Tooth Loss and the Incidence of Ischemic Stroke and Transient Ischemic Attack: A Systematic Review and Meta-Analysis

Generally, as the population is aging, ischemic stroke is imposing rising social and economic burdens. On that basis, the early intervention and prevention of ischemic stroke turns out to be a major public health issue. Extensive studies have reached mixed conclusions regarding the correlation between tooth loss and ischemic stroke, as well as transient ischemic attack (TIA). In this paper, a systematic review and meta-analysis is presented where we have aimed to examine whether tooth loss is correlated with a higher incidence of ischemic stroke and TIA in adults. The systematical search was conducted in PubMed, Web of Science, Embase, and The Cochrane library from the inception dates to September 23, 2021, by employing the keywords (i.e., tooth loss and ischemic stroke). Observational studies conducted in adults were included, in which people with and without tooth loss (Exposition and Comparison) were observed to determine the incidence of ischemic stroke/TIA (Outcome). The data were extracted, and the study quality was assessed by two reviewers independently. Moreover, a meta-analysis was conducted to obtain the risk ratios (RRs) and 95% CIs by adopting random-effects models. The major outcome was the incidence of ischemic stroke/TIA in adults with and without tooth loss. On the whole, four cohort studies and three case-control studies were covered, which involved 4,625,514 participants with 33,088 ischemic stroke/TIA cases. In cohort (adjusted RR = 2.58, 95% CI: 2.39-2.79, P < 0.00001, I ² = 31%) and case-control studies (adjusted MD = -4.15, 95% CI: -6.09-(-2.22), P < 0.001, I ² = 77%), a significant correlation was identified between tooth loss and ischemic stroke. The subgroup analyses reported that the results in case-control studies were generally consistent regardless of the selection of controls. This meta-analysis indicated a certain correlation between tooth loss and ischemic stroke.