title: Periodontal disease and risk of chronic obstructive pulmonary disease: a meta-analysis of observational studies.
abstract: BACKGROUND
  Many epidemiological studies have found a positive association between periodontal disease (PD) and risk of chronic obstructive pulmonary disease (COPD), but this association is varied and even contradictory among studies. We performed a meta-analysis to ascertain the relationship between PD and COPD.
  
  
  METHODS
  PubMed and Embase database were searched up to January 10, 2012, for relevant observational studies on the association between PD and risk of COPD. Data from the studies selected were extracted and analyzed independently by two authors. The meta-analysis was performed using the Comprehensive Meta-Analysis software.
  
  
  RESULTS
  Fourteen observational studies (one nested case-control, eight case-control, and five cross-sectional) involving 3,988 COPD patients were yielded. Based on random-effects meta-analysis, a significant association between PD and COPD was identified (odds ratio = 2.08, 95% confidence interval = 1.48-2.91; P<0.001), with sensitivity analysis showing that the result was robust. Subgroups analyses according to study design, ethnicity, assessment of PD/COPD, and adjusted/unadjusted odds ratios also revealed a significant association. Publication bias was detected.
  
  
  CONCLUSIONS
  Based on current evidence, PD is a significant and independent risk factor of COPD. However, whether a causal relationships exists remains unclear. Morever, we suggest performing randomized controlled trails to explore whether periodontal interventions are beneficial in regulating COPD pathogenesis and progression.
authors.affiliation: Department of Stomatology, Taihe Hospital, Hubei University of Medicne, Shiyan, Hubei Province, People's Republic of China.
authors.forename: Xian-Tao
authors.initials: XT
authors.lastname: Zeng
authors.forename: Ming-Li
authors.initials: ML
authors.lastname: Tu
authors.forename: Dong-Yan
authors.initials: DY
authors.lastname: Liu
authors.forename: Dong
authors.initials: D
authors.lastname: Zheng
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: WeiDong
authors.initials: W
authors.lastname: Leng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D016206:Databases, Bibliographic; D018450:Disease Progression; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010510:Periodontal Diseases / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D017594:Publication Bias; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D012307:Risk Factors; D014481:United States / Q000453:epidemiology