High blood pressure raises the risk of dementia in healthy older adults. In frail ones, however, it may do the opposite.
That’s the finding of a study published in Neurology. Researchers found that among older adults with no signs of frailty, high blood pressure was linked to a higher risk of dementia—consistent with decades of medical advice. But among those who were frail or pre-frail, the relationship was reversed: Elevated blood pressure was associated with a lower dementia risk.
The finding raises the question of whether blood pressure should be viewed the same for every individual, but it also draws concern from experts who worry it could be misread as a license to ease off treatment in vulnerable patients.
What the Study Found
Researchers analyzed data from 6,135 older adults with an average age of 75 who participated in the Atherosclerosis Risk in Communities Neurocognitive Study and were followed for up to 11 years. None had dementia at the start.
Participants were classified as frail if they had at least three of the following: low energy, low physical activity, slow walking speed, weakness, and weight loss. Those with one or two characteristics were considered pre-frail; those with none were non-frail.
The key result: Among non-frail participants, high blood pressure—defined as at least 130/80 millimeters of mercury (mm Hg), or use of blood pressure medication—was associated with a 39 percent higher relative risk of dementia compared with normal blood pressure.
Among participants who were pre-frail or frail, elevated blood pressure—120 to 129 mm Hg systolic, under 80 mm Hg diastolic—was associated with a 32 percent lower relative risk. The apparent protective association was observed in the elevated blood pressure group rather than among people with more severe hypertension.
“While high blood pressure is still a concern for the majority of people, we may need to look at people’s overall health and whether they are showing signs of frailty as we consider how to manage their blood pressure,” study author Jason Smith, a postdoctoral researcher at the University of North Carolina, told The Epoch Times.
Why Frailty May Change the Relationship
Researchers have proposed several explanations for the unexpected findings.
In healthy people, blood vessels are flexible and can constrict when blood pressure falls, helping maintain blood flow to vital organs. With aging and years of hypertension, however, arteries can become stiffer, potentially reducing their ability to adjust to changes in blood pressure.
One possibility is that in people with advanced frailty, slightly higher blood pressure may help maintain adequate blood flow to the brain and other organs when the cardiovascular system is less able to compensate for a drop in pressure. Low blood pressure can reduce blood flow to vital organs when it becomes severe enough.
Frailty itself may also complicate the picture. Because frail older adults are more vulnerable to illness, falls, hospitalization, and death regardless of blood pressure, the observed association may reflect underlying health status rather than a protective effect of higher blood pressure.
The findings also align with several previous observational studies.
A 2019 review of observational studies that followed older adults for about six years found that among frail older adults, those with systolic blood pressure above 140 mm Hg had mortality rates similar to those with lower blood pressure, suggesting that high blood pressure may not carry the same risks in frail adults.
A 2021 study found similar patterns: Frail older adults had the highest mortality regardless of blood pressure level, while non-frail adults with lower blood pressure fared better.
These studies raise the question of whether blood pressure targets should always be the same for every older adult.
Current guidelines, however, haven’t caught up to this nuance. The 2025 American Heart Association and American College of Cardiology guidelines recommend an overall treatment goal below 130/80 mm Hg for adults, while acknowledging that goals may need adjustment for frailer patients.
Evidence from randomized clinical trials also continues to support blood pressure treatment in most older adults. In the Systolic Blood Pressure Intervention Trial (SPRINT), intensive blood pressure control in adults aged 75 and older reduced major cardiovascular events and overall mortality by roughly one-third.
Why Experts Urge Caution
Not everyone is convinced this finding should change how frail older adults are treated.
The findings could be interpreted as supporting less aggressive blood pressure treatment in frail older adults despite being based on an observational association, Dr. Jurgen Claassen, a professor of geriatrics at Radboud University Medical Center, told The Epoch Times.
“My worry is that frail older people who have hypertension have a very high risk of stroke, heart failure and myocardial infarction. This means that ‘accepting’ a blood pressure level of 150 or 160 mm Hg will not lower their risk of dementia but may actually increase it, as well as increase their risk of death or disabling stroke or heart failure,” Claassen said.
He has also challenged the theory that frail older adults require higher blood pressure to maintain adequate brain blood flow, noting that evidence suggests older adults generally maintain normal cerebral blood flow even at lower blood pressure levels.
The recent study adds to an ongoing debate in geriatric medicine about how aggressively blood pressure should be managed in frail older adults. However, treatment decisions should be individualized and based on a person’s overall health, rather than blood pressure alone, Smith said.