Gum disease has been linked to several health conditions including diabetes and cardiovascular illnesses, as well as chronic inflammation throughout the body. Japanese researchers have uncovered yet another concerning condition related to gum problems — brain shrinkage in the hippocampus, the area of our brain which plays a major role in memory and Alzheimer’s disease.

It’s not unusual to have gum disease. Nearly half of all adults aged 30 years or older show signs of the condition — and severe gum disease affects 9 percent of adults, according to the Centers for Disease Control (CDC).

You now have another reason to take better care of your teeth.

“Tooth loss and gum disease, which is inflammation of the tissue around the teeth that can cause shrinkage of the gums and loosening of the teeth, are very common, so evaluating a potential link with dementia is incredibly important,” study author, Satoshi Yamaguchi, of the Division of Aging and Geriatric Dentistry, Tohoku University, Japan, said in a press statement. “Our study found that these conditions may play a role in the health of the brain area that controls thinking and memory, giving people another reason to take better care of their teeth.”

The study involved 172 people with an average age of sixty-seven. The participants had dental exams and took memory tests at the beginning of the study. None had memory problems at the time. They also had brain scans to measure the volume of their hippocampus at the start of the study and again four years later.

Researchers counted the number of teeth and checked for gum disease by looking at periodontal probing depth, a measurement of the health of gum tissue. Healthy readings range from one to three millimeters. Probing depths of four millimeters in several areas signal mild gum disease; while probing depths of five or six millimeters in several areas indicate severe gum disease and likely loss of bone. Increasing bone loss can cause teeth to become loose and eventually, fall out.

The study revealed an interesting link among three factors: gum disease, tooth count and brain shrinkage in the left hippocampus. In folks with mild gum disease, having fewer teeth was linked to a faster rate of brain shrinkage. In participants with severe gum disease, however, having more teeth was associated with an accelerated rate of brain shrinking in the left hippocampus.

When taking in the age factor, the researchers observed some intriguing trends in brain health:

  • In people with mild gum disease, losing just one tooth was equivalent to aging the brain by almost one year.
  • In folks with severe gum disease, the increase in brain shrinkage was equivalent to aging by about 1.3 years.

“These results highlight the importance of preserving the health of the teeth and not just retaining the teeth,” a researcher added. “The findings suggest that retaining teeth with severe disease is associated with brain atrophy. Controlling the progression of gum disease through regular dental visits is crucial, and teeth with severe gum disease may need to be extracted and replaced with appropriate prosthetic devices.”

The American Dental Association recommends visiting your dentist for a dental exam and cleaning about every six months.

The study is published in the journal, Neurology.