PurposeThis study was conducted to determine the distributions of the polyp detection rate (PDR) and the adenoma detection rate (ADR) according to age by analyzing the polypectomy results.MethodsA total of 10,098 patients who underwent a colonoscopy in 2013 were included in this study. Chi-square and logistic regression statistical analyses were performed using SPSS ver. 19.ResultsThe mean age of the patients was 52.7 years old (median, 54 ± 12.52 years; range, 14 to 92 years). A total of 6,459 adenomatous polyps (61.7%) from a total of 10,462 polyps were eliminated. The PDR was 50.9% (5,136/10,098), and the. ADR was 35.4% (3,579/10,098). The male-to-female ratio was 51.3%:48.7%, with a male-to-female ADR ratio of 42.8% : 27.7% (P < 0.001). In the age distribution, the values of the ADR were 0% for patients in their 10's, 6.3% for those in their 20's, 14.0% for those in their 30's, 28.7% for those in their 40's, 38.4% for those in their 50's, 46.2% for those in their 60's, 55.8% for those in their 70's, 56.1% for those in their 80's, and 33.3% for those in their 90's. In males, the values of the ADR were 0%, 9.1%, 17.1%, 37.8%, 48.2%, 53.6%, 61.7%, 59.1%, and 33.3% for the same age distribution, and a steep increase was found between patients in their 30's and patients in their 40's. Significant (P < 0.001) factors influencing the ADR included sex, previous colonoscopy experience, polypectomy method, and age of more than 40 years.ConclusionIn considering the adenoma carcinoma sequence, 28.7% of people, especially 37.8% of males in their 40's showed adenomatous polyps. Whether an earlier first-time colonoscopy will have better results in preventing colorectal cancer should be investigated and discussed.