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 visits in 1997, 2000, or 2004. Visit-to-visit BP variability was expressed as the SD, coefficient of variation, or as the variation independent of mean BP across visits conducted at a mean interval of 3.2 years. Mean (SD) age at the first cognitive test was 64 (6) years. 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% confidence interval] for high versus low tertile of SD variability: standardized composite scores -0.038 standard units (SU)/y [-0.066 to -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 aged 55 to 64 years but not those ≥65 years. Our results suggest that higher long-term BP visit-to-visit variability is associated with a faster rate of cognitive decline among older adults.

Keywords: aging; blood pressure; cognition; hypertension; longitudinal studies.

Figure 1

Mean difference in rate of change in global cognitive scores, composite scores, and verbal memory scores by tertiles of mean, SD, CV or VIM of SBP. Values presented in Figure 1 are presented in Table 2 (model 2). CV, coefficient of variation; SBP, systolic blood pressure; SD, standard deviation; SU, standard unit; VIM, variation independent of mean.

Figure 2

Mean difference in rate of change in global cognitive scores, composite scores, and verbal memory scores by tertiles of mean DBP and standard deviation of DBP among different age groups. Values presented in Figure 2 are presented in Supplemental Table 4 (model 2). Age significantly modified the association between standard deviation of DBP and change in global cognitive scores (P=0.01). SD, standard deviation; SU, standard unit.