title: Diabetes mellitus increases the risk of colorectal neoplasia: An updated meta-analysis.
abstract: OBJECTIVE
  Recent studies proved that patients with diabetes were at significantly higher risk of developing colorectal cancer. However, the association between diabetes mellitus and the risk of colorectal adenoma remains undefined. Thus we conducted an updated meta-analysis to identify the association between diabetes mellitus and the risk of colorectal neoplasia including adenoma and cancer.
  
  
  METHODS
  We conducted a search in databases including Pubmed, Web of Science, EMBASE Databases, Cochrane CENTRAL, Wanfang Data, and CNKI database. Case-control and cohort studies were included. All articles were published before January 2015 and the quality of each study was evaluated by the Newcastle-Ottawa Scale. Odds ratios (ORs) or relative risks (RRs) and its corresponding 95% confidence intervals (CIs) for each study were calculated and summary relative risk estimates with corresponding 95% CIs were generated using the random-effects model. Heterogeneity and publication bias were assessed.
  
  
  RESULTS
  Twenty-nine articles including ten case-control studies and nineteen cohort studies were included in this meta-analysis. In a pooled analysis of all studies, diabetes mellitus was associated with increased risk of colorectal neoplasia (RR=1.35, 95% CI=1.28-1.42). The risk increased significantly for both colorectal cancer (RR=1.37, 95% CI=1.30-1.45) and adenoma (RR=1.26, 95% CI=1.11-1.44). Subgroup analyses on study design, gender, geographical region, and type of diabetes mellitus further evidenced these findings.
  
  
  CONCLUSIONS
  Diabetes mellitus was associated with an increased risk of colorectal neoplasia. Not only the increased risk of colorectal cancer but also the higher risk of adenoma was identified in patients with diabetes mellitus.
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Su
authors.initials: S
authors.lastname: Luo
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Jie-Yao
authors.initials: JY
authors.lastname: Li
authors.affiliation: Department of gastroenterology, the First Affiliated Hospital, Guangzhou University of Traditional Chinese Medicine, 510120 Guangzhou, People's Republic of China.
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Zhao
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China. Electronic address: yutao2014@126.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Wa
authors.initials: W
authors.lastname: Zhong
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Zhong-Sheng
authors.initials: ZS
authors.lastname: Xia
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Ti-Dong
authors.initials: TD
authors.lastname: Shan
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ouyang
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China.
authors.forename: Hong-Sheng
authors.initials: HS
authors.lastname: Yang
authors.affiliation: Department of gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107, Yan Jiang Xi Road, 510120 Guangzhou, Guangdong, People's Republic of China. Electronic address: qikuichen@yahoo.com.
authors.forename: Qi-Kui
authors.initials: QK
authors.lastname: Chen
mesh_terms: D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D048909:Diabetes Complications / Q000453:epidemiology*; D006801:Humans; D012307:Risk Factors