Sleep disturbance is associated with higher plasma Aβ: A population‐based cross‐sectional study

Background Growing evidence suggest that sleep disturbance is a risk factor for Alzheimer’s disease (AD). Amyloid‐β (Aβ) deposition in the brain is a main pathophysiology of AD. Although peripheral Aβ clearance is associated with brain Aβ deposition, but the relationship between sleep disturbance and plasma Aβ levels is unclear. Method This was a population‐based cross‐sectional study. A total of 1459 participants from a village in the suburbs of Xi’an, China were enrolled from January 3 to March 26, 2017. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), and good sleep quality defined as PSQI score<5 points, poor sleep quality defined as PSQI score >10. Cognitive function was assessed with the mini‐mental state examination (MMSE). Fasting venous blood was taken in the morning and plasma Aβ levels were measured by ELISA. The relationships between plasma Aβ levels and sleep quality was analyzed using multiple linear regressions. Result Among 1459 participants, 231 had poor sleep quality (15.83%). The log‐transformed Aβ 40 level had significant difference among different sleep groups (F=3.216, p =0.040). log‐transformed Aβ 40 level was higher in poor sleep quality group than that in general sleep quality group [87.17 (73.42,107.34) vs. 89.69 (74.81,125.79) pg/ml, p =0.016]. In bivariate analysis, sleep quality was negatively associated with plasma log‐transformed Aβ 40 level (β=‐0.025, p =0.011). Conclusion In the cognitively normal population, the poorer sleep quality is associated with higher plasma Aβ 40 level. These indicated that sleep disturbance may relate to peripheral Aβ clearance.