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.
We performed an umbrella review and comprehensively re-analysed 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, oesophagus, 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.
Convincing evidence for an association with BMI was detectable for 5 cancers (leukemia, multiple myeloma, pancreatic, endometrial, rectal, and renal cell carcinoma). Suggestive evidence was detectable for malignant melanoma, non-Hodgkins lymphoma and oesophageal 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.
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-responsive meta-analyses.
Annals of oncology : official journal of the European Society for Medical Oncology. 2017 Dec 28 [Epub ahead of print]
E K Choi, H B Park, K H Lee, J H Park, M Eisenhut, H J van der Vliet, G Kim, J I Shin
Mo-Im Kim Nursing Research Institute, Yonsei University College of Nursing, Seoul, Korea., Department of Pediatrics, Yonsei University College of Medicine, Seoul, Korea Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea., Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea., Children's & Adolescent Services, Luton & Dunstable University Hospital NHS Foundation Trust, Lewsey Road, Luton LU4ODZ, United Kingdom., Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands., Department of Nursing, College of Nursing, Keimyung University, Daegu, Korea.