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Consistent cerebral blood flow (CBF) is fundamental to brain function. Cerebral autoregulation ensures CBF stability. Chronic hypertension can lead to disrupted cerebral autoregulation in older people, potentially leading to blood pressure levels interfering with CBF. This study tested whether low BP and AHD use are associated with contemporaneous low CBF, and whether longitudinal change in BP is associated with change in CBF, using arterial spin labelling (ASL) MRI, in a prospective longitudinal cohort of 186 community-dwelling older individuals with hypertension (77 ± 3 years, 53% female), 125 (67%) of whom with 3-year follow-up. Diastolic blood pressure, systolic blood pressure, mean arterial pressure, and pulse pressure were assessed as blood pressure parameters. As additional cerebrovascular marker, we evaluated the ASL signal spatial coefficient of variation (ASL SCoV), a measure of ASL signal heterogeneity that may reflect cerebrovascular health. We found no associations between any of the blood pressure measures and concurrent CBF nor between changes in blood pressure measures and CBF over three-year follow-up. Antihypertensive use was associated with lower grey matter CBF (-5.49 ml/100 g/min, 95%CI = -10.7|-0.27, p  = 0.04) and higher ASL SCoV (0.32 SD, 95%CI = 0.12|0.52, p  = 0.002). These results warrant future research on the potential relations between antihypertensive use and cerebral perfusion.

Objective: To assess whether angiotensin II-stimulating antihypertensives (thiazides, dihydropyridine calcium channel blockers, and angiotensin I receptor blockers) convey a lower risk of incident dementia compared to angiotensin II-inhibiting antihypertensives (angiotensin-converting enzyme inhibitors, β-blockers, and nondihydropyridine calcium channel blockers), in accordance with the "angiotensin hypothesis.", Methods: We performed Cox regression analyses of incident dementia (or mortality as competing risk) during 6-8 years of follow-up in a population sample of 1,909 community-dwelling individuals (54% women) without dementia, aged 70-78 (mean 74.5 ± 2.5) years., Results: After a median of 6.7 years of follow-up, dementia status was available for 1,870 (98%) and mortality for 1,904 (>99%) participants. Dementia incidence was 5.6% (27/480) in angiotensin II-stimulating, 8.2% (59/721) in angiotensin II-inhibiting, and 6.9% (46/669) in both antihypertensive type users. Adjusted for dementia risk factors including blood pressure and medical history, angiotensin II-stimulating antihypertensive users had a 45% lower incident dementia rate (hazard ratio [HR], 0.55; 95% CI, 0.34-0.89) without excess mortality (HR, 0.86; 95% CI, 0.64-1.16), and individuals using both types had a nonsignificant 20% lower dementia rate (HR, 0.80; 95% CI,0.53-1.20) without excess mortality (HR, 0.97; 95% CI, 0.76-1.24), compared to angiotensin II-inhibiting antihypertensive users. Results were consistent for subgroups based on diabetes and stroke history, but may be specific for individuals without a history of cardiovascular disease., Conclusions: Users of angiotensin II-stimulating antihypertensives had lower dementia rates compared to angiotensin II-inhibiting antihypertensive users, supporting the angiotensin hypothesis. Confounding by indication must be examined further, although subanalyses suggest this did not influence results. If replicated, dementia prevention could become a compelling indication for older individuals receiving antihypertensive treatment., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objectives: To evaluate whether discontinuation of antihypertensive medication in community-dwelling older people is associated with a reduction in memory complaints and/or incident dementia., Design: Prospective observational cohort study within the Prevention of Dementia by Intensive Vascular Care (preDIVA) trial., Setting and Participants: Community-dwelling participants (aged 70-78 years at baseline) who underwent 2-yearly assessments during 6-8 years of follow-up., Measures: Cox regression analyses of the relation between discontinuation of antihypertensive medication during the study and change in subjective memory complaints, incident dementia, and mortality., Results: Dementia occurred more often in participants discontinuing antihypertensive treatment (13.4% vs 6.2%, P = .02); mortality was similar (16.5% vs 13.9%, P = .52). Discontinuation of antihypertensive medication was associated with a double dementia hazard [hazard ratio (HR) (95% confidence interval) = 2.15 (1.15-4.03)], which somewhat attenuated after adjustment for sex, blood pressure, number of antihypertensives and other medications [HR = 1.92 (1.01-3.65)], and additionally for stroke, cardiovascular disease, diabetes, smoking, memory complaints, and MMSE score [HR = 1.79 (0.93-3.44)]. Antihypertensive discontinuation was associated with an approximately 50% higher hazard of dementia and/or mortality combined [HR = 1.58 (1.04-2.40); model 2: HR = 1.64 (1.07-2.51); model 3: HR = 1.49 (0.96-2.30)]. Antihypertensive discontinuation was not associated with change in memory complaints [odds ratio (95% confidence interval) = 0.96 (0.55-1.67)]. Subgroup and sensitivity analyses addressing possible sources of bias and confounding gave similar results., Conclusions/implications: Our results suggest that antihypertensive withdrawal in community-dwelling older people does not preserve cognition and may in fact increase dementia risk. This is not due to reduced mortality as competing risk. Additional analyses suggest results are unlikely to be explainable by confounding, reverse causality, or observational biases. Studies with person-specific reasons for antihypertensive discontinuation may be able to exclude reverse causality completely. Given the beneficial effects of antihypertensive medication on cardiovascular risk, observational data may be the best currently obtainable on the pressing issue of when withdrawal of antihypertensives in older people is acceptable and what consequences need to be weighed., (Copyright © 2018 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

To systematically review and synthesize the evidence on differential associations between antihypertensive medication (AHM) classes and the risk of incident dementia. Systematic review and random effects frequentist network meta-analysis. Embase, MEDLINE, and the Cochrane library were searched from origin to December 2019. Randomized controlled trials (RCTs) and prospective cohort studies that compared associations of different AHM classes with incident all-cause dementia and/or Alzheimer's disease over at least 1 year of follow-up. All cause dementia and/or Alzheimer's disease. Fifteen observational studies and 7 RCTs were included. Data on AHM classes were available for 649,790 participants and dementia occurred in 19,600 (3.02%). Network meta-analysis showed that in observational studies, treatment with either calcium channel blockers (CCBs) or angiotensin II receptor blockers (ARBs) was associated with lower dementia risks than treatment with other antihypertensives: CCBs vs angiotensin converting enzyme inhibitors (ACE inhibitors) (HR=0.84, 95% CI 0.74-0.95), beta blockers (HR=0.83, 95% CI 0.73-0.95) and diuretics (HR=0.89, 95% CI 0.78-1.01) and ARBs vs ACE inhibitors (HR=0.88, 95% CI 0.81-0.97), beta blockers (HR=0.87, 95% CI 0.77-0.99), and diuretics (HR=0.93, 95% CI 0.83-1.05). There were insufficient RCTs to create a robust network based on randomized data alone. Recommending CCBs or ARBs as preferred first-line antihypertensive treatment may significantly reduce the risk of dementia. If corroborated in a randomized setting, these findings reflect a low-cost and scalable opportunity to reduce dementia incidence worldwide. [ABSTRACT FROM AUTHOR]