Having uncontrolled high blood pressure (or hypertension, as it's medically known) can cause heart attack, stroke, aneurysm, heart failure, kidney problems, and more. Less well known is the fact that high blood pressure can also lead to dementia—a particularly troubling fact given that data shows 71.6 percent of U.S. adults over age 60 have hypertension. Of that group, it's estimated that only 29.2 percent have their high blood pressure controlled.
However, a new study suggests that "intensive" blood pressure reduction can effectively lower the risk of dementia among those with uncontrolled hypertension.
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High blood pressure could lead to dementia.
You may know the numbers you want to see on a blood pressure reading, but do you know what they actually mean?
The top number is systolic blood pressure, "the pressure in your arteries when your heart is beating and sending blood into your arteries," notes Cleveland Clinic. The bottom number is diastolic blood pressure, "the pressure in your arteries when your heart is at rest between heartbeats."
When your blood pressure is high, the force of the blood pushing against your artery walls is elevated, making it harder for the heart to pump blood. So, how does this affect the brain?
As Mayo Clinic explains, "Narrowed or blocked arteries can limit blood flow to the brain. This can cause a certain type of dementia called vascular dementia. A stroke that interrupts blood flow to the brain also can cause vascular dementia."
Moreover, a study published in the Journal of Alzheimer’s Disease found that stroke (a possible side effect of uncontrolled high blood pressure) doubles the risk for dementia, with 30 percent of patients experiencing cognitive dysfunction within three years of the stroke.
Hypertension is also a risk factor for developing type 2 diabetes, and as Best Lifepreviously explained, consistently low blood sugar levels can damage the parts of the brain responsible for memory.
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But scientists say this dementia risk can be lowered.
The new study, published this week in the journal Nature, enlisted roughly 34,000 participants in rural China, all of whom were 40 or older and had uncontrolled hypertension.
Half of the participants were given "intensive blood pressure management," which included "free or cheap medications to lower blood pressure, given at tailored doses, health coaching to help them stick to medications and lifestyle modifications—such as weight loss, alcohol reduction and reducing salt intake—and equipment and instructions to monitor blood pressure at home," reports The Guardian.
The other half received "usual care," which was less individualized and did not include free medications or coaching.
At the end of the four-year study period, the researchers concluded that those in the "intensive" group had a 15 percent lower risk of dementia and a 16 percent lower risk of cognitive impairment without dementia.
"Given the high prevalence of uncontrolled hypertension worldwide, this effective intervention should be widely adopted and scaled up to reduce the global burden of dementia," Jiang He, MD, co-author of the study and a professor at the University of Texas Southwestern Medical Center, told The Guardian.
However, scientists not involved in the study note that the lifestyle changes made by the intensive group could also play a role, in addition to blood pressure on its own. Therefore, they believe a longer follow-up period could provide more concrete results.
"It will be important to see whether this reduced risk continues for longer than the four-year follow-up period in the study, and whether similar effects are seen in other populations that receive the same treatment," said James Leiper, director of research at the British Heart Foundation, in speaking with The Times. "If so, wider use of high blood pressure treatment in people with the condition could be recommended to fight the growing impact of dementia."
