Background: Colorectal cancer (CRC) prevention relies on early diagnosis and endoscopic resection of adenomatous polyps. This in turn depends on the quality of the performed colonoscopy. "Polyp detection rate, PDR" and "adenoma detection rate, ADR" are considered indices for quality of colonoscopy. This study aims to evaluate PDR and ADR, alongside the demographic, clinical, and pathological characteristics of colorectal polyps in an Iranian population. We also aimed to find the prevalence of colon polyps among different age groups.

Methods: All consenting patients 40 years of age or older undergoing screening colonoscopy or for possible IBS in a referral center in Tehran over 10 years were enrolled. We collected demographic data, quality of colon preparation, time to cecum, withdrawal time and colonoscopic findings. PDR and ADR were calculated and correlated with the above-mentioned indices.

Results: A total of 3,416 (mean age 57.6 ± 9.8 years) people meeting the inclusion criteria were enrolled. Successful ileal intubation occurred in 54.6%. PDR was 41.5% (95% CI: 39.9-43.3%) being higher in men (46.8% vs. 36.9%; p = 0.01). Individuals aged 45-49 years exhibited a greater likelihood of colorectal polyps than younger counterparts (34.2% vs. 21.9%, p = 0.001). Overall ADR was 26.4% (95% CI: 25.01-27.9%), with patients older than 50 years having a higher rate (29.3% vs. 16.3%).

Conclusion: Our data shows acceptable PDR and ADR in this referral center and higher prevalence of adenomatous polyps in men in accordance with western reports. In addition, according to our data substantial proportion of individuals aged 45-49 years were found to harbor adenomatous polyps, aligning with trends observed in Western populations. If further research confirms these findings, it could provide a rationale for considering the initiation of colorectal cancer screening at age 45 in Iran.