Periodontal disease and stroke: a meta-analysis of cohort studies

This review aimed to determine the association between periodontal disease and stroke incidence by a meta-analysis of cohort studies. Cohort studies that evaluated the incidence of stroke (fatal or non-fatal, ischaemic or haemorrhagic) and baseline periodontal status and calculated relative risk values were included. The quality of the included studies was assessed using an evaluation grid. The analyses were conducted separately for three outcomes: periodontitis, gingivitis and loss of teeth. Adjusted values of relative risk or of hazard ratio were used to assess risk values in each study. Random effects meta-analyses were conducted when data could be pooled. From the 743 references retrieved, only nine cohort studies were suitable for inclusion in this review. Quality scores of the studies varied greatly. Three prospective studies, which used reliable indicators of periodontal disease, obtained the highest scores. Conversely, three studies that used a subjective evaluation of stroke incidence or diagnosed stroke without imaging obtained the lowest score. The results of the meta-analyses varied depending on the outcome considered and the type of stroke. The risk of stroke was significantly increased by the presence of periodontitis [relative risk 1.63 (1.25, 2.00)]. Tooth loss was also a risk factor for stroke [relative risk 1.39 (1.13, 1.65)]. The risk of stroke did not vary significantly with the presence of gingivitis. This review shows that periodontitis and tooth loss are associated with the occurrence of stroke.