An umbrella review of the evidence linking oral health and systemic health: from the prevalence to clinical and circulating markers

Oral conditions are highly prevalent worldwide. Recent studies have been supporting a potential bidirectional association of oral disorders with systemic noncommunicable diseases (NCDs). Robust evidence supports the greater prevalence of oral conditions in people suffering from NCDs limiting the ability of oral self-care. As for the relationship with other NCDs, the lines of evidence have increased exponentially but not always with the proper coherence. This umbrella review of meta-analyses appraises the strength and validity of the evidence for the association between oral health and systemic health. An extensive search included systematic reviews that have provided meta-analytic estimates on the association of an oral condition with a NCD. The overall strength of evidence was found to be unfavorable and with methodological inconsistencies. Twenty-two NCDs, four types of cancer and circulating levels of CRP were strongly associated with oral diseases. Among the significant NCDs are diabetes mellitus, cardiovascular diseases, depression, neurodegenerative conditions, rheumatic diseases, inflammatory bowel disease, gastric helicobacter pylori, stroke, obesity, diabetes mellitus or asthma. Most evidence is unlikely to change which indicates a relatively robust consistency of the available body of evidence.