How poor oral health may increase dementia risk

Research linking oral health to general illnesses, including Alzheimer’s disease, is rapidly expanding. As populations age, the global number of Alzheimer’s cases is expected to rise at an alarming rate, placing immense pressure on health-care systems, families, and caregivers all over the world. This highlights the urgent need to focus on preventive measures, such as improving oral health especially among older populations.

In the US, Alzheimer’s disease currently affects nearly 7 million people, a number expected to almost double by 2050, according to the Alzheimer’s Foundation of America. Alzheimer’s makes up 60%–80% of dementia cases, primarily affecting older adults, though younger-onset Alzheimer’s also occurs in people under age 65.¹

With no cure yet available, the focus in managing Alzheimer’s disease remains on controlling symptoms and slowing its progression. However, there is reason for optimism. In 2023, clinical trials in the US investigated more than 140 potential treatments aimed at slowing Alzheimer’s progression, with approximately 80% focusing on slowing the course of the disease.²

Oral health has emerged as an important, though often overlooked, factor in Alzheimer’s risk, medical experts say. Interest in the connection between oral health and Alzheimer’s disease is growing, with many medical professionals highlighting the need for improved oral hygiene to help combat common oral health issues, including gingivitis and more severe gum disease, periodontitis. While there is no definitive proof that maintaining good oral hygiene can prevent Alzheimer’s, many experts believe it is a crucial area of preventive care.

Professor emeritus Dr. Jukka Meurman, from the University of Helsinki, Finland, stresses, “Oral infections represent a statistical risk for Alzheimer’s, just as they do for diseases such as diabetes and cardiovascular conditions. Therefore, the importance of preventive oral care cannot be overstated.”

Why early diagnosis matters

Identifying Alzheimer’s early is critical for better symptom management and future treatment planning. Early signs include memory problems, confusion, difficulty with daily tasks, and mood changes. Timely diagnosis allows for early intervention and treatment.

Several biological mechanisms explain the connection between oral health and Alzheimer’s. Studies show that periodontitis, a severe gum disease, is a significant risk factor for cognitive decline.³

“Gingipains—enzymes produced by the oral bacteria Porphyromonas gingivalis—have been found in the brain tissue of Alzheimer’s patients. Gingipains are neurotoxic, meaning they can damage brain cells,” Dr. Meurman explains.

Chronic inflammation caused by conditions such as periodontitis may also affect brain health and accelerate the progression of Alzheimer’s, Dr. Meurman says. Studies show that the disease is characterized by beta-amyloid plaques in the brain, which may be linked to the immune response to pathogens, including those from oral infections.³

“Periodontitis causes persistent inflammation in the mouth, which can spread throughout the body. This chronic low-grade inflammation has been associated with various diseases, including Alzheimer’s. It may exacerbate neuroinflammatory responses in the brain, leading to the destruction of neurons and cognitive decline.”

Periodontitis: A risk factor for multiple diseases

Dr. Meurman emphasizes the importance of quickly treating oral infections, as bacteria entering the bloodstream can cause infections elsewhere. Poor oral health is linked to various health problems, not just cognitive disorders. Studies indicate that oral infections contribute to physical illnesses, including metabolic syndrome, heart disease, and depression, and can even lead to premature death.⁴

Research published in the Journal of the American Geriatrics Society highlights that severe gum disease increases the risk of dementia by around 20%, especially in individuals with advanced periodontitis or significant tooth loss.⁵

Given the strong connection between oral and systemic diseases, health-care policies should prioritize oral hygiene as a preventive measure, Dr. Meurman says. “This could be achieved by raising awareness of the link between oral and general health and developing programs that support better oral hygiene on a population level.”

This is especially important as health and long-term care costs for dementia are projected to reach $360 billion in 2024 and nearly $1 trillion by 2050, according to the Alzheimer’s Association.

Dr. Meurman notes, “Preventive strategies can help mitigate this growing financial and societal burden.”

A two-way relationship

Cognitive decline and poor oral health are closely linked in a two-way relationship. As dementia progresses, patients often struggle to maintain proper oral hygiene, which can worsen conditions such as periodontitis. This, in turn, contributes to increased inflammation that may negatively impact brain health. Thus, caregivers and family members play a vital role in assisting elderly or cognitively impaired individuals with daily oral care.⁶

Proper oral care throughout life is vital for preserving oral and brain health. While more research is needed to confirm how oral infections influence Alzheimer’s, maintaining good oral hygiene can enhance overall health and may help reduce dementia risk in the long run.