The association of sedentary time and physical activity with colorectal adenoma: A colonoscopy-based study.

BACKGROUND: To assess the association of sedentary time and physical activity with the occurrence of colorectal adenomas in asymptomatic participants. METHODS: We conducted a case-control study at Taipei Veterans General Hospital, Taiwan to examine sedentary time, physical activity, and their joint effects on colorectal adenoma risk among asymptomatic participants. Conditional logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Among 5,982 asymptomatic adults undergoing health screening, shorter sedentary time was independently associated with a lower risk of colorectal adenoma (n=3,616), after adjusting for other risk factors, including physical activity. The ORs (95% CIs) for each category of sedentary time >450, 300-450, and <300 minutes/day were 1.00 (reference), 1.10 (0.90-1.34), and 0.52 (0.40-0.69), respectively (p trend <0.001). Joint analysis demonstrated that higher physical activity was associated with a lower risk of colorectal adenoma, particularly among individuals with a sedentary time of 300-450 minutes/day. Moreover, within the moderate- and high physical activity categories, shorter sedentary time was consistently associated with additional risk reduction. A similar pattern was observed for advanced adenoma subgroup. CONCLUSION: Sedentary time was independently associated with increased colorectal adenoma risk, whereas reducing sedentary time may lower advanced adenoma risk and augment the benefits of moderate- to high-physical activity among asymptomatic population in Taiwan.