Hypertension and Alzheimer's disease pathology at autopsy: A systematic review: Human neuropathology/amyloid.

Background: Hypertension is an important risk factor for all‐cause dementia and Alzheimer's disease (AD). Reports about the relation between mid‐life hypertension and AD‐related neuropathology are sparse and inconsistent. We conducted a systematic review to collate and synthesize the literature on the relation between hypertension and AD neuropathology. Methods: Search terms included dementia, Alzheimer's disease, hypertension, autopsy, obduction and neuropathology. The main outcome was AD‐related neuropathological changes at autopsy (including amyloid plaques and neurofibrillary tangles) with hypertension as exposure, either collected retrospectively from medical records or prospectively measured at clinical evaluation(s). We included prospective and retrospective cohort studies with individuals from general and selected (e.g. memory clinic) populations. We excluded case‐control studies. Results: We found 10 studies (total N = 3054, median 231 participants, range 50‐1288) that were very heterogeneous concerning populations, methodological approach and statistical analysis. Most studies reported no association between midlife hypertension and AD‐changes at autopsy. Two studies (total n = 1531) reported an association between hypertension and elevated numbers of neurofibrillary tangles and neuritic plaques. Of those studies, one reported that both a low and a high BP in late‐life was associated with an increased burden of amyloid plaques and tangles (U‐shape). Conclusions: Our study shows no consistent association between blood pressure and AD‐neuropathology. However, based on our results, we speculate that the association between hypertension and AD‐neuropathology is age‐dependent, and that U‐shaped relations may have been obscured in linear analyses. Future studies could take this phenomenon into account when investigating the relation between hypertension and AD neuropathology. [ABSTRACT FROM AUTHOR]