Patients between the ages of 55 and 64 could face faster cognitive decline over five years if their blood pressure measurements vary significantly from visit to visit than if it stays stable between measurements.
The findings, from a new study in the journal Hypertension of the American Heart Association, stand when looking at either systolic or diastolic blood pressure—and with these visit-to-visit variables, the faster cognitive declines come independent of the trend of the patient’s overall mean blood pressure.
The study authors explained that the results give a new understanding to the relationship between blood pressure and the cognitive abilities of older adults. Previously, the link between later-in-life high blood pressure was not very well elaborated, and the variability in measurements between visits was thought to be random.
Now, the study authors said, it is clear that later-in-life visit-to-visit variability in blood pressure might be more important than the mean blood pressures that were measured against cognitive decline.
The researchers found several factors that correlated with higher variability in the blood pressure measurements. They found that living in more urban areas, having a history of stroke or diabetes, taking anti-hypertension drugs, finishing lower levels of education and having lower activity levels predicted that patients would have a higher change in their systolic blood pressure readings from visit to visit. And when looking at diastolic blood pressure readings, higher variability was found in patients who were younger, taking anti-hypertension drugs and had a history of heart attack.
The risks outlined for such variability include higher incidence of stroke for younger patients and a faster decline in verbal memory. And the incidence of faster cognitive decline among younger patients was especially related to highly variable diastolic blood pressure readings over the course of the study.
It’s not clear exactly why high blood pressure variability could be so damaging to cognitive ability. The study authors said it’s possible the fluctuations are causing brain lesions and bleeding that have a negative effect over time, or that it could cause cerebrovascular diseases that erodes the blood-brain barrier.
The study authors said their data supports the idea that blood pressure treatment plans should move away from focusing on mean blood pressure measurements when trying to prevent dementia. Instead, they said the focus should move toward controlling blood pressure instability, rather than controlling the overall measurements of a patient’s blood pressure.