Visit-to-Visit Variability in Blood Pressure Is Related to Late-Life Cognitive Decline

Abstract

The association between visit-to-visit variability of blood pressure (BP) and cognitive decline over time remains incompletely understood in a general population of older adults. We assessed the hypothesis that higher visit-to-visit variability in BP, but not mean BP, would be associated with faster decline in cognitive function among community-dwelling older adults. This prospective cohort study comprised 976 adults who had 3 or 4 visits with BP measurements as part of the China Health and Nutrition Survey from 1991, up to their first cognitive tests, and completed cognitive screening tests at 2 or more visits in 1997, 2000 or 2004. Visit-to visit BP variability was expressed as the standard deviation (SD), coefficient of variation or as the variation independent of mean BP across visits conducted at a mean interval of 3.2y. Mean (SD) age at the first cognitive test was 64 (6)y. Using multivariable-adjusted linear mixed-effects models, we found higher visit-to-visit variability in systolic BP, but not mean systolic BP, was associated with a faster decline of cognitive function (adjusted mean difference [95% CI] for high vs. low tertile of SD variability: standardized composite scores −0.038 standardized units (SU)/y [−0.066, −0.009] and verbal memory −0.041 SU/y [−0.075 to −0.008]). Higher visit-to-visit variability in diastolic BP was associated with a faster decline of cognitive function, independent of mean diastolic BP, among adults 55–64y but not those ≥ 65y. Our results suggest that higher long-term BP visit-to-visit variability is associated with a faster rate of cognitive decline among older adults.

Long‐Term Blood Pressure Level and Variability From Midlife to Later Life and Subsequent Cognitive Change: The ARIC Neurocognitive Study

“…These measures have been used in previous studies of BP variability 13, 14, 15, 16, 17, 18. Average real variability (ARV) is the average absolute difference between successive BP measurements and, in contrast with SD and CV, it takes into account the order of the clinic visits at which BP was measured 19, 20.…”

“…In addition to BP levels, BP variability may be associated with cognitive function 12, 13, 14, 15, 16, 17, 18. BP variability consists of short‐term BP variability (eg, within 24 hours) and long‐term BP variability (eg, visit‐to‐visit BP variability) 19, 20.…”

“…The association between greater long‐term BP variability and lower cognitive function has been recently highlighted in European and Asian studies,13, 14, 15, 16, 17, 18 although reports from studies of US populations are limited. Cognitive function was assessed at a single time point in these European and Asian studies13, 14, 15 and, thus, it remains to be determined whether long‐term BP variability is associated with cognitive function only concurrently or whether it is also related to individual cognitive decline.…”

Blood pressure variability and neurocognitive functioning

“…Far from being a background noise or a phenomenon occurring at random and able to dilute the prognostic value of the average BP measurements, the BP variability (BPV) is increasingly recognized as a causative factor of the alterations in brain structure and function . In the recent years, a growing evidence about the role of the BPV on the onset and course of cognitive impairment and dementia has become available: several cross‐sectional and longitudinal, prospective cohort studies have clearly demonstrated that increased daytime, day‐to‐day and visit‐to‐visit BP oscillations are significantly associated, independently of average and absolute BP levels, with the cognitive dysfunction both in non‐demented and demented patients, and are independent risk factors for the incidence of cognitive impairment and dementia, including Alzheimer's disease and vascular dementia, and the progression of the neuropsychological decline …”

Relationships between residual blood pressure variability and cognitive function in the general population of the PAMELA study

“…13 In the current study, we confirmed the importance of residual individual BP variability, which was the only associated with the reduction of cognitive function assessed by MMSE. 4,5,7,15 However, the agreement is lacking because the Honolulu-Asia Aging Study revealed that SBP ≥ 160 mm Hg was related with 51% lower odds of poor performance on a test of global cognition compared with SBP < 100 mm This suggests that BP variability impacts both sexes and that sex hormones do not have protective or adverse effect on cognitive function.…”