Exploration of Plasma Biomarkers of Neurodegeneration in Obstructive Sleep Apnea—Related Mild Cognitive Impairment

ABSTRACT Objectives Obstructive sleep apnea (OSA) is currently viewed as a chronic, multisystem condition associated with an increased risk of cognitive impairment, especially mild cognitive impairment (MCI). As biomarkers of neurodegeneration, we evaluated whether neurofilament light (NfL), amyloid‐β 42(Aβ‐42) and amyloid‐β 40 (Aβ‐40) can be used to indicate MCI in OSA. Design A cross‐sectional study. Setting Single‐centre trial at tertiary medical institutions. Participants A total of 153 newly diagnosed subjects with OSA. Main Outcomes Measures All participants completed polysomnography, neuropsychological assessments, and plasma biomarkers of neurodegeneration detection, including NfL, Aβ‐42 and Aβ‐40. Results Compared to the cognitively normal group, only the levels of plasma NfL were increased in the MCI group. The plasma NfL levels were associated with an increased risk of cognitive impairment in OSA patients after adjusting for age, gender, body mass index, and education year. Plasma NfL outperformed other biomarkers in differentiating MCI from normal cognition (area under the ROC curve AUC = 0.829). Plasma NfL, in combination with conventional factors (age, body mass index, smoking, alcohol consumption, diabetes mellitus, hypertension, history of snoring, history of apneic episodes and time ratio of SaO 2 < 90%) yielded an AUC of 0.907 for differentiating between MCI and normal cognition. Conclusions These findings indicate that the plasma NfL was increased in OSA patients with cognitive impairment. Furthermore, plasma NfL appears to be superior to plasma Aβ for identifying MCI in OSA and holds potential as an objective biomarker associated with MCI in these patients.