Symptoms and demographic factors associated with early-onset colorectal neoplasia among individuals undergoing diagnostic colonoscopy.

BACKGROUND: The incidence and mortality of colorectal cancer (CRC) are increasing in adults under 50 years. Risk factors associated with early-onset colorectal neoplasia (CRN) are uncertain. We aimed to identify clinical predictors associated with the presence of CRN detected by diagnostic colonoscopy in symptomatic individuals under 50 years of age. METHODS: We used a single-center endoscopy database to identify symptomatic patients 18-49 years of age who underwent ambulatory colonoscopy between 2007 and 2017. Pathology reports identified CRN as adenomas, advanced adenomas (based on size or histology), or adenocarcinomas. Multivariable analysis was used to determine factors associated with CRN. RESULTS: We identified 4333 eligible patients of whom 363 (8.4%) had any CRN and 48 (1.1%) had advanced neoplasia (advanced adenoma or adenocarcinoma). Factors associated with any CRN on multivariable analysis included male sex [odds ratio (OR) 1.50 (1.19-1.88)], older age group [compared to 18-29 years, OR for 30-39: 3.12 (1.93-5.04); OR for 40-49: 4.68 (2.97-7.36)], obesity [OR for BMI 30-34.9 compared to 18-24.9: 1.44 (1.04-2.01)], and any tobacco use [OR 1.63 (1.18-2.23)]. Anemia was associated with advanced neoplasia [OR 3.11 (1.32-7.34)]. Of the advanced neoplastic lesions, 38 of 48 (79.2%) were located in the distal colon. CONCLUSIONS: In the largest study to date of symptomatic individuals under 50 years of age undergoing colonoscopy in the USA, advanced CRN was most often detected in the distal colon and was associated with anemia, but not with abnormal bowel habits or abdominal pain. We also found that patients with CRN under 50 years of age were more likely to be male, smokers, and obese. These findings should prompt further investigation of these risk factors alone and in combination.