1006 Effect of Obstructive Sleep Apnea on the Longitudinal Change in the Glymphatic System Function

Abstract Introduction Glymphatic cerebral waste-clearance system is activated during sleep, and obstructive sleep apnea (OSA) might have impact on the long-term disruption of the glymphatic system function and the development of neurodegenerative diseases. This study investigated the longitudinal association of OSA with changes in glymphatic system function and cognitive function domains. Methods Based on a community-based prospective cohort, participants who had both baseline and 4-year follow-up polysomnography, brain MRI with diffusion tensor imaging (DTI), and comprehensive cognitive assessment data were included. At both baseline and follow-up, participants were categorized as non-OSA (apnea-hypopnea index, AHI < 5), mild OSA (5≤AHI< 15), and moderate-to-severe OSA (AHI≥15) groups. According to the longitudinal change in the OSA severity, participants were categorized as OSA-free (non-OSA at both baseline and follow-up), improved OSA, stationary OSA, and progressed OSA groups. Glymphatic system function was measured using DTI analysis along the perivascular space (DTI-ALPS) index. Results 1,110 participants (mean [SD] age, 58.0 [6.0] years; 517 [46.6%] men) were included in the final analysis. At baseline, 621 participants were categorized as non-OSA, 338 participants as mild OSA, and remaining 151 participants as moderate-to-severe OSA. At follow-up, 458 participants were categorized as OSA-free, 114 participants as improved OSA, 303 participants as stationary OSA, and 235 participants as progressed OSA. At baseline, non-OSA group exhibited higher DTI-ALPS index compared to the remaining groups (both, P< 0.001) and AHI was inversely correlated with DTI-ALPS index (R=-0.169, P< 0.001). At follow-up, the change in the DTI-ALPS index (∆DTI-ALPS) was the highest in the improved OSA group, followed by the OSA free, stationary OSA, and progressed OSA groups. ∆DTI-ALPS over 4-year was inversely correlated with ∆AHI (R=-0.171, P< 0.001 for the entire study population and R=-0.218, P< 0.001 for the population excluding OSA-free subgroup). ∆DTI-ALPS over 4-year was correlated with the changes in the visual reproduction–immediate recall (R=0.233), delayed recall (R=0.178), and recognition (R=0.188) scores (all, P< 0.001). Conclusion The changes in the OSA status has impact on the longitudinal change in the glymphatic system function and this effect might be reversible. Sustained proper management of OSA might be important in the effective prevention and management of cognitive decline. Support (if any)