A new study by Cedars-Sinai investigators found that people whose blood pressure fluctuated while they were in the hospital were at greater risk for developing Alzheimer’s disease or other types of dementia than people whose blood pressure remained stable while hospitalized. 

The findings, published in Frontiers in Neurology suggest blood pressure readings could be used to identify people at risk for dementia—a general term used to describe conditions that progressively destroy memory and cognitive ability.

“Scientists used to think it was only amyloid plaques and tangles that cause Alzheimer’s and related dementias, but now there is increasing understanding that there is also a vascular contribution,” said Zaldy Tan, MD, MPH, medical director of the Jona Goldrich Center for Alzheimer’s and Memory Disorders at Cedars-Sinai and senior author of the study. 

Blood pressure readings include the systolic pressure, or higher number, which measures the pressure within the arteries when the heart beats, and the diastolic pressure, or lower number, which measures the pressure in the arteries when the heart rests between beats.

People with high blood pressure are more likely to develop dementia, as are people whose blood pressure tends to fluctuate from day to day, according to published research. 

“Blood pressure normally fluctuates over time due to changes in our cardiovascular, nervous, and endocrine systems as well as environmental factors,” said Tan, who is also the Carmen and Louis Warschaw Chair in Neurology. “These fluctuations tend to be more pronounced in people with high blood pressure.”

Previous studies found increased dementia risk for people whose blood pressure varied between readings taken at home or at doctors’ visits. Tan and colleagues wanted to understand whether this was also the case for people who experience variability during hospital stays.

The investigators reviewed the health records of 81,892 people who were hospitalized between January 1, 2013 and December 31, 2019. The average age of the patients was 56 and none had previously been diagnosed with Alzheimer’s or another type of dementia. The patients were hospitalized for a median of three days, and 9% of them were admitted to the intensive care unit. The most common health issues among the people who were hospitalized were hypertension (29% of patients), depression (12%), coronary artery disease (12%) and diabetes (10%). 

Two years after they were discharged from the hospital, a total of 2,442 (3%) people in the study developed Alzheimer’s or another dementia. 

The investigators found that people whose blood pressure fluctuated were more likely to develop dementia than those whose blood pressure remained stable. 

The study also revealed that the greater a person’s average systolic blood pressure, the higher the person’s chances were of developing dementia within two years.

“These findings underscore the need to keep blood pressure stable,” said Joseph Ebinger, MD, a clinical cardiologist and director of Clinical Analytics at the Smidt Heart Institute at Cedars-Sinai and first author of the study. “It’s well known these practices contribute to good cardiovascular health, and now we know they may improve a person's risk for dementia.”  

Investigators are still trying to understand the biological processes that might explain why blood pressure variability increases a person’s risk for developing dementia. One hypothesis is that when blood pressure dips from high to low or vice versa, it could damage the tiny blood vessels in the brain. 

Tan and colleagues are continuing to study the association between blood pressure variability and dementia in studies that involve more patients and that track the participants’ health over several years. 

Other Cedars-Sinai investigators who worked on the study include Matthew Driver, Patrick Botting, Minhao Wang and Susan Cheng, MD. 

Funding: The study was funded by Cedars-Sinai Medical Center, the Erika J Glazer Family Foundation and the National Institutes of Health (award numbers R01-HL131532 and K23-HL153888).