Background: Prior studies are inconclusive regarding the effect of obesity on mortality in persons with colorectal cancer (CRC). We sought to determine the association of pre-diagnosis body mass index (BMI) trajectories on mortality after CRC diagnosis. Methods: Utilizing the Multiethnic Cohort, we included adults aged 18–75 between 1 January 1993 and 1 January 2019 with a diagnosis of CRC and at least three available BMIs. The primary exposure, BMI, was subjected to group-based trajectory modeling (GBTM). We evaluated all-cause and CRC-specific mortality, using Cox proportional hazard (PH) models. Results: Of 924 persons, the median age was 60 years, and 54% were female. There was no statistically significant association between pre-cancer BMI trajectory and either all-cause or cancer-specific mortality. In competing risk analysis, the risk of CRC-specific mortality was higher for African Americans (HR = 1.56, 95% CI [1.00–2.43],p= 0.048) and smokers (HR = 1.59, 95% CI [1.10–2.32],p= 0.015). Risk of all-cause mortality was higher for Hawaiian persons (HR = 2.85, 95% CI [1.31–6.21],p= 0.009) and persons with diabetes (HR = 1.83, 95% CI [1.08–3.10],p= 0.026). Conclusions: Pre-diagnosis BMI trajectories were not associated with mortality after CRC diagnosis, whereas race/ethnicity, diabetes, and smoking were associated with an increased risk of death. Our findings suggest the obesity paradox alone does not account for mortality after CRC diagnosis.
背景：关于肥胖对结直肠癌（CRC）患者死亡率的影响，既往研究结论不一。本研究旨在探讨诊断前体重指数（BMI）轨迹与CRC诊断后死亡率之间的关联。方法：基于多民族队列研究，我们纳入了1993年1月1日至2019年1月1日期间确诊为CRC、年龄在18-75岁且至少拥有三次BMI记录的成年患者。采用基于群体的轨迹模型（GBTM）对主要暴露因素BMI进行分析，并运用Cox比例风险（PH）模型评估全因死亡率及CRC特异性死亡率。结果：在924例患者中，中位年龄为60岁，54%为女性。诊断前BMI轨迹与全因死亡率或癌症特异性死亡率之间均无统计学显著关联。在竞争风险分析中，非裔美国人（HR = 1.56，95% CI [1.00–2.43]，p = 0.048）和吸烟者（HR = 1.59，95% CI [1.10–2.32]，p = 0.015）的CRC特异性死亡风险更高。夏威夷原住民（HR = 2.85，95% CI [1.31–6.21]，p = 0.009）和糖尿病患者（HR = 1.83，95% CI [1.08–3.10]，p = 0.026）的全因死亡风险更高。结论：诊断前BMI轨迹与CRC诊断后死亡率无显著关联，而种族/民族、糖尿病和吸烟与死亡风险增加相关。本研究提示，肥胖悖论本身并不能完全解释CRC诊断后的死亡率差异。
肿瘤(癌症)患者之家