Abstract
BACKGROUND: Growing evidence indicated that to develop of atherosclerosis observed more often by people with Alzheimer's disease (AD), but the underlying mechanism is not fully clarified. Considering that amyloid-β (Aβ) deposition in the brain is the key pathophysiology of AD and plasma Aβ is closely relate to Aβ deposition in the brain, in the present study, we investigated the relationships between atherosclerosis and plasma Aβ levels. METHODS: This was a population based cross-sectional study. Patients with high risk of atherosclerosis from Qubao Village, Xi'an were underwent carotid ultrasound for assessment of atherosclerosis. Venous blood was collected on empty stomach in the morning and plasma Aβ(1-40) and Aβ(1-42) levels were measured using ELISA. Multivariate logistic regression analysis was performed to investigate the relationships between carotid atherosclerosis (CAS) and plasma Aβ levels. RESULTS: Among 344 patients with high risk of atherosclerosis, 251(73.0%) had CAS. In the univariate analysis, the plasma Aβ levels had no significant differences between CAS group and non-CAS group (Aβ(1-40): 53.07 ± 9.24 pg/ml vs. 51.67 ± 9.11pg/ml, p = 0.211; Aβ(1-42): 40.10 ± 5.57 pg/ml vs. 40.70 pg/ml ± 6.37pg/ml, p = 0.285). Multivariate logistic analysis showed that plasma Aβ levels were not associated with CAS (Aβ(1-40): OR = 1.019, 95%CI: 0.985-1.054, p = 0.270;Aβ(1-42): OR = 1.028, 95%CI: 0.980-1.079, p = 0.256) in the total study population. After stratified by hypertension, CAS was associated with plasma Aβ(1-40) positively (OR = 1.063, 95%CI: 1.007-1.122, p = 0.028) in the non-hypertension group, but not in hypertensive group. When the plasma Aβ concentrations were classified into four groups according to its quartile, the highest level of plasma Aβ(1-40) group was associated with CAS significantly (OR = 4.465, 95%CI: 1.024-19.474, p = 0.046). CONCLUSION: Among patients with high risk of atherosclerosis, CAS was associated with higher plasma Aβ(1-40) level in non-hypertension group, but not in hypertension group. These indicated that atherosclerosis is associated with plasma Aβ level, but the relationship may be confounded by hypertension.