Background Objectives were to provide an overview and understand the strength of evidence and extent of potential biases and validity of claimed associations between body mass index (BMI) and risk of developing cancer. Methods We carried out an umbrella review and comprehensively re-analyzed the data of dose-response meta-analyses on associations between BMI and risk of 20 specific cancers (bladder, brain, breast, colonic, rectal, endometrial, gallbladder, gastric, leukemia, liver, lung, melanoma, multiple myeloma, non-Hodgkins lymphoma, esophagus, ovarian, pancreatic, prostate, renal, thyroid) by adding big data or missed individual studies. Convincing evidence for an association was defined as a strong statistical significance in fixed-effects and random-effects meta-analyses at P < 0.001, 95% prediction interval (PI) excluded null, there was no large between-study heterogeneity and no small study effects. Suggestive evidence was defined as meeting the significance threshold for the random summary effects of P < 0.05, but 95% PI included the null. Weak evidence was defined as meeting the significance threshold for the random summary effects at a P < 0.05, but 95% PI included the null and there was large between-study heterogeneity or there were small study effects. Results Convincing evidence for an association with BMI was detectable for six cancers (leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma). Suggestive evidence was detectable for malignant melanoma, non-Hodgkins lymphoma, and esophageal adenocarcinoma. Weak evidence was detectable for brain and central nervous system tumors, breast, colon, gall bladder, lung, liver, ovarian, and thyroid cancer. No evidence was detectable for bladder, gastric, and prostate cancer. Conclusions The association of increased BMI and cancer is heterogeneous across cancer types. Leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma are convincingly associated with an increased BMI by dose-response meta-analyses.

中文翻译：

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体重指数和20种特定癌症：观察研究的剂量反应荟萃分析的重新分析。

背景技术目的是提供概述并了解证据的强度，潜在偏倚的程度以及所声称的体重指数（BMI）与患癌风险之间的关联的有效性。方法我们进行了总括审查，并全面重新分析了BMI与20种特定癌症（膀胱癌，脑癌，乳腺癌，结肠癌，直肠癌，子宫内膜癌，胆囊癌，胃癌，白血病，肝，肺，黑素瘤，多发性骨髓瘤，非霍奇金淋巴瘤，食道，卵巢，胰腺，前列腺，肾，甲状腺），或添加大数据或错过个别研究。有说服力的关联证据被定义为固定效应和随机效应的荟萃分析在P <0.001、95％预测间隔（PI）排除在外时具有很强的统计学意义，研究之间没有很大的异质性，研究效果也很小。提示性证据定义为满足P <0.05的随机汇总效应的显着性阈值，但95％PI包括无效值。弱证据被定义为在P <0.05时满足随机汇总效应的显着性阈值，但是95％的PI包括无效值，并且研究之间的异质性较大，或者研究效应较小。结果在六种癌症（白血病，多发性骨髓瘤，胰腺癌，子宫内膜癌，直肠癌和肾细胞癌）中可检测到与BMI相关的令人信服的证据。对于恶性黑色素瘤，非霍奇金淋巴瘤和食道腺癌，可发现提示性证据。对于脑和中枢神经系统肿瘤，乳腺，结肠，胆囊，肺，肝，卵巢癌和甲状腺癌。没有证据可检测到膀胱癌，胃癌和前列腺癌。结论BMI升高与癌症之间的关联在不同癌症类型之间是异质的。通过剂量反应荟萃分析，白血病，多发性骨髓瘤，胰腺癌，子宫内膜癌，直肠癌和肾细胞癌均与BMI升高有关。