By Genni Burkhart
In 2017, the National Heart, Lung, and Blood Institute issued a report calling for further research on the microbiome’s role in blood pressure regulation. There's now growing evidence suggesting a possible role, or connection of the gut microbiota in hypertension pathobiology.
Based off of new research published earlier this month in the peer-reviewed Journal of the American Heart Association(JAHA), certain oral bacteria were also associated with the development of hypertension in postmenopausal women.
This study was conducted on more than 1,200 women in the United States with the average participant age being 63 years old. Ten variations of oral bacteria were associated with increased risk of developing high blood pressure (BP), while five strains of the bacteria were linked with lower hypertension risk. The observational study did not prove cause and effect, but researchers did discover possible opportunities to enhance hypertension prevention through targeted oral healthcare.
Clinical Implications of JAHA Study
Hypertension is associated with increased morbidity and health care costs and has become a growing burden carried by many older adults, both male and female. With an aging population, the growth of this issue is expected to continue for decades. That's why, if even a casual association is proven between the oral microbiome and BP regulation, this new insight could offer substantial possibilities for targeted clinical interventions (through oral healthcare) aimed at preventing high BP later in life.
Why Women of a Certain Age?
When systolic and diastolic blood pressure (BP) is defined as: ≥130 or ≥80 mm Hg among US adults aged ≥65 years, hypertension prevalence exceeds 70% and is higher in women than men. Also, the fastest-growing age group is women over the age of 65, with a population projection expected to reach 95 million by the year 2060, where women are expected to outnumber men two to one.
The main goal of this JAHA study was to use "novel prospective data" to discover an association between the oral microbiome and high blood pressure in "older women."
In this study, researchers evaluated the data on 1,215 postmenopausal females, with an average age of 63 years at study enrollment, between 1997 and 2001 from the Buffalo Osteoporosis and Periodontal Disease Study. Upon enrollment, the researchers took 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," says Michael J. LaMonte, Ph.D., M.P.H., a senior author of the study and a research professor in epidemiology at the University at Buffalo State University of New York and a co-investigator in the Women's Health Initiative clinical center. Medication use, as well as medical and lifestyle histories were also taken to determine if a link was present between oral bacteria and hypertension in older women.
Participant BP Upon Enrollment:
- Approximately 35% (or 429 participants) had normal BP readings upon enrollment, with readings below 120/80 mm Hg and no use of BP medications.
- Close to 24% (or 306 participants) had high BP readings, that is over 120/80 mm Hg without medication use.
- 40% (or 480 participants) were reported as having prevalent, diagnosed high BP and were being treated for hypertension with medication.
In the plaque samples taken from participants, researchers discovered 245 unique strains of bacteria. Nearly one-third of the women who didn't present with or weren't being treated for hypertension at the start of the study were later diagnosed with high BP during the follow-up period; an average of 10 years.
Further Analysis Discovered:
- A total of 10 oral bacteria were associated with a 10% to 16% increased risk of developing high BP.
- Five other kinds of oral bacteria were associated with a 9% to 18% lower hypertension risk.
- Even with demographic, lifestyle and medical history factored in these results were consistent. These factors included: advanced age, high cholesterol, nutrition, and smoking – all indicators of increased hypertension.
- When comparing women under 65 to women over 65 and smokers versus nonsmokers, those with "normal versus elevated BP" at the beginning of the study, the potential associations for the same 15 bacteria with hypertension risk among subgroups was analyzed and remained consistent among the comparable groups.
- According to La Monte, "the findings are particularly relevant for postmenopausal women, since the prevalence of high blood pressure is higher among older women than older men."
As quoted on ScienceDaily, Willie Lawrence, M.D., chair of the American Heart Association's National Hypertension Control Initiative's (NHCI) Oversight Committee stated:
"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 Committee. (“UB study finds some oral bacteria linked with hypertension ...”) "Inclusive research on hypertension must continue to be a priority to better understand and address the condition."
It's important to remember this study took an observational approach of previously recorded data, therefore cause and effect cannot be fully concluded with this one study. This approach limited the researchers' ability to identify with absolute validity that certain oral microbiota is related to lower risk of hypertension while others are related to a higher risk. According to lead study author LaMonte, "A randomized trial would provide the evidence necessary to confirm which bacteria were causal agents in developing – or not developing – hypertension over time."
Author: With over 12 years as a published journalist, editor, and writer Genni Burkhart’s career has spanned across politics, healthcare, law, business finance, tech and news. She resides on the western shores of the Puget Sound where she works as the Editor in Chief at DOCS Education out of Seattle, WA.