Low untreated systolic blood pressure over 18 years is associated with survival free of dementia age 90+

INTRODUCTION: We hypothesized that lower untreated systolic blood pressure (SBP) would be associated with a lower risk of dementia and death up to age 95. METHODS: SBP measured between 2000 and 2006 was evaluated in relationship to dementia risk and brain biomarkers from 2009‐2020 (n = 177) in the Gingko Evaluation of Memory Study (GEMS), mean age 95 in 2020. Participants had measurements of brain amyloid beta (Aβ) and repeat clinical‐cognitive evaluations every 6 months. RESULTS: By 2020, only 9 of 177 patients (5%) were alive and cognitively unimpaired (CU). Mean SBP from 2000 to 2006 was 120 mm Hg for nine alive/CU, 125 mm Hg for alive/mild cognitive impairment (MCI), and 130 mm Hg for alive/dementia (P = .03). The amount of Aβ was directly related to SBP levels. In multivariate analysis, Aβ+ in 2009 and thinner cortex were significant predictors of dementia. Excluding Aβ, SBP became a significant predictor of dementia. DISCUSSION: Low SBP untreated by antihypertensive medications was associated with significant decreased risk of dementia and less Aβ.