Blood pressure variability linked to impaired cognition in older adults

Key takeaways:

• Greater blood pressure variability over time was linked to lower cognitive scores in older adults.
• The link between blood pressure variability and cognition was only significant in Black adults.

In older adults, particularly Black adults, elevated blood pressure variability was associated with lower cognitive score at follow up, according to a study published in Neurology, the medical journal of the American Academy of Neurology.

These results suggest that blood pressure management, including regular assessment, may help to preserve cognitive function among older adults, the researchers wrote.

“With our aging society and the prevalence of Alzheimer’s disease, identifying prevention strategies to slow the decline of cognitive skills in older adults has become a public health priority,” Anisa Dhana, MD, MSc, a postdoctoral researcher with the Rush Institute of Healthy Aging and the department of internal medicine at Rush University Medical Center, said in an American Academy of Neurology press release.

Previous studies have demonstrated that hypertension is associated with worse cognition scores and increased risk for dementia and Alzheimer’s disease. However, researchers have not thoroughly investigated how blood pressure variability (BPV) relates to cognition in older Black adults, particularly compared with their white counterparts.

This inspired Dhana and colleagues to perform a prospective, observational cohort study using participants enrolled in the Chicago Health and Aging Project (CHAP), a biracial population-based trial that took place from 1993 to 2012.

The analysis included 4,470 adults (62.9% women; 66% Black; mean age, 71.3 years; standard deviation [SD], 5.3 years) aged 65 years or older with three or more blood pressure measurements, collected every 3 years over the 18-year CHAP study period, which were used to calculate BPV.

CHAP researchers also calculated z scores for a composite cognitive score, measured through neuropsychological function tests that evaluated memory, attention, processing speed and more.

The researchers found that over a mean follow-up period of 10 years, the mean systolic BPV was 17.7 mm Hg for Black adults and 16 mm Hg for white adults.

Overall, results showed that higher systolic and diastolic BPV was associated with lower cognitive scores at the last study visit. Specifically, cognition z scores were lower with each one-SD increase in systolic and diastolic BPV (systolic: B = –0.03; 95% CI, –0.055 to –0.006; diastolic: B = –0.033; 95% CI, –0.057 to –0.01).

Additionally, compared with participants in the first tertile of BPV, indicating low variability, participants with higher BPV in the third tertile had lower cognitive scores for systolic (B = –0.074; 95% CI, –0.131 to –0.018) and diastolic (B = –0.062; 95% CI, –0.118 to –0.007) BPV, equating to older cognitive age by 1.8 years for systolic BPV and 1.5 years for diastolic BPV.

However, the association between BPV and cognitive function differed by race, as this relationship was only significant among older Black adults. The researchers found that an increase of one SD in systolic and diastolic BPV was associated with lower cognitive scores (systolic: B = –0.04; 95% CI, –0.069 to –0.011; diastolic: B = –0.048; 95% CI, –0.076 to –0.02) in older Black adults.

Again, compared with Black adults in the first tertile of BPV, those in the third tertile had lower cognitive scores for systolic (B = –0.115; 95% CI, –0.183 to –0.047) and diastolic (B = –0.097; 95% CI, –0.165 to –0.03) BPV, as well as older cognitive age (systolic: 2.8 years older; diastolic: 2.4 years older).

Additionally, the researchers did not find an association between BPV and lower cognitive scores among participants who were taking antihypertensive medications at baseline. However, among participants who were not taking antihypertensive medications at baseline, cognitive scores were lower among those in the second tertile (B = –0.096; 95% CI, –0.18 to –0.012) and third tertile (B = –0.105; 95% CI, –0.198 to –0.012) of systolic BPV compared with those in the first tertile.

The researchers noted several limitations to this study, including the limited generalizability of these findings to other races and potential selection bias, given they only included participants with three or more blood pressure readings.

“These results suggest that fluctuation in blood pressure is a risk factor for cognitive problems beyond the negative effects of high blood pressure itself,” Dhana said in the release. “Older adults should be routinely monitored for their blood pressure and any changes over time so we can identify people who may have this issue and work to alleviate it, which could potentially help to prevent or delay cognitive problems.”

Reference:

• Fluctuating blood pressure tied to problems with thinking. https://www.newswise.com/articles/fluctuating-blood-pressure-tied-to-problems-with-thinking-skills. Published Dec. 5, 2024. Accessed Dec. 11, 2024.