The Connection Between Oral and Kidney Health

By Irene Yeh 

Oral diseases have been linked to chronic kidney disease (CKD) due to inflammatory and microbial pathways that go beyond the mouth. Research suggests there is a bidirectional relationship between periodontitis, also known as gum disease, and CKD. Mainly, periodontal inflammation can spread into the bloodstream, raising cytokine levels and damaging blood vessels, which can cause inflammation and accelerate kidney dysfunction. Furthermore, changes to the oral microbiome can allow harmful substances to enter the bloodstream, contributing further to kidney damage. 

Despite this correlation, most evidence comes from observational studies with modest effect sizes. Researchers from the University of Cincinnati College of Medicine reviewed evidence from over 150 published papers, including observational studies, meta-analyses, and international trials to identify growing evidence on the relationship between oral health and kidney health (Springer Nature Link, DOI: https://doi.org/10.1186/s12882-026-04843-y). 

Various Vicious Cycles 

“We know there is an association between chronic kidney disease (CKD) and oral diseases,” said Priyanka Gudsoorkar, the study’s first author and an assistant professor-educator in the Department of Environmental and Public Health Sciences at the University of Cincinnati College of Medicine, in a press release. “The emerging evidence supports a bidirectional relationship.” 

The team found that gum disease inflammation and CKD are connected through a bidirectional network of immune, vascular, metabolic, and microbial pathways that mutually reinforce disease progression. In the mouth, when plaque builds up around teeth, the microbiome balance becomes disrupted, triggering the immune system to react and releasing inflammatory signals. If this inflammation is long-term, bacteria and inflammatory molecules enter the bloodstream and spread inflammation through the body. Over time, blood vessels get damaged, increasing oxidative stress, and potentially contributing to kidney issues. 

CKD also disrupts the immune system by building up toxins, weakening immune cells’ ability to fight infections and keeping the body in a constant low-level inflammatory state. This makes it more difficult to control the mouth microbiome and further contributes to inflammation. As a result, periodontitis can progress more quickly, and a vicious cycle occurs.  

It isn’t just the mouth and kidneys that affect each other, though. Chronic inflammation with ongoing immune activity can lead to the breakdown of bone around the teeth and the degradation of supporting tissues. When the lining of periodontal pocket becomes damaged, bacteria and inflammatory molecules can enter the bloodstream. Inflammation can even reach the bone marrow, where immune cell production becomes altered, leading to the release of overly reactive cells that perpetuate inflammation throughout the body. In the kidneys, the heightened immune activity makes the tissue more vulnerable to damage by increasing immune cell buildup, inflammation, and oxidative injury, thus speeding up the progression of CKD. 

Furthermore, CKD worsens mineral and bone balance while also contributing to the hardening of blood vessels and weakening bones. Damaged blood cells reduce healthy blood flow to the gums and kidneys, causing low oxygen levels, increased inflammation, and ongoing tissue damage. Evidence also shows that imbalances in minerals (e.g. calcium and phosphate) and parathyroid hormone levels are often linked to gum and oral tissue damage. 

In advanced gum disease, neutrophils—key immune cells—don’t function normally. They live longer than they should, produce excessive harmful molecules, and don’t move efficiently to where they’re needed. Instead of protecting tissue, these changes can cause more damage and even trigger immune-related problems. In the kidneys, overactive neutrophils and their byproducts can damage blood vessels, injure filtering structures, and promote inflammation in surrounding tissue.  

Imbalance in bacteria and metabolism adds another layer to the link between gum disease and CKD. In gum disease, the harmful bacteria can interfere with immune defenses, and in CKD, toxin build-up and other bodily changes can disrupt the microbiome balance in the gut and mouth, weaken protective barriers, and alter how bacteria function. These changes can allow the bacteria to spread through the bloodstream and keep the body in a state of metabolic stress and inflammation, further damaging the kidneys and gums. 

Integrated Care is Needed 

According to Gudsoorkar’s statement in the press release, there needs to be “a framework that supports oral and renal care integration across the CKD continuum.” 

The research team writes that non-surgical periodontal therapy (NSPT) has been shown to lower systemic inflammation for patients with CKD, as well as yield small improvements in kidney function and nutritional status for patients in end-stage kidney disease. Although it remains unclear whether these benefits can lead to long-term improvements for kidney outcomes, these findings suggest that NSPT can at least partially reverse the inflammation in CKD.  

Conversely, treating CKD may influence periodontal inflammation and disease trajectory through improvements in immune competence, metabolic homeostasis, and vascular health. However, the data on these findings is quite sparse. The removal of toxins through intensified or adequate dialysis can lower inflammation and oxidative stress, as well as improve immune cell function. These changes may partially restore antimicrobial defense in the gums and reduce gum inflammation. Additionally, treating CKD-related anemia and metabolic acidosis can improve oxygen levels in tissues and balance local pH levels, limiting inflammation and gum tissue breakdown. 

Some observational studies in dialysis and kidney transplant patients suggest that improved renal function or toxin control is linked to stable or slightly better periodontal health, but the results vary, especially in transplant patients on immunosuppressive therapy. Additionally, more oral complications may appear after dialysis begins, such as gum overgrowth, small bleeding spots, and weakened jawbones. The team writes that dental care needs to be carefully timed around dialysis sessions and adjusted to account for blood-thinning medications. Incidentally, other conditions that cause CKD, such as diabetes, can independently worsen gum disease.  

But What’s Stopping Integrated Care? 

CKD is predicted to be a top cause of years of live lost by 2040 and projected to cost the U.S. $130 billion in Medicare. On a global scale, approximately 80% of affected individuals live in low- and middle-income countries, where late diagnosis, under-sourced health systems, and limited preventive strategies accelerate disease progression. Women also experience higher rates of untreated dental decay and delayed CKD diagnosis. Yet integrated care, while emerging, remains fragmented across regions. 

Cultural perceptions of oral health being more cosmetic than medical may impede integration and continue to be restrained by limited community-health literacy. Even the World Health Organization lacks indicators that link oral inflammation with kidney or cardiovascular issues. There are still no clear, standardized guidelines for dental care, especially for patients waiting for a kidney transplant. Surveys show that there are broad differences in how dental screenings are done before transplantation, how infections are managed, and whether preventive antibiotics are used.  

Fortunately, there are some countries that have frameworks that connect nephrology and dental services. For example, in Japan, routine oral evaluations are a part of dialysis treatment. Brazil also has a preventative outreach program for high-risk populations that integrates oral and chronic disease management.  

How to Progress Integrated Treatment 

To progress integrated treatment for oral and kidney health, the research team provided a few methods. Electronic health records (EHRs) can play a crucial role in embedding oral assessments into CKD workflows. EHRs and machine learning algorithms can identify oral frailty as an early indicator of kidney function decline. 

Interprofessional education is also the foundation of sustainable integration. The research team writes that curricula that combine nephrology, dental hygiene, and public health competences improve student self-efficacy and collaborative readiness. They also encourage integrated residency or fellowship programs linking oral medicine and nephrology to improve patient continuity and safety.  

Research also shows that patients with CKD have unique patterns of oral bacteria. This opens the opportunity of using saliva tests to help diagnose and monitor diseases through specific biomarkers and predictive tools. Concurrently, genomics and bioinformatics have identified shared inflammatory pathways between gum disease, kidney diseases, and cardiovascular conditions, reinforcing the need for personalized treatment and targeted therapy. 

Community-based programs and telehealth models demonstrate lower overall inflammation and improve patient outcomes by supporting coordinated care between oral health and kidney care providers. These informatics-driven, interdisciplinary innovations underscore the feasibility and clinical value of integrating oral health into routine nephrology practice is both practical and beneficial, particularly for vulnerable and underserved populations. 

The team urges for more research to understand how gum inflammation, changes in oral microbiome, and immune system activation are biologically linked to kidney-related outcomes, such as transplant rejection, protein in urine, and cardiovascular complications. This type of research will provide the foundation for clear clinical guidelines and more personalized ways to assess risk in people with CKD. The research team also encourages studying real-world barriers to facilitate adaptation and broader implementation of integrated care models. Improving electronic medical record interoperability could streamline monitoring oral-systemic risk factors, automate dental referrals, and enhance shared care planning between nephrology and dental professionals.  

More long-term studies and well-designed trials are needed to determine whether periodontal treatment directly improves kidney health and how effective the benefits are. Future research should also focus on how to apply existing knowledge in real-world settings so that effective strategies can be put into practice, improve patient outcomes, and advance equitable, holistic care.