The Association Between Blood Pressure and Incident Alzheimer Disease

Abstract

Background Many epidemiologic studies have considered the association between blood pressure (BP) and Alzheimer disease, yet the relationship remains poorly understood. Methods In parallel with work on the AlzRisk online database (www.alzrisk.org), we conducted a systematic review to identify all epidemiologic studies meeting pre-specified criteria reporting on the association between hypertension, systolic BP, or diastolic BP and incident Alzheimer disease. When possible, we computed summary measures using random-effects models and explored potential heterogeneity related to age at BP assessment. Results Eighteen studies reporting on 19 populations met the eligibility criteria. We computed summary relative risks (RRΣ) for three measures of BP: hypertension (RRΣ=0.97 [95% confidence interval= 0.80–1.16]); a 10 mm Hg-increase in systolic BP (RRΣ=0.95 [0.91–1.00]); and a 10 mm Hg-increase in diastolic BP (RRΣ=0.94 [0.85–1.04]). We were unable to compute summary estimates for the association between categories of systolic or diastolic BP and Alzheimer disease; however, there did not appear to be a consistent pattern across studies. After stratifying on age at BP assessment, we found a suggestion of an inverse association between late-life hypertension and Alzheimer disease and a suggestion of an adverse association between midlife diastolic hypertension and Alzheimer disease. Conclusions Based on existing epidemiologic research, we cannot determine whether there is a causal association between BP and Alzheimer disease. Selection bias and reverse causation may account for the suggested inverse association between late-life hypertension on Alzheimer disease, but, given the expected direction of these biases, they are less likely to account for the suggestion that midlife hypertension increases risk. We advocate continuing systematic review; the Alzrisk database entry on this topic (www.alzrisk.org), which was completed in parallel with this work, will be updated as new studies are published.

Summary of the evidence on modifiable risk factors for cognitive decline and dementia: A population‐based perspective

“…Meta-analyses of clinical trials and prospective, observational, longitudinal, and cross-sectional studies, including a Cochrane review, have not indicated a consistent relationship between high blood pressure and dementia; there is stronger evidence for a link with cognitive decline [43][44][45][46][47]. A systematic review of meta-analyses, observational studies, and randomized controlled trials found treatments of hypertension may reduce the risk of cognitive decline [48]; a metaanalysis of longitudinal studies concluded the opposite [49].…”

Prevention of Vascular Cognitive Impairment

“…177 As demonstrated by a recent meta-analysis hypertension is associated with an increased risk of incident VaD (OR=1.59; 1.29-1.95) 87 whereas the relationship is less clear for AD. 92,93,94 Among subjects not taking antihypertensive medication in the Honolulu Asia Aging Study (HAAS) 27% of late-life dementia cases were attributable to midlife SBP levels >120mmHg. 98 Despite conclusive evidence for the role of hypertension there is considerable uncertainty regarding the efficacy of antihypertensive treatment for lowering the risk of dementia: Observational studies: Published data suggest some preventive effect of antihypertensive treatment when given to younger people.…”

Hypertonie und die Folgen für kognitive Funktionsstörungen und Demenz

“…Während die Datenlage für die Korrelation von Hypertonie und vaskulärer Demenz somit klar belegt wurde, ist der Zusammenhang zwischen Hypertonie und einer Alzheimer-Demenz nicht eindeutig bewiesen [30,31]. Die Bedeutung der schlecht eingestellten oder nicht behandelten Hypertonie liegt wahrscheinlich in einer schnelleren Progredienz der Krankheit.…”