Hypertension moderates the relationship between plasma beta-amyloid and cognitive impairment: a cross-sectional study in Xi'an, China.

Abstract

Background: Plasma beta-amyloid (Aβ) are important biomarkers for Alzheimer's disease and cognitive impairment (CI), but results are controversial. It remains unclear whether hypertension modulates their relationship. This cross-sectional study investigates whether hypertension moderates the relationship between plasma Aβ and cognitive impairment (CI).

Methods: This cross-sectional study included 1488 subjects ≥ 40 years from rural areas of northwestern China. CI was defined as a Mini-Mental State Examination score lower than the cutoff. Firstly, plasma Aβ₄₀, Aβ₄₂, Aβ₄₂/Aβ₄₀ were analyzed as restricted cubic spline. Then, categories of combined plasma Aβ were created by making bisection of plasma Aβ according to average and combining them as L-Aβ₄₀ and L-Aβ₄₂, H-Aβ₄₀ and L-Aβ₄₂, L-Aβ₄₀ and H-Aβ₄₂, H-Aβ₄₀ and H-Aβ₄₂. Decreased plasma Aβ₄₀ was defined as < 25th percentile. Multivariate logistic regression examined the relationship between plasma Aβ and CI in total population, the hypertension subgroup and the non-hypertension subgroup.

Results: 737 participants (49.5%) had hypertension and 189 participants (12.7%) had CI. Simultaneously elevated plasma Aβ₄₀ and Aβ₄₂ was associated with CI in hypertension (H-Aβ₄₀ and H-Aβ₄₂ vs. L-Aβ₄₀ and L-Aβ₄₂, 21.1% vs.10.7%, P = 0.033; OR = 1.984 [95% CI, 1.067-3.691], P = 0.030) but not in the non-hypertension. Decreased plasma Aβ₄₀ was associated with CI in the non-hypertension (14.9% vs. 9.2%, P = 0.026; OR = 1.728 [95% CI, 1.018-2.931], P = 0.043) but not in the hypertension.

Conclusion: Hypertension is an important modulator in the relationship between plasma Aβ and CI. Simultaneously elevated plasma Aβ₄₀ and Aβ₄₂ in the hypertension, and decreased plasma Aβ₄₀ in the non-hypertension, may be risk factors for CI. These findings emphasize the need to consider hypertension in CI detection.