Institute for Medical Information Processing, Biometry and Epidemiology - IBE, LMU Munich, Munich, Germany.
Pettenkofer School of Public Health, Munich, Germany.
BMC Cancer. 2022 May 14;22(1):546. doi: 10.1186/s12885-022-09589-y.
Body mass index (BMI) and cardiometabolic comorbidities such as cardiovascular disease and type 2 diabetes have been studied as negative prognostic factors in cancer survival, but possible dependencies in the mechanisms underlying these associations remain largely unexplored. We analysed these associations in colorectal and breast cancer patients.
Based on repeated BMI assessments of cancer-free participants from four European countries in the European Prospective Investigation into Cancer and nutrition (EPIC) study, individual BMI-trajectories reflecting predicted mean BMI between ages 20 to 50 years were estimated using a growth curve model. Participants with incident colorectal or breast cancer after the age of 50 years were included in the survival analysis to study the prognostic effect of mean BMI and cardiometabolic diseases (CMD) prior to cancer. CMD were defined as one or more chronic conditions among stroke, myocardial infarction, and type 2 diabetes. Hazard ratios (HRs) and confidence intervals (CIs) of mean BMI and CMD were derived using multivariable-adjusted Cox proportional hazard regression for mean BMI and CMD separately and both exposures combined, in subgroups of localised and advanced disease.
In the total cohort of 159,045 participants, there were 1,045 and 1,620 eligible patients of colorectal and breast cancer. In colorectal cancer patients, a higher BMI (by 1 kg/m2) was associated with a 6% increase in risk of death (95% CI of HR: 1.02-1.10). The HR for CMD was 1.25 (95% CI: 0.97-1.61). The associations for both exposures were stronger in patients with localised colorectal cancer. In breast cancer patients, a higher BMI was associated with a 4% increase in risk of death (95% CI: 1.00-1.08). CMDs were associated with a 46% increase in risk of death (95% CI: 1.01-2.09). The estimates and CIs for BMI remained similar after adjustment for CMD and vice versa.
Our results suggest that cumulative exposure to higher BMI during early to mid-adulthood was associated with poorer survival in patients with breast and colorectal cancer, independent of CMD prior to cancer diagnosis. The association between a CMD diagnosis prior to cancer and survival in patients with breast and colorectal cancer was independent of BMI.
体重指数（BMI）和心血管疾病和 2 型糖尿病等心血管合并症已被研究为癌症生存的负面预后因素，但这些关联背后的机制依赖性在很大程度上仍未得到探索。我们分析了结直肠癌和乳腺癌患者的这些关联。
基于欧洲癌症与营养前瞻性调查（EPIC）研究中来自四个欧洲国家的癌症无患者的反复 BMI 评估，使用生长曲线模型估计反映 20 至 50 岁之间预测平均 BMI 的个体 BMI 轨迹。在 50 岁后患有结直肠癌或乳腺癌的患者被纳入生存分析，以研究癌症前平均 BMI 和心血管代谢疾病（CMD）的预后作用。CMD 定义为中风、心肌梗死和 2 型糖尿病之一或多种慢性疾病。使用多变量调整 Cox 比例风险回归分别为平均 BMI 和 CMD 以及两者联合暴露，在局部和晚期疾病亚组中得出平均 BMI 和 CMD 的危险比（HR）和置信区间（CI）。
在 159045 名参与者的总队列中，有 1045 名和 1620 名符合条件的结直肠癌和乳腺癌患者。在结直肠癌患者中，BMI 每增加 1kg/m2，死亡风险增加 6%（HR 的 95%CI：1.02-1.10）。CMD 的 HR 为 1.25（95%CI：0.97-1.61）。在局部结直肠癌患者中，这两种暴露的关联更强。在乳腺癌患者中，BMI 每增加 1kg/m2，死亡风险增加 4%（95%CI：1.00-1.08）。CMD 与死亡风险增加 46%相关（95%CI：1.01-2.09）。调整 CMD 后，BMI 的估计值和 CI 仍然相似，反之亦然。
我们的研究结果表明，成年早期至中期累积暴露于较高 BMI 与乳腺癌和结直肠癌患者的生存较差相关，与癌症诊断前的 CMD 无关。癌症前 CMD 诊断与乳腺癌和结直肠癌患者的生存之间的关联独立于 BMI。
