体重指数与年龄交互作用对乳腺癌患者预后影响的研究

背景与目的： 目前已有研究表明体重指数（body mass index,BMI）是乳腺癌患者预后的影响因素。本研究旨在分析不同年龄段的乳腺癌患者的BMI与其死亡风险的关联。方法： 回顾性收集2008年1月1日—2016年12月31日在复旦大学附属肿瘤医院住院治疗的25 629例初诊乳腺癌患者的临床特征和生存状况,经调整主要预后影响因素,以限制性立方样条Cox比例风险回归模型分析在不同年龄亚组中BMI与乳腺癌患者预后的关联。结果： BMI与年龄均为乳腺癌预后的影响因素,且存在显著的交互作用。不同年龄组患者的死亡风险与BMI的关联模式有所不同。在年龄小于35岁组观察到死亡风险与BMI呈现“J”型的关联,BMI为20.16 kg/m²的患者死亡风险最低;在年龄35 ~ 60岁组观察到BMI在23 kg/m²以下的患者死亡风险随着BMI的增加没有明显变化,BMI在23 kg/m²以上的患者死亡风险随着BMI的增加而增加;而在年龄大于60岁组观察到死亡风险与BMI呈现“U”型的关联,BMI为23.86 kg/m²的女性死亡风险最低。年龄小于35岁组患者的死亡风险对BMI变化的敏感程度相较于年龄35 ~ 60岁组和大于60岁组更高。结论： 在校正了相关预后因素后,BMI与年龄对乳腺癌患者预后的影响有显著的交互作用,不同年龄组患者的死亡风险与BMI的关联模式有所不同,对于年轻患者,死亡风险最低对应的诊断时BMI约为20 kg/ m²,而对于60岁以上患者,死亡风险最低对应的诊断时BMI约为24 kg/m²。

The effect of the interaction between body mass index and age on the prognosis of breast cancer

Background and purpose: Currently, several studies have demonstrated that body mass index (BMI) is a prognostic factor in breast cancer. The study aimed to assess the association pattern of BMI with mortality risk among patients of different age groups. Methods: This retrospective cohort study included the clinical characteristics and survival status of 25 629 patients diagnosed with breast cancer and subsequently hospitalized in Fudan University Shanghai Cancer Center between January 1, 2008 and December 31, 2016. The association between BMI and prognosis of breast cancer patients in different age subgroups was analyzed using Cox proportional hazards regression model with restricted cubic splines adjusting the main prognostic factors. Results: BMI and age were both influencing factors of breast cancer prognosis, and there was a significant interaction (P = 0.011). The pattern of association between risk of death and BMI differed among different age groups. A "J-shaped" association between risk of death and BMI was observed in the patients younger than 35 years, with a BMI of 20.16 kg/m² corresponding to the lowest risk of death. In the age group of 35-60 years, no significant change in the risk of death was observed in patients with BMI below 23 kg/m², and the risk of death in patients with BMI above 23 kg/m² increased with increasing BMI; A "U-shaped" association between risk of death and BMI was observed in the patients older than 60 years, with a BMI of 23.86 kg/m² being the lowest. The risk of death was more sensitive to changes in BMI in patients aged less than 35 years than in those aged 35-60 years and those aged more than 60 years. Conclusion: BMI and age have a significant interaction in the prognosis of breast cancer when adjusted for potential confounding factors. The association pattern between the risk of death and BMI of patients in different age groups is different. For patients under 35 years old, the lowest risk of death corresponds to BMI at diagnosis of about 20 kg/m², while for patients over 60 years old, the lowest risk of death corresponds to a BMI at diagnosis of about 24 kg/m².