Abstract 22: Visit-to-Visit Variability in Blood Pressure is Related to Late-Life Cognitive Decline

Abstract

Introduction: Recent studies suggest higher visit-to-visit variability of blood pressure (BP) is associated with worse cognitive function, but evidence based on longitudinal cognitive testing has not been reported. Hypothesis: 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. Methods: This prospective cohort study comprised 1213 adults who had two or more waves of BP measurements as part of the China Health and Nutrition Survey from 1991, up to their first cognitive tests, and completed a cognitive screening test at two or more waves in 1997, 2000 or 2004. Mean (SD) age at first cognitive test was 64 (6) y. Outcomes were repeated measures of global cognitive scores (baseline mean ± SD: 19 ± 6 points), standardized composite cognitive and verbal memory scores (standardized units [SU]). Visit-to visit BP variability was expressed as the standard deviation [SD] or as the variation independent of mean (SD/mean^x, with x derived from curve fitting) in BP measures obtained at a mean interval of 3.6 years. Multivariable-adjusted linear mixed-effects models were used to determine the association of changes in cognitive scores with visit-to visit BP variability. Results: 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 in variability (Figure): global score -0.23 points/y [-0.41 to -0.04], composite scores -0.029 SU/y [-0.056 to -0.002] and verbal memory -0.044 SU/y [-0.075 to -0.012]). Higher visit-to-visit variability in diastolic BP was associated with a faster decline of global cognitive function only among adults 55-64 years, independent of mean diastolic BP. Conclusion: Higher long-term BP visit-to-visit variability predicted a faster rate of cognitive decline among older adults.