Aggressively lowering blood pressure could reduce risk of developing dementia, study finds

The medical mantra that “what’s good for the heart is good for the brain” got more support Wednesday.

Aggressively lowering blood pressure in people at high risk for heart attacks and stroke also reduced their likelihood of developing mild cognitive impairment (MCI), a condition that often leads to dementia, a new study found.

“This is the first intervention ever to be shown to reduce the risk of MCI,” said Jeff Williamson, who helped lead the study and who co-directs the Alzheimer's Research Center at Wake Forest University in Winston-Salem, North Carolina.

Patients treated to reduce their systolic blood pressure – the top number in a blood pressure reading – to 120 mm Hg were 19 percent less likely to develop mild cognitive impairment than those whose blood pressure was targeted to 140 mm Hg.

The research was presented Wednesday at the annual Alzheimer's Association International Conference underway in Chicago. The data is considered preliminary because it has not been published or peer reviewed, and Williamson said he saw the last patients as recently as last month.

But he and several other caregivers said they are already enthusiastic about the results.

“This really should have a big impact on how we in healthcare and particularly in family practice and primary care view what the target should be for lowering blood pressure,” said Sharon Cohen, a behavioral neurologist and director of the Toronto Memory Program, Canada’s largest Alzheimer’s research clinic. Cohen, who was not involved in the new study, said “It’s not good enough to aim for 140 systolic. We should be going lower.”

The study tracked 9,300 people, many of whom were over 75 years old, had kidney disease or were otherwise at high risk for cardiovascular problems. They were divided into two groups, one whose systolic blood pressure was targeted for 140 and one for 120. Both groups were counseled to make lifestyle changes to help lower their blood pressure, such as getting regular exercise and adequate sleep, and eating a healthy diet.

The American Heart Association and American College of Cardiology issued new guidelines last year saying that patients should start to be treated at blood pressures of 130/80 rather than the previous standard of 140/90.

In the new study, those targeted to 140 took two medications on average, while those trying to reach 120 were given three. Both were on the medications for an average of three years.

The federally-funded study was more diverse than many previous studies with 30 percent of participants identifying as African-American and 10 percent as Hispanic. The study found no difference in results by race, ethnicity or gender, Williamson said.

Designed initially to look at heart disease, a safety monitoring board decided in 2015 that there was no doubt that lowering blood pressure benefited participants’ hearts – and stopped the study. Patients went back to their regular physicians and some continued the same level of blood pressure control.

The study looked at those participants a few years later to see whether there had been any effect on brain function. In addition to the reduced risk of mild cognitive impairment, MRIs on a group of the participants showed that reducing their blood pressure also lowered their risk of tiny brain bleeds, said Laurie Ryan, chief of the Dementias of Aging Branch of the Division of Neuroscience at the National Institute on Aging, which funded the study along with the National Heart, Lung, and Blood Institute.

The study showed an increase in headaches and dizziness and greater susceptibility to dehydration and mineral imbalances among people with the lower blood pressure target, but no falls or serious incidents.

“I wasn’t sure myself as a scientist, was blood pressure-lowering as good for the brain as it was for the heart? That was a really unanswered question,” Williamson said.

But the data he’s seen so far has been convincing, he said.

“I’ve changed my personal practice,” he said, noting that he makes sure his own blood pressure is well controlled, and in his medical practice, “we talk to individuals about getting their blood pressure in the 120-130 range.”

Harlan Krumholz, a cardiologist and health care researcher at Yale University and Yale-New Haven Hospital in Connecticut, said he sees the study more as the beginning of a conversation, rather than a hard-and-fast blood pressure target. It’s not realistic, he said, to assume every patient will be willing or able to make lifestyle changes and take three daily medications to bring down their blood pressure.

Some patients, he said, take the attitude that “if this thing will help me at all, I’m all in,” while others want more evidence before they’ll agree to more medications.

But the study now provides them another option, he said. In the past, few people would have been offered the possibility of lowering their blood pressure to 120.

“We (need to) really sit down with patients and do the hard work of trying to understand what’s best for them given their preferences,” Krumholz said.

WPXI