Periodontitis and metabolic diseases (diabetes and obesity): Tackling multimorbidity.

Noncommunicable diseases (NCDs) are multifactorial, long-term, chronic conditions that represent a burden to health-care systems worldwide as they can only be controlled rather than cured; hence, they require long-term care. With the exponential increase in NCDs, the occurrence of individuals presenting with more than one chronic disease is also rapidly rising. "Multimorbidity," defined as the presence of two or more long-term physical or mental disorders, is now considered a worldwide epidemic, affecting around 20% of the adult population. Periodontitis, diabetes, and obesity, all chronic inflammatory diseases, are an example of multimorbidity highly relevant to dental practitioners. Over the last three decades, the three-way relationship among the diseases has been vastly researched and accepted, with important contributions by European researchers. The interplay among periodontitis, diabetes, and obesity is sustained by shared biological mechanisms, such as systemic inflammation, insulin resistance, and metabolic dysfunction, as well as common lifestyle-related risk factors. As such, unhealthy lifestyles were found to generally increase systemic inflammation and insulin resistance and decrease immune function, hence, eventually increasing the risk of NCDs onset and the development of multimorbidity. This narrative review of the evidence supports the need for a paradigm shift from a "single-disease" to a "multiple-disease" framework, characterized by an integrated multidisciplinary approach, which should include lifestyle modification interventions to successfully tackle multimorbid periodontitis and metabolic diseases (diabetes and obesity). A multidisciplinary integrated care pathway in both dental and medical settings should be considered to further tackle the global health challenge of multimorbidity.