Prevalence and Risk Factors for Adenomatous Polyps in the Average-Risk Lebanese Population Undergoing Screening Colonoscopy

Abstract

Purpose: Multiple large colonoscopy screening trials in North America and Europe have shown a prevalence of adenomatous polyps of 25-35%. The prevalence of advanced neoplasia (defined as a polyp >1cm, presence of villous histology, high grade dysplasia or cancer) ranges from 3-10% in these studies that included some individuals with a family history of colon cancer. Smoking, alcohol consumption, obesity, and red meat have been reported as possible risk factors for the development of polyps and colon cancer, while calcium, physical activity, NSAID use, and antioxidants have been reported as possible protective factors. This study aims to investigate the prevalence of adenomas and advanced neoplasia in the average-risk Lebanese population and to examine possible associated risk factors and protective factors for colorectal polyps. Methods: Consecutive asymptomatic Lebanese aged ≥ 50 undergoing screening colonoscopy were included. Exclusion criteria included a family history of colon cancer or of large colon polyps. Information about smoking, alcohol use, exercise, dietary habits, and long-term use of NSAIDs, calcium, and hormone replacement therapy in females was collected. Polyp size, number, and location were charted on a colon sketch for each patient and the histopathology confirmed by an experienced pathologist. Results: To date, 500 average-risk individuals (233 males and 267 females, mean age = 61.2±8.3 years) underwent screening colonoscopy by experienced board-certified gastroenterologists. One or more adenomatous polyp(s) were detected in 175 overall patients (35.0%). Advanced neoplasia was noted in 22 patients (4.4%) (15 males and 7 females) including 3 patients who had cancer (0.6%). Mean colonoscopic withdrawal time was 11.0 ± 3.0 minutes. On multivariate analysis using backward stepwise logistic regression, increasing age (p=0.004, OR=1.59 (1.16-2.16)) and increased intake of red meat (p<0.001, OR=1.92 (1.34-2.72)) were found to be risk factors for the development of adenomatous polyps. None of the factors evaluated was found to be significantly protective. Conclusion: The overall prevalence of colorectal adenomas in the average-risk Lebanese population matches that reported in North American and European studies on screening colonoscopies, while the prevalence of advanced neoplasia lies on the lower end of the spectrum. This study confirms the higher risk associated with increasing age noted in larger trials. Intake of red meat, which has been reported as a risk factor for adenomatous polyps in some studies, was also found to be a significant independent risk factor. The role of other risk factors as well as possible protective factors requires further investigation in larger cohorts.