title: Periodontal disease and risk of head and neck cancer: a meta-analysis of observational studies.
abstract: BACKGROUND
  Many epidemiological studies have found a positive association of periodontal disease (PD) with risk of head and neck cancer (HNC), but the findings are varied or even contradictory. In this work, we performed a meta-analysis to ascertain the relationship between PD and HNC risk.
  
  
  METHODS
  We searched the PubMed, Embase, and Cochrane Library databases for relevant observational studies on the association between PD and HNC risk published up to March 23, 2013. Data from the included studies were extracted and analyzed independently by two authors. Meta-analysis was performed using RevMan 5.2 software.
  
  
  RESULTS
  We obtained seven observational studies involving two cohort and six case-control studies. Random-effects meta-analysis indicated a significant association between PD and HNC risk (odds ratio = 2.63, 95% confidence interval = 1.1.68 - 4.14; p < 0.001), with sensitivity analysis showing that the result was robust. Subgroup analyses based on adjustment for covariates, study design, PD assessment, tumor site, and ethnicity also revealed a significant association.
  
  
  CONCLUSIONS
  Based on currently evidence, PD is probably a significant and independent risk factor of HNC.
authors.affiliation: Department of Stomatology, Taihe Hospital and School of Stomatology, Hubei University of Medicine, Shiyan, Hubei Province, People's Republic of China.
authors.forename: Xian-Tao
authors.initials: XT
authors.lastname: Zeng
authors.forename: Ai-Ping
authors.initials: AP
authors.lastname: Deng
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Xia
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Niu
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Leng
mesh_terms: D006258:Head and Neck Neoplasms / Q000150:complications* / Q000453:epidemiology*; D006801:Humans; D064887:Observational Studies as Topic; D016017:Odds Ratio; D010510:Periodontal Diseases / Q000150:complications* / Q000453:epidemiology*; D012307:Risk Factors; D012680:Sensitivity and Specificity