Affiliations: [a] School of Medicine, University of New South Wales, NSW, Australia
| [b] Centre for Healthy Brain Aging, University of New South Wales, NSW, Australia
| [c] Department of Neuropsychiatry, Prince of Wales Hospital, NSW, Australia
Correspondence:
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Correspondence to: Matthew Lennon, MD, University of New South Wales, NSW, Australia. E-mail: matthew.lennon@unsw.edu.au.
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 meta-analyses 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 I2 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.
