title: Type 2 diabetes mellitus and risk of oral cancer and precancerous lesions: a meta-analysis of observational studies.
abstract: OBJECTIVE
  Associations between type 2 diabetes mellitus (type 2 DM) and risk of oral cancer and precancerous lesions have been reported with controversial findings. We performed a meta-analysis to explore these associations.
  
  
  METHODS
  We identified studies by a literature search of MEDLINE and EMBASE through May 31, 2014, and by searching the reference lists of pertinent articles. Summary relative risk (SRR) with 95% confidence interval (CI) was calculated with a random-effects model. Between- study heterogeneity was assessed using the Cochran's Q and I(2) statistics.
  
  
  RESULTS
  A total of 13 studies (4 case-control and 9 cohort studies) on the association between type 2 DM and oral cancer were included. Overall analysis found that compared with non-diabetic individuals, individuals with type 2 DM had a significantly elevated incidence of oral cancer (SRR=1.15, 95% CI: 1.02-1.29; Pheterogeneity=0.277, I(2)=15.4%; 10 studies). Subgroup analyses found that duration of follow-up (⩾11years) significantly altered this positive association. Type 2 DM was associated with increased oral cancer mortality (SRR=1.41, 95% CI: 1.16-1.72; 4 studies). Meta-analysis of the four case-control studies showed a positive association between type 2 DM and risk of oral precancerous lesions (SRR=1.85, 95%CI: 1.23-2.80; Pheterogeneity=0.038, I(2)=57.5%). No significant public bias was found across these studies.
  
  
  CONCLUSIONS
  These findings of this meta-analysis indicate that compared with non-diabetic individuals, individuals with type 2 DM have an elevated risk of oral cancer and precancerous lesions development.
authors: Department of Stomatology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors: Yuhua
authors: Y
authors: Gong
authors: Department of Stomatology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors: Benjuan
authors: B
authors: Wei
authors: Department of Stomatology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors: Li
authors: L
authors: Yu
authors: Department of Stomatology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China. Electronic address: weijpan@126.com.
authors: Weijuan
authors: W
authors: Pan
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D006801:Humans; D009062:Mouth Neoplasms / Q000150:complications*; D011230:Precancerous Conditions / Q000150:complications*; D012307:Risk Factors
keywords: Meta-analysis; Oral cancer; Precancerous lesions; Type 2 diabetes mellitus