Hypertension: Could It Increase Your Risk For Dementia?

High blood pressure(also known as hypertension) translates to the pressure of the blood in one’s blood vessels is higher than it should be. Over 800 million people in the world suffer from hypertension with, according to the American Heart Association, the number being close to 100 million in the United States.

Hypertension can have a number of effects on different parts of the body. It can increase the risk for stroke, heart disease, kidney disease, sexual dysfunction as well as eye blood vessel damage. In regards to cognitive health, a recent study has highlighted the possibility that hypertension can possibly age the brain.

The study

A study from the Rush Alzheimer’s Disease Center at Rush University Medical Center in Chicago, Illinois attempted to find an association between blood pressure and physical markers of brain health in older adults.

“We researched whether blood pressure in later life was associated with signs of brain ageing that include plaques and tangles linked to Alzheimer’s disease,” said Dr. Zoe Arvanitakis, author of the study.

The researchers assessed the blood pressures of almost 1,300 people, following them for an average of 8 years until their deaths(aged 89). Two thirds of the group had a history of hypertension with 87% of taking medication in order to manage it. When high blood pressure is measured, it is assessed in two ways. Firstly, there is the systolic blood pressure which looks at the pressure in the blood vessels as the heart contracts- a healthy reading is 120 mmHg or less. The second measurement is diastolic blood pressure which refers to the pressure in the arteries when the heart is at rest between beats- a healthy reading is 80 mmHg or less. On average, the participants had a blood pressure of 134/72 mmHg (134 systolic over 72 diastolic).

Aside from the blood pressure measurements, researchers also performed autopsies on their brains following their deaths. They did this in order to find infarcts- brain lesions made of dead tissue which can often lead to strokes. Almost half of the participants were found to have at least one infarct in their brains.

The results

The study revealed a link between high blood pressure and and brain health. Specifically, they discovered that with every standard deviation above the group’s
average systolic blood pressure, there was a 46% increased chance of having at least one brain lesion (which is the equivalent of around 9 years of brain aging). Moreover, there was a 46 % increased risk of large lesions and a 36 % increased risk of smaller lesions with each standard deviation increase in systolic blood pressure.

The researchers also noticed a link between declining diastolic blood pressure and an increased risk of lesions.

The verdict

As important as this study is in highlighting the continuous health concerns associated with hypertension, it does have its drawbacks.

Firstly, it only examined the blood pressure readings during the participants' later life as opposed to assessing how their blood pressure changed throughout their lifespan. The blood pressure readings were also only taken once every year and this did very little in offering an accurate picture of how their blood pressure may fluctuate throughout the year.

Moreover, this study was an observational study thus it’s unknown if any of the participants had been diagnosed with Alzheimer’s disease. “While our findings may eventually have important public health implications for blood pressure recommendations for older people, further studies will be needed to confirm and expand on our findings before any such recommendations can be made.” says Dr. Zoe Arvanitakis.

Nonetheless, it’s important to control one’s blood pressure in order to ensure overall health.

You can read more about the study here

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