Risk factors for colorectal neoplasia in persons aged 30 to 39 years and 40 to 49 years

Background: Very little is known about risk factors associated with colorectal neoplasia in persons aged <50 years. In particular, there has been no study thus far focusing on the risk factors for colorectal neoplasia in persons aged 30 to 39 years. Objective: To investigate risk factors for colorectal neoplasia in persons aged 30 to 39 years and 40 to 49 years and to compare those data with those of persons aged 50 to 59 years. Design: Cross-sectional observational study. Setting: Screening center in a university hospital in Korea. Patients: A cohort of 28,504 Korean adults (13,678 aged 30-39 years, 12,507 aged 40-49 years, and 2319 aged 50-59 years) who underwent colonoscopy as part of their routine preventive health care. Interventions: Colonoscopy. Main Outcome Measurements: Risk factors for colorectal neoplasia in persons aged 30 to 39 years and 40 to 49 years. Results: In the 30-to-39 -years group, male sex, smoking, fatty liver, metabolic syndrome (MetS), obesity, elevated fasting blood glucose levels, and elevated triglyceride levels were associated with overall neoplasia, whereas for advanced neoplasia, the independent risk factors were smoking, fatty liver, and elevated triglyceride levels. Moreover, the prevalence of overall neoplasia in men aged 30 to 39 years exhibiting all risk factors was not lower than that in average-risk women aged >50 years (20.8% vs 18.8%; P = .546). The risk factors of overall neoplasia in the 40-to-49-years group were similar to those in the 30-to-39-years group. For advanced neoplasia, the independent risk factors in the 40-to-49-years group were male sex, smoking, MetS, and obesity. Limitations: Selection bias may exist for participants of ethnic Korean heritage in 2 centers. Conclusion: Obese male smokers with fatty liver and MetS might benefit from screening colonoscopy starting before age 50 years.