We know that gum disease is linked to a wide range of health problems. For years, we have tried to determine whether there was a link between gum disease and Alzheimer’s disease or other forms of dementia. Now a new study seems to put the question to rest: gum disease is associated with a significant increase in Alzheimer’s disease risk.
Using data from the National Health and Nutrition Examination Survey (NHANES), researchers determined that having gum disease was likely linked to a more than 20% increase in the risk of developing Alzheimer’s disease and a nearly 50% increase in the risk of dying from Alzheimer’s disease. Although this risk isn’t as large as some studies have shown, this large, current study confirms the link between the conditions.
Questions still remain about how gum disease leads to Alzheimer’s disease, but this new analysis shows a strong connection.
For the new study, researchers used NHANES data to track the possible connection between gum disease and Alzheimer’s disease. The team looked at different age groups at baseline and multiple follow-ups. In some cases, researchers obtained follow-up data for up to 26 years for some patients.
The study team looked at dental exam results for the NHANES patients. Researchers also used blood samples from participants to check for antibodies against 19 oral bacteria. They found that elevated levels of Porphyromonas gingivalis were associated with both an elevated level of Alzheimer’s disease incidence and death from Alzheimer’s disease.
However, the study only looked at the correlation between the two conditions. It didn’t attempt to explain how gum disease might cause Alzheimer’s disease. For that, we have to look at multiple earlier studies.
One of the most straightforward possible explanations why gum disease causes Alzheimer’s disease is inflammation. Inflammation is a complex immune response to injury, but most people associate it with the swelling they experience after an injury or when they have an infection.
We know that brain inflammation likely plays an important role in the progression of Alzheimer’s disease.
As a chronic inflammation, gum disease could potentially trigger this inflammation, assuming it had some way of reaching the brain. The body attempts to isolate the brain from the rest of the body in part to prevent infection, but it’s not always effective.
In a recent review of over 200 studies looking at the possible connection between Alzheimer’s disease and oral bacteria, scientists break down the possible methods by which oral bacteria can reach the brain.
The most likely pathway, they say, is via the bloodstream. Since bacteria enter our bloodstream several times a day, causing bacteremia–blood infections that can last for hours. How do bacteria get past the blood-brain barrier, structures to keep microorganisms out of the brain? However, studies have shown that distributed infections of oral microorganisms, including the normally harmless Candida fungi, can break down the blood-brain barrier. This allows bacteria to enter the brain.
Another possible pathway is via the circumventricular organs. These are various glands and sensory organs that connect to the brain but don’t have the normal blood-brain barrier. Basically, these organs allow bacteria to simply go around the blood-brain barrier.
Perivascular spaces could also allow bacteria to enter the brain. These spaces around blood vessels contain fluids that could allow bacteria to go around the blood-brain barrier.
Finally, it’s possible that bacteria could travel directly on nerves that link to the brain. Previous research identified the trigeminal nerve and the olfactory nerve as pathways oral bacteria use to go toward the brain.
One of the important dangers of gum disease bacteria is their ability to manipulate the immune system. This ability is what links gum disease to autoimmune disorders (like rheumatoid arthritis). Research suggests that this might be in part what links gum disease and Alzheimer’s disease.
In this theory, once oral bacteria have penetrated the brain, they affect the way the immune system works, triggering a runaway inflammatory response, while at the same time making it hard for the brain to clear away damaging waste products. The products build up in the brain and form the amyloid-beta films that are common in Alzheimer’s patients.
Researchers have not definitively linked gum disease to Alzheimer’s disease, but this new correlation provides strong evidence. In addition, research shows that oral bacteria have many easy routes to the brain, that they can cause inflammation, and that inflammation of the brain is a key component of Alzheimer’s disease. They recommend that treatment of gum disease could help prevent Alzheimer’s disease. Early intervention is necessary to avoid cumulative damage. It can also help prevent your need for gum graft surgery.
If you are looking for gum disease treatment or preventive dentistry in Beverly Hills, please call for an appointment with a periodontist at Ravon Knopf.