Associations of orthostatic hypotension with dementia in older adults: A 12‐year follow‐up population‐based study

Abstract

AbstractBackgroundOrthostatic hypotension (OH) has been linked to dementia in older people in several longitudinal studies. We sought to examine the associations of OH with all‐cause dementia and subtypes of dementia, and further to explore the potential modifying effects of APOE ε4 allele and impaired walking speed on their associations.MethodThis population‐based cohort study included 2,525 dementia‐free participants who had their postural blood pressure measured at baseline (2001‐2004) and were regularly examined until 2013‐2016 in the Swedish National study on Aging and Care in Kungsholmen (SNAC‐K). OH was defined as systolic blood pressure decreases ≥20 mmHg or diastolic blood pressure decreases ≥10 mmHg when assuming the upright position. Dementia was diagnosed according to the DSM‐IV criteria. Alzheimer dementia and vascular dementia were diagnosed following the NINCDS‐ADRDA criteria and the NINDS‐AIREN criteria, respectively. Walking speed was measured through 2.4‐meter or 6‐meter walk test and impaired walking speed was defined as <0.8 m/s. Data were analyzed with Cox proportional‐hazards models after controlling for multiple potential confounders.ResultAt baseline, 613 (24.3%) participants were defined to have OH. During the 12‐year follow‐up periods, 370 people (14.7%) were diagnosed with dementia, including 198 with Alzheimer dementia and 67 with vascular dementia. OH was significantly associated with a multiple‐adjusted hazard ratio (HR) of 1.39 (95% CI: 1.10‐1.76) for all‐cause dementia, 1.58 (1.15‐2.16) for Alzheimer dementia, and 1.20 (0.70‐2.05) for vascular dementia. To further reduce the potential of reverse causality, we repeated the analysis after excluding dementia cases that were diagnosed within the first 3 years of the follow‐up periods, and the results suggested that OH was still significantly associated with all‐cause dementia (HR: 1.33, 95% CI: 1.01‐1.75) and Alzheimer dementia (HR: 1.63, 95% CI: 1.22‐2.19). There was no statistical interaction of OH with either APOE ε4 allele or impaired walking speed on the risk of dementia (p‐value for both interaction tests >0.10).ConclusionOH is associated with an elevated risk of dementia, especially Alzheimer dementia, among older adults. Neither APOE ε4 allele nor impaired walking speed could modify the association of OH to dementia.