in the diabetes patients than in the nondiabetics.
The percentage of patients with three or more adenomas was 14% in those with diabetes vs. 10% in the general population, and the rate of adenomas larger than 1 cm was 9.7% and 4.7%, respectively. The average number of polyps in patients with diabetes vs. those without diabetes was 4.9 vs. 2.5. In addition, 68% of advanced adenomas in the diabetes patients were proximal, compared with 31% of those in the general population.
The average age of the patients with diabetes was 57 years, vs. 61 years in the general population, but this difference was not significant. There were no significant differences between the two groups in terms of body mass index, family history of colorectal cancer, or patient use of alcohol, tobacco, or nonsteroidal anti-inflammatory drugs. Approximately 60% of the patients in both groups were black.
The findings suggest that type 2 diabetes influences not only the number of adenomatous polyps, but also their location within the colon. More research is needed to confirm the results, but this study “adds plausibility that diabetes may play a role in the adenoma-carcinoma sequence,” Dr. Waghray and colleagues noted.
The researchers said that they had no financial conflicts to disclose.