According to a new study published in the peer-reviewed journal American Heart Association, certain oral bacteria were linked to the development of hypertension, often known as high blood pressure, in postmenopausal women.
While earlier research has shown that people with periodontal disease had higher blood pressure than those who do not, the researchers think this is the first prospective study to look at the link between oral bacteria and the development of hypertension.
High blood pressure is commonly defined by two measurements: systolic blood pressure of 130 mm Hg or higher (the upper number showing pressure while the heart beats) and a diastolic blood pressure of 80 mm Hg or higher (the lower number indicating pressure between heartbeats).
“Since periodontal disease and hypertension are especially prevalent in older adults, if a relationship between the oral bacteria and hypertension risk could be established, there may be an opportunity to enhance hypertension prevention through increased, targeted oral care,” said Michael J. LaMonte, PhD, M.P.H., one of the study’s senior authors, a research professor in epidemiology at the University at Buffalo – State University of New York.
At study enrolment, researchers recorded blood pressure and collected oral plaque from below the gum line, “which is where some bacteria keep the gum and tooth structures healthy, and others cause gum and periodontal disease,” LaMonte said.
About 1,215 postmenopausal women (average age of 63 years old at study enrolment, between 1997 and 2001) were evaluated during the research. Researchers also took note of medication usage, medical histories and lifestyle choices to see if there was a relationship between oral bacteria and hypertension in older women.
About 35% (429) of the research participants had normal blood pressure at the time of recruitment, with values below 120/80 mm Hg and no use of blood pressure medication. Nearly a quarter of the individuals (306) had high blood pressure, with values above 120/80 mm Hg and no treatment. About 40% of the individuals (480) were classified as having prevalent treated hypertension, which means they were diagnosed and treated for hypertension with medication.
245 unique strains of bacteria were identified in the plaque samples. About one-third of the women who did not have hypertension or were not being treated at the initial stage of the study were later diagnosed with high blood pressure during the follow-up period, which was an average of 10 years.
The analysis found that 10 bacteria were associated with a 10% to 16% higher risk of developing high blood pressure, and 5 other kinds of bacteria were associated with a 9% to 18% lower hypertension risk.
The researchers looked at the possible correlations between the same 15 bacteria and hypertension risk in other categories, such as women under 65 vs those over 65, smokers versus nonsmokers, those with normal versus raised blood pressure at the start of the trial, and other comparisons. The results were consistent across all the groups that were studied.
“We have come to better appreciate that health is influenced by more than just the traditional risk factors we know to be so important. This paper is a provocative reminder of the need to expand our understanding of additional health factors that may even be influenced by our environments and potentially impact our biology at the endothelial level,” said Willie Lawrence, M.D., chair of the American Heart Association. ”Inclusive research on hypertension must continue to be a priority to better understand and address the condition.”
Because of the observational nature of the study, cause and effect cannot be determined, limiting the researchers’ ability to pinpoint with confidence which bacteria are linked to a reduced risk of hypertension and which are linked to greater risk. According to LaMonte, a randomized study would give the information needed to determine which bacteria were responsible for developing – or not acquiring – hypertension over time.