The relationship between periodontal disease and age-related disease

Our objectives of this narrative review is to summarize the scientific perspective on the effect of periodontal disease on age-related diseases, focusing on chronic low-level systemic inflammation, and discuss the goals for future research. In this review, we summarized the findings of articles that showed the mechanisms of periodontal disease and each age-related disease. Periodontal disease is a prevalent infectious disease due to oral anaerobic bacteria that results in dissolution of the gums around the teeth (gingiva) and the bone supporting the teeth, leading to decreased quality of life. The disease is more prevalent with increasing age and associated with age-related diseases, such as diabetes, non-alcoholic fatty liver disease, cardiovascular disease, dementia, and osteoporosis via chronic low-level systemic inflammation, which requires long-term care and increases medical costs. Chronic low-level systemic inflammation due to periodontal disease is a common risk factor for age-related diseases, but the mechanisms of inflammation in each disease vary. Periodontal pathogens mainly cause three patterns of inflammation: cytokine crosstalk that attacks the whole body, changes in the balance of gut microbiota, and production of proteases like gingipains that can subvert immune responses to reach various systemic organs, especially the brain. Several age-related diseases, such as diabetes and dementia, can be improved by treating periodontal disease as inflammatory markers are reduced. In conclusion, it will be necessary to confirm whether the exact mechanism in the human body is the same as that in mice. Improvement in chronic low-level systemic inflammation caused by periodontal disease may be effective in the treatment of age-related diseases.