Patients With OSAHS at Higher Risk of Alzheimer Disease Biomarkers, Cognitive Decline

Patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) had significantly higher Alzheimer disease (AD) biomarkers than those without the condition based on plasma concentrations, which may explain the occurrence of cognitive decline in these populations, according to study findings published in European Archives of Oto-Rhino-Laryngology.

OSAHS, a common cause of breathing-related sleep disorder, is characterized by an upper airway collapse during sleep that causes repetitive episodes of airflow reduction (hypopnea) or cessation (apnea). As study authors note, patients with OSAHS are often subject to symptoms such as decreased cognitive function and excessive daytime sleepiness (EDS), in which cognitive decline has been associated with AD biomarkers.

Researchers sought to uncover whether these biomarkers may be more prominent in those with OSAHS and if the disorder then intensified related symptoms of EDS and cognitive decline. The study authors compared the plasma levels of a Chinese patient cohort of those requiring hospitalization for severe OSAHS (n = 35) and normal control patients (n = 16) selected from West China Hospital.

In all 51 subjects, ELISA measured the presence of AD biomarkers Aβ40, Aβ42, t-tau, and p-tau. Additionally, researchers conducted a correlation analysis of disease-related indicators to examine the effect of OSAHS on related symptoms, and a univariate analysis via logistic regression model to analyze risk factors of OSAHS.

In the study findings, plasma of patients with OSAHS compared with controls exhibited significantly higher mean (SD) levels of AD biomarkers Aβ40 (29.24 [32.52] vs 13.18 [10.78]; P = .049), t-tau (11.88  [7.05] vs 7.64 [4.17]; P  = .037), and p-tau (26.31 [14.41] vs 17.34 [9.12]; P =  .027). All 4 AD biomarkers (Aβ40, Aβ42, t-tau, p-tau) were found to have significant negative correlations with mean oxygen saturation, low oxygen saturation, and Mini-Mental State examination scale scores, stressing the potential effect of increased biomarker levels on severity of EDS and cognitive function.

As AD biomarkers were also positively correlated with the oxygen desaturation index and scores from the Epworth Sleepiness Scale, study authors noted that the particular prominence of biomarkers t-tau and p-tau can serve as new risk factors for OSAHS.

“The AD biomarkers deposited in plasma may also cause the decline of patients’ cognitive function, increased daytime sleepiness and accelerate the progression of obstructive sleep apnea—hypopnea syndrome,” they wrote.

The potential significance of AD biomarkers on severity of the related OSAHS symptoms EDS and cognitive functioning could prove beneficial in determining the risk of affected individuals. As those with EDS have been shown in a prior study to be 2.5 times more likely to be involved in occupational accidents, screening patients and providing necessary interventions may assist in reducing these risks.

Reference

Kong W, Zheng Y, Xu W, et al. Biomarkers of Alzheimer’s disease in severe obstructive sleep apnea—hypopnea syndrome in the Chinese population [published online April 17, 2020]. Eur Arch Otorhinolaryngol. doi: 10.1007/s00405-020-05948-2.