Midlife Hypertension and Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Abstract

Background: Hypertension is an established risk factor for stroke and vascular dementia but recent meta-analyses examining the association between Alzheimer's disease (AD) and hypertension have found no significant association. These metaanalyses included short term studies starting in late life which may have obscured the real effect of midlife hypertension. Objective: To examine the association of AD with midlife hypertension, by including only studies with a sufficiently long follow up duration. Methods: Relevant studies were found by searches of MEDLINE, EMBASE, and PubMed. Study outcomes were grouped by measures of blood pressure and definition of hypertension (e.g., systolic hypertension > 140 mmHg or > 160 mmHg). We assessed pooled effect estimates using random effects models and heterogeneity of pooled estimates through the I 2 statistic. Results: Literature search found 3,426 publications of which 7 were eligible studies. There was a significant association between systolic hypertension (>160 mm Hg) and AD (HR 1.25, 95CI 1.06 -1.47, p = 0.0065). Similarly, for systolic hypertension > 140 mm Hg, there was a smaller but still significant association (HR 1.18, 95CI 1.02 -1.35, p = 0.021). For diastolic hypertension, all four studies found no significant associations between diastolic hypertension and AD, and these data could not be pooled due to heterogeneity in reporting. Conclusions: Our study found that midlife stage 1 and stage 2 systolic hypertension is associated with increased risk of AD by 18 and 25%, respectively, although no association was found for diastolic hypertension. It is likely that assertive control of systolic hypertension starting in midlife is important to preventing AD.

Impact of cardiovascular risk factors and genetics on 10-year absolute risk of dementia: risk charts for targeted prevention

“…Smoking associates with increased risk of dementia, 24 , 27 and is likely mediated by cardiovascular pathology and the content of neurotoxins in cigarette smoke. 1 , 28 Midlife hypertension is consistently associated with increased risk of dementia 1 , 5 , 29 —an association we can confirm at least for men in the present study—and is suggested to be through increased risk of cerebrovascular disease and the metabolic syndrome. 1 Physical activity is inversely associated with risk of dementia, 1 , 5 , 30 an association mainly explained by cardiovascular risk factors.…”

Association of arsenic exposure and cognitive impairment: a population-based cross-sectional study in China

“…CI had higher SBP than CN in this study. A Meta-analysis showed a correlation between SBP and AD, meanwhile no correlation for DBP [25], which was consistent with our research. Our study found that CI had a higher PSQI score than CN, which represented a worse quality of sleep.…”

Causes and consequences of baseline cerebral blood flow reductions in Alzheimer’s disease

“…80 A recent metaanalysis studied this correlation in more depth and showed that, in particular, stage one (BP > 140 mm Hg/90 mm Hg (systolic/diastolic)) or two (BP > 160 mm Hg/95 mm Hg) systolic hypertension, but not diastolic hypertension (> 90 mm Hg distolic), was associated with more severe AD. 81 These cardiovascular risk factors are all associated with brain blood flow reductions and increased microemboli, 82 and it may be, in part, through these flow reductions that these cardiovascular risk factors influence AD progression. In addition, cardiovascular disease, such as coronary heart disease or small vessel disease, is associated with brain hypoperfusion (largest in watershed regions, including the basal ganglia, white matter, and hippocampus [83][84][85] ) and has been shown to increase the risk of developing MCI and dementia.…”