Researchers assesed results from 976 Chinese adults, 50% women, age 55 and or older, in the China Health and Nutrition Survey over a period of five years.
Blood pressure variability was derived from three or four visits to the health professional. Participants also went through a series of cognitive quizzes, like word recall tasks and counting backwards.
Bonnie Qin, Ph.D., lead study author and a postdoctoral scholar at Rutgers Cancer Institute in New Brunswick, New Jersey, said:
“Blood pressure variability might signal blood flow instability, which could lead to the damage of the finer vessels of the body with changes in brain structure and function. These blood pressure fluctuations may indicate pathological processes such as inflammation and impaired function in the blood vessels themselves.”
Qin added physicians tend to focus on average blood pressure readings, but high variability may be something for physicians to watch for in their patients.
Researchers found that higher visit-to-visit variability in the top number in a blood pressure reading (systolic blood pressure) was linked with a faster decline of cognitive function and verbal memory.
But higher visit-to-visit variability in the bottom number (diastolic blood pressure) was associated with faster decline of cognitive function among adults ages 55 to 64, but not among those age 65 and older.
“Controlling blood pressure instability could possibly be a potential strategy in preserving cognitive function among older adults,” Qin said.
Although the study, published in American Heart Association’s journal Hypertension, was observational and does not imply a direct cause and effect between blood pressure variability and brain function decline, the findings add to a growing body of evidence that variation in blood pressure readings may indicate increased risk for some additional health problems. Clinical trials and longer term studies will be needed to confirm the findings.