title: The association between periodontal disease and the risk of myocardial infarction: a pooled analysis of observational studies.
abstract: Several meta-analyses have indicated that periodontal disease (PD) are related to cardiovascular diseases (CVDs). However, the association between PD and myocardial infarction (MI) remains controversial. Here we aimed to assess the association between PD and MI by meta-analysis of observational studies.
  
  
  
  PubMed, EMBASE and the Cochrane Library were searched through July, 2016. Observational studies including cohort, cross-sectional and case-control studies reporting odds ratio (OR) or relative risk (RR) with 95% confidence intervals (CIs) were included in the analysis. Either fixed or random-effects model were applied to evaluate the pooled risk estimates. Sensitivity and subgroup analyses were also carried out to identify the sources of heterogeneity. Publication bias was assessed by the Begg's, Egger's test and funnel plot.
  
  
  
  We included 22 observational studies with 4 cohort, 6 cross-sectional and 12 case-control studies, including 129,630 participants. Patients with PD have increased risk of MI (OR 2.02; 95% CI 1.59-2.57). Substantial heterogeneity in risk estimates was revealed. Subgroup analyses showed that the higher risk of MI in PD patients exists in both cross-sectional studies (OR 1.71; 95% CI 1.07-2.73) and case-control studies (OR 2.93; 95% CI 1.95-4.39), and marginally in cohort studies (OR 1.18; 95% CI 0.98-1.42). Further, subgroup meta-analyses by location, PD exposure, participant number, and study quality showed that PD was significantly associated with elevated risk of MI.
  
  
  
  Our meta-analysis suggested that PD is associated with increased risk of future MI. However, the causative relation between PD and MI remains not established based on the pooled estimates from observational studies and more studies are warranted.
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, 400037, Chongqing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Cardiology, Xinqiao Hospital, Third Military Medical University, 183 Xinqiaozhengjie St., Shapingba District, 400037, Chongqing, China.
authors.forename: Mingbao
authors.initials: M
authors.lastname: Song
authors.affiliation: Department of Stomatology, Southwest Hospital, Third Military Medical University, 400038, Chongqing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Cardiology, Xinqiao Hospital, Third Military Medical University, 183 Xinqiaozhengjie St., Shapingba District, 400037, Chongqing, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Xinqiao Hospital, Third Military Medical University, 183 Xinqiaozhengjie St., Shapingba District, 400037, Chongqing, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Cardiology, Xinqiao Hospital, Third Military Medical University, 183 Xinqiaozhengjie St., Shapingba District, 400037, Chongqing, China. zhexueqin@126.com.
authors.forename: Zhexue
authors.identifier: 0000-0001-7943-1361
authors.initials: Z
authors.lastname: Qin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology*; D064887:Observational Studies as Topic; D016017:Odds Ratio; D010510:Periodontal Diseases / Q000175:diagnosis / Q000453:epidemiology*; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D055815:Young Adult
keywords: Meta-analysis; Myocardial infarction; Observational studies; Periodontal disease