摘要Objective To examine the effect of excess body weight on adherence and lesion detection in colorectal cancer(CRC)screening.Methods A cross-sectional analysis was conducted within an opportunistic CRC screening program in Chongqing,which enrolled 43,797 adults aged 35-74 years between 2021 and 2022.A total of 42,279 participants were included in the final analysis,of whom 19,462(46.0%)had excess body weight(BMI>24.0 kg/m2).Colonoscopy adherence and detection were compared between normal and excess body weight group,and associated factors were examined.Results Of the 7,002 participants recommended for colonoscopy,3,808(54.4%)had excess body weight.Adherence was significantly lower in the excess weight group(6.6%)than in the normal weight group(10.7%,P<0.001),and this trend was consistent across sex and age groups.The detection rates of advanced neoplasms(3.6%vs.1.8%)and non-advanced adenomas(10.7%vs.6.7%)were higher in the excess weight cohort,with a significant difference for any neoplasm(14.2%vs.8.9%,P<0.05).Differences in adherence-and detection-related factors were also observed between the groups.Conclusion Excess body weight was associated with lower colonoscopy adherence but higher neoplasm detection.These findings support the integration of weight management with targeted screening promotion to improve CRC prevention in this high-risk population.