title: Diabetes mellitus and risk of bladder cancer: a meta-analysis of cohort studies.
abstract: BACKGROUND
  Increasing evidence suggests that diabetes mellitus (DM) may be associated with an increased risk of bladder cancer. To provide a quantitative assessment of this association, we evaluated the relation between DM and incidence and mortality of bladder cancer in an updated meta-analysis of cohort studies. Methods We identified cohort studies by searching the EMBASE and MEDLINE databases, through 31 March 2012. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with random-effects models.
  
  
  RESULTS
  A total of 29 cohort studies (27 articles) were included in this meta-analysis. DM was associated with an increased incidence of bladder cancer (RR 1.29, 95% CI: 1.08-1.54), with significant evidence of heterogeneity among these studies (p<0.001, I(2) = 94.9%). In stratified analysis, the RRs of bladder cancer were 1.36 (1.05-1.77) for diabetic men and 1.28 (0.75-2.19) for diabetic women, respectively. DM was also positively associated with bladder cancer mortality (RR 1.33, 95% CI: 1.14-1.55), with evident heterogeneity between studies (p = 0.002, I(2) = 63.3%). The positive association was observed for both men (RR 1.54, 95% CI: 1.30-1.82) and women (RR 1.50, 95% CI: 1.05-2.14).
  
  
  CONCLUSIONS
  These findings suggest that compared to non-diabetic individuals, diabetic individuals have an increased incidence and mortality of bladder cancer.
authors: Department of Urology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Zhaowei
authors: Z
authors: Zhu
authors: Xiaohua
authors: X
authors: Zhang
authors: Zhoujun
authors: Z
authors: Shen
authors: Shan
authors: S
authors: Zhong
authors: Xianjin
authors: X
authors: Wang
authors: Yingli
authors: Y
authors: Lu
authors: Chen
authors: C
authors: Xu
mesh_terms: D015331:Cohort Studies; D048909:Diabetes Complications / Q000209:etiology* / Q000401:mortality / Q000473:pathology; D003920:Diabetes Mellitus / Q000401:mortality / Q000473:pathology*; D006801:Humans; D012306:Risk; D001749:Urinary Bladder Neoplasms / Q000209:etiology* / Q000401:mortality / Q000473:pathology