The incidence of colorectal cancer (CRC) has been steadily rising, and obesity has been identified as a significant risk factor. Numerous studies suggest a strong correlation between excess body weight and increased risk of CRC, but comprehensive quantification through pooled analysis remains limited. This study aims to systematically review and meta-analyze the existing literature to evaluate the association between obesity and CRC risk, considering variations across sex and study designs. A systematic literature search was conducted in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science to identify randomized controlled trials and human clinical trials from 1992 to 2024. Statistical analysis was performed using the https://metaanalysisonline.com web application using a random effects model to estimate the pooled hazard rates (HR). Forest plots, funnel plots, and Z-score plots were utilized to visualize results. We identified 52 clinical trials and 14 case–control studies, encompassing a total of 83,251,050 and 236,877 subjects, respectively. The pooled analysis indicated that obesity significantly increased the prevalence of CRC (HR = 1.36, 95% CI = 1.24–1.48, p < 0.01). This effect was consistent across sexes, with HRs of 1.57 (95% CI = 1.38–1.78, p = 0.01) for males and 1.25 (95% CI = 1.14–1.38, p < 0.01) for females. Case–control studies specifically showed an effect, but with marginal significance only (HR = 1.27, 95% CI = 0.98–1.65, p = 0.07). The Z-score plot indicated the need for additional analysis in the case–control group. A significant heterogeneity was observed across studies in all four settings. This meta-analysis provides robust evidence that obesity is a significant risk factor for colorectal cancer, with an overall hazard rate indicating a 36% increased risk. The effect is pronounced across both sexes, with males showing a slightly higher risk compared to females. Although case–control studies showed a weaker association, the overall trend supports the link between obesity and CRC. These results underscore the importance of public health interventions aimed at reducing obesity to potentially lower the risk of colorectal cancer.

结直肠癌 （CRC） 的发病率一直在稳步上升，肥胖已被确定为一个重要的危险因素。大量研究表明，超重与 CRC 风险增加之间存在很强的相关性，但通过汇总分析进行的综合量化仍然有限。本研究旨在系统回顾和荟萃分析现有文献，以评估肥胖与 CRC 风险之间的关联，同时考虑性别和研究设计的变化。在 PubMed、Cochrane 对照试验中心注册库 （CENTRAL） 和 Web of Science 中进行了系统文献检索，以确定 1992 年至 2024 年的随机对照试验和人体临床试验。使用 https://metaanalysisonline.com Web 应用程序使用随机效应模型进行统计分析，以估计合并风险率 （HR）。森林图、漏斗图和 Z 分数图用于可视化结果。我们确定了 52 项临床试验和 14 项病例对照研究，分别涉及 83,251,050 名和 236,877 名受试者。汇总分析表明，肥胖显着增加了 CRC 的患病率 （HR = 1.36,95% CI = 1.24–1.48，p < 0.01）。 这种影响在性别之间是一致的，男性的 HR 为 1.57 （95% CI = 1.38-1.78，p = 0.01），女性为 1.25 （95% CI = 1.14-1.38，p < 0.01）。病例对照研究特别显示了效果，但仅具有边际意义 （HR = 1.27,95% CI = 0.98–1.65，p = 0.07）。 Z 分数图表明病例-对照组需要进行额外分析。在所有四种情况下的研究中都观察到显著的异质性。 这项荟萃分析提供了强有力的证据表明，肥胖是结直肠癌的重要危险因素，总体风险率表明风险增加 36%。这种影响在两性中都很明显，与女性相比，男性表现出的风险略高。尽管病例对照研究显示相关性较弱，但总体趋势支持肥胖与 CRC 之间的联系。这些结果强调了旨在减少肥胖以潜在降低结直肠癌风险的公共卫生干预措施的重要性。