Type 2 diabetes and cancer: umbrella review of meta-analyses of observational studies
Top Cited Papers
Open Access
- 2 January 2014
- Vol. 350 (jan02 1), g7607
- https://doi.org/10.1136/bmj.g7607
Abstract
Objectives To summarise the evidence and evaluate the validity of the associations between type 2 diabetes and the risk of developing or dying from cancer. Design An umbrella review of the evidence across meta-analyses of observational studies of type 2 diabetes with risk of developing or dying from any cancer. Data sources PubMed, Embase, Cochrane database of systematic reviews, and manual screening of references. Eligibility criteria Meta-analyses or systematic reviews of observational studies in humans that examined the association between type 2 diabetes and risk of developing or dying from cancer. Results Eligible meta-analyses assessed associations between type 2 diabetes and risk of developing cancer in 20 sites and mortality for seven cancer sites. The summary random effects estimates were significant at P=0.05 in 20 meta-analyses (74%); and all reported increased risks of developing cancer for participants with versus without diabetes. Of the 27 meta-analyses, eventually only seven (26%) compiled evidence on more than 1000 cases, had significant summary associations at P≤0.001 for both random and fixed effects calculations, and had neither evidence of small study effects nor evidence for excess significance. Of those, only six (22%) did not have substantial heterogeneity (I2>75%), pertaining to associations between type 2 diabetes and risk of developing breast, cholangiocarcinoma (both intrahepatic and extrahepatic), colorectal, endometrial, and gallbladder cancer. The 95% prediction intervals excluded the null value for four of these associations (breast, intrahepatic cholangiocarcinoma, colorectal, and endometrial cancer). Conclusions Though type 2 diabetes has been extensively studied in relation to risk of developing cancer and cancer mortality and strong claims of significance exist for most of the studied associations, only a minority of these associations have robust supporting evidence without hints of bias.This publication has 62 references indexed in Scilit:
- Risk of bladder cancer in patients with diabetes mellitus: an updated meta-analysis of 36 observational studiesBMC Cancer, 2013
- Diabetes Mellitus, Fasting Glucose, and Risk of Cause-Specific DeathThe New England Journal of Medicine, 2011
- Colorectal Cancer Outcomes, Recurrence, and Complications in Persons With and Without Diabetes Mellitus: A Systematic Review and Meta-AnalysisDigestive Diseases and Sciences, 2009
- Does pre-existing diabetes affect prostate cancer prognosis? A systematic reviewProstate Cancer and Prostatic Diseases, 2009
- Long-term All-Cause Mortality in Cancer Patients With Preexisting Diabetes MellitusJAMA, 2008
- False-Positive Results in Cancer Epidemiology: A Plea for Epistemological ModestyJNCI Journal of the National Cancer Institute, 2008
- Comparison of Two Methods to Detect Publication Bias in Meta-analysisJAMA, 2006
- A modified test for small‐study effects in meta‐analyses of controlled trials with binary endpointsStatistics in Medicine, 2005
- Quantifying heterogeneity in a meta-analysisStatistics in Medicine, 2002
- Meta-analysis in clinical trialsControlled Clinical Trials, 1986