Du Yun, Feng Ruimei, Chang Ellen T, Yin Li, Huang Tingting, Li Yancheng, Zhou Xiang, Huang Yi, Zhou Feng, Su Canqiong, Xiao Xue, Jia Weihua, Zheng Yuming, Adami Hans-Olov, Zeng Yixin, Cai Yonglin, Zhang Zhe, Xu Miao, Ye Weimin
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Department of Epidemiology and Health Statistics and Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou, China.
Int J Cancer. 2023 Jul 15;153(2):290-301. doi: 10.1002/ijc.34524. Epub 2023 Apr 7.
A concern of reverse causation exists about the association between nasopharyngeal carcinoma (NPC) prognosis and body mass index (BMI) at diagnosis, while the prognostic impact of BMI measured years before diagnosis is unknown. Therefore, we investigated associations of prediagnosis and pretreatment BMI and body shape on NPC mortality. From a population-based patient cohort in southern China between 2010 and 2013, we included 2526 incident NPC cases with prospective follow-up through 2018. We assessed the associations of BMI and body shape at age 20 years, 10 years before diagnosis, and at diagnosis with NPC mortality, combining strategies of stratification and statistical adjustment to minimize reverse causation. We observed 25% lower all-cause mortality (hazard ratio [HR] 0.75, 95% confidence interval [CI]: 0.64-0.89) and 25% lower NPC-specific mortality (HR 0.75, 95% CI: 0.61-0.91) among overweight vs normal-weight NPC cases at diagnosis. Lean body shapes 1 and 2 at diagnosis were associated with 68% and 23% higher all-cause mortality, respectively, compared to normal body shape 3. No effect modification by cancer stage was detected for associations with all-cause or NPC-specific mortality. Associations with BMI and body shape 10 years before diagnosis were similar but attenuated, while body size and shape at age 20 were not associated with mortality. Being overweight at diagnosis decreased mortality, and thinner body shape increased mortality, compared to normal weight/body shape. These associations may be due to poorer nutrition and treatment intolerance, resulting in treatment discontinuation and worse survival outcomes.
鼻咽癌（NPC）预后与诊断时体重指数（BMI）之间的关联存在反向因果关系问题，而诊断前数年测量的BMI对预后的影响尚不清楚。因此，我们研究了诊断前和治疗前BMI及体型与NPC死亡率之间的关联。从2010年至2013年中国南方一个基于人群的患者队列中，我们纳入了2526例新发NPC病例，并对其进行前瞻性随访至2018年。我们评估了20岁（诊断前10年）、诊断时的BMI和体型与NPC死亡率之间的关联，采用分层和统计调整策略以尽量减少反向因果关系。我们观察到，诊断时超重的NPC病例与正常体重的病例相比，全因死亡率降低25%（风险比[HR]0.75，95%置信区间[CI]：0.64 - 0.89），NPC特异性死亡率降低25%（HR 0.75，95%CI：0.61 - 0.91）。与正常体型3相比，诊断时的瘦体型1和2分别与全因死亡率高68%和23%相关。未检测到癌症分期对全因或NPC特异性死亡率关联的效应修饰。诊断前10年的BMI和体型的关联相似但减弱，而20岁时的体型和大小与死亡率无关。与正常体重/体型相比，诊断时超重可降低死亡率，体型较瘦则增加死亡率。这些关联可能是由于营养较差和治疗耐受性差，导致治疗中断和生存结果更差。
