Blood pressure variability and cognitive decline in older people: a 5-year longitudinal study

Background: Cognitive impairment is common in later life. Identifying potential modifiable risk factors for cognitive decline may ameliorate the burden of disease. Cross-sectional studies show an association between blood pressure (BP) variability and impaired cognitive function in patients with hypertension and/or dementia. However, research examining the association between BP variability and cognitive function in the general older population is scarce. Objective: In this study, we examined the association between BP variability and cognitive function over 5-year follow-up in an unselected community-dwelling cohort. Methods: Ambulatory BP monitoring was performed in 353 community-dwelling people aged at least 65 years. Cognitive assessment, using the Mini Mental State Examination (MMSE) and Cambridge Cognitive Examination (CAMCOG), was performed at baseline and at 5-year follow-up. BP variability was calculated using the coefficient of variation. Cognitive change over 5 years was defined as baseline score minus follow-up score. Results: Increased daytime systolic variability was associated with poorer performance on the CAMCOG total score and subscores. Daytime diastolic variability was associated with poorer performance on total CAMCOG, CAMCOG executive score, and MMSE. These findings were independent of demographic and cardiovascular risk factors. Daytime systolic variability was also independently associated with greater decline in total CAMCOG and MMSE scores over 5-year follow-up. Conclusion: Increased BP variability is associated with poorer cognitive function in older people and may represent a novel modifiable risk factor for cognitive decline.