P2‐300: THE BLOOD PRESSURE LEVEL IS ASSOCIATED WITH PLASMA AMYLOID‐β LEVELS: A CROSS‐SECTIONAL STUDY IN THE SUBURBS OF XI'AN, CHINA

Abstract

A growing body of evidence indicates that hypertension may be a risk factor for Alzheimer's disease (AD). Considering the close relationship between peripheral amyloid-β (Aβ) clearance and brain Aβ deposition, we investigated the potential association between blood pressure (BP) level and plasma Aβ concentrations. A total of 1069 participants (age above 45) from a village in the suburbs of Xi'an, China were enrolled finally. A questionnaire was used to collect vascular risk factors and a validated Chinese version of the Mini-Mental State Examination was used to assess cognition. Apolipoprotein E (ApoE) genotype was detected using polymerase chain reaction (PCR) and Sanger sequencing. Plasma Aβ levels were measured by enzyme linked immunosorbent assay. The associations between BP and plasma Aβ levels were determined by multiple linear regressions. Plasma Aβ1-40 level was higher in hypertension group than that in non- hypertension group (53.41±8.57 pg/ml vs. 51.87±8.92 pg/ml, P=0.002), in elevated SBP group than that in normal SBP group (53.68±8.69 pg/ml vs. 51.88±8.80 pg/ml, P=0.001), in elevated MAP group than that in normal MAP group (54.05±8.79 pg/ml vs. 52.04±8.75 pg/ml, P=0.001 ). After controlling the confounding factors, SBP (b=0.068, P<0.001), DBP (b=0.071, P=0.019) and MAP (b=0.087, P=0.001) were associated with plasma Aβ1-40 level positively, while SBP (b=−0.001, P=0.027), DBP (b=−0.001, P=0.040), and MAP (b=−0.001, P=0.022) were associated with plasma Aβ1-42/Aβ1-40 ratios negatively, but Aβ1-42 did not. The relationships between BP and plasma Aβ levels did not change after stratification by APOE ε4 status. Elevated BP levels were associated with increased plasma Aβ1-40 level and decreased Aβ1-42/Aβ1-40 ratio in middle-aged and old villagers. The relationship is not dependant on APOE ε4 status.