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A recent study investigates links between oral bacteria and high blood pressure. Eugenio Marongiu/Getty Images
  • Almost half of adults in the United States have high blood pressure, or hypertension.
  • People with hypertension have an increased risk of stroke and heart disease.
  • The researchers behind a new study have found a connection between certain types of oral bacteria and the risk of hypertension in people who have experienced menopause.
  • The researchers associate specific bacteria with both baseline blood pressure and the risk of developing hypertension.

The study appears in the Journal of the American Heart Association.

The authors believe there is ground for further research to determine whether this association between oral bacteria and hypertension is causal.

Blood pressure is the pressure of blood pushing against the wall of the arteries. It is normal for blood pressure to rise and fall throughout the day, but if it remains elevated, it can cause health issues.

The Centers for Disease Control and Prevention (CDC) highlight that a person with hypertension is more likely to have a stroke or develop heart disease. An estimated 47% of adults in the U.S. have hypertension, with the condition particularly affecting older adults and females.

Researchers have noted that despite there being evidence-based approaches to preventing and reducing hypertension, it is still highly prevalent. As such, there is continuing research to understand why people develop hypertension and how to address this.

Scientists have identified that the relationship between the microbiome and hypertension risk is worth further investigation.

The microbiome is a collection of microbes — primarily bacteria — that live in and on a person’s body. Scientists are finding more and more evidence that the microbiome plays a role in maintaining good health.

There is some evidence that the gut microbiome affects an individual’s risk of hypertension. In the present study, however, the researchers focused on the oral microbiome and its relationship with hypertension risk.

The researchers drew on the Buffalo Osteoporosis and Periodontal Disease Study. They looked at data from 1,215 women who have experienced menopause, with an average age of 63 when they enrolled in the study between 1997 and 2001.

When the participants enrolled, the researchers took samples of their oral bacteria from below their gumline and measured their blood pressure. The researchers also took the participants’ medical histories and recorded any medications they were taking.

At the beginning of the study, 40% of the participants were taking hypertension medication.

About half of the participants who did not have hypertension or were not receiving treatment for the condition at baseline went on to receive a hypertension diagnosis and treatment during the 10-year average follow-up.

After analyzing the oral bacteria samples, the researchers identified 10 species that they linked to a greater risk of hypertension, ranging from a 10% to a 16% increase.

The researchers also found a link between five bacteria and a 9–18% lower risk of hypertension.

With the exception of two bacteria, these findings held true even when the researchers took into account age and other confounding lifestyle and clinical factors.

Medical News Today spoke with Prof. Michael LaMonte, a research professor in the Department of Epidemiology and Environmental Health at the University at Buffalo, NY.

Prof. LaMonte, corresponding author of the study, said that further research was necessary to understand what might account for the link between specific oral bacteria and increased risk of hypertension in older women.

“The exact mechanisms through which specific oral bacteria might influence blood pressure — for better or for worse — are not entirely clear.”

“We hypothesize that the ability of some oral bacteria to convert dietary nitrate into nitrite which then is further converted in the gut to nitric oxide — a potent chemical responsible for arterial relaxation and dilation — is one likely possibility.”

– Prof. Michael LaMonte

“Also, we know that oral bacteria can escape from the mouth and translocate through the blood circulation to other parts of the body,” Prof. LaMonte explained.

“One such location in which oral bacteria have been found is within the arterial wall encapsulated in atherosclerotic plaques. Atherosclerosis leads to stiffening of arteries, which in turn raises blood pressure. So, it is possible there might be a connection between oral bacteria and arterial atherosclerosis.”

“Of course, there always is the possibility that ours is a chance finding. It will be important to know whether other studies examining this issue find consistent or different results,” said Prof. LaMonte.

MNT also spoke with the American Dental Association (ADA), who also highlighted that the link between specific oral bacteria and hypertension does not necessarily imply causation.

“Just because two things are associated does not mean that one causes the other. This study does not provide updates on whether managing the microorganisms would impact an individual’s risk of developing hypertension.”

“It does suggest, however, that there may be a change in microorganisms in the oral microbiome after a person develops hypertension and is taking prescription medication for blood pressure control.”

To maintain a healthy oral microbiome, the ADA recommended that people:

  • brush their teeth twice per day with a fluoride toothpaste
  • floss daily
  • eat a healthy diet that limits sugary beverages and snacks
  • consult a dentist regularly for prevention and treatment of oral disease

To determine causation, researchers would need to conduct a randomized clinical trial.

According to Prof. LaMonte, “At present, we are not planning a randomized clinical trial to further evaluate this hypothesis, but such a trial will be critical to know whether or not our results reflect causation or merely association.”