Risk of Mild Cognitive Impairment in Relation to Sleep Apnea Parameters: An 8-Year Longitudinal Study in a Community-Based Cohort

초록

Introduction: obstructive sleep apnea (OSA), has been linked to cognitive impairment. However, few studies have examined how AHI severity over time relates to the development of mild cognitive impairment (MCI) in community populations. Materials and methods: A total of 1,508 cognitively intact participants (KMMSE ≥24) at baseline (2011–2014) who underwent in-home polysomnography (PSG) across three exam periods (baseline ~4-year intervals) were drawn from the Korean Genome and Epidemiology Study (KoGES) for this retrospective study. Sleep apnea parameters included overall and positional AHI, and REM and Non-REM AHI from PSG over 8 years. Participants were classified as cognitively unimpaired (CU) or Mild Cognitive Impairment (MCI) at the 2nd follow-up using the Seoul Neuropsychological Screening Battery-II (SNSB-II). Linear mixed regression estimated how 8-year trajectories of sleep parameters differed retrospectively by MCI status at the 2nd follow-up. Results: Among the sleep apnea parameters assessed via PSG, although CU group has statistically insignificant change (p=0.09), the MCI group showed a slightly steeper increase in N1% of sleep duration from 2011–2014 to 2019–2022 (β [95% CI] = 0.57 [0.18, 0.95], p = 0.004). Also, the MCI group has marginally greater increase rate of supine AHI over 8- year periods from baseline (0.87 [0.002, 1.73], p = 0.049). Other sleep parameters, including overall AHI, non-supine AHI, REM AHI, and NREM AHI, did not show differential slopes between MCI groups; however, each group presented independent increases over time (p < 0.05). In men, CU group showed a greater increasing rate in hypoxic burden index (HB) compared to MCI group (-2.64 [− 5.19, -0.09], p = 0.043). Within-group analyses indicated significant increases in both groups over 8 years (5.45[4.12, 6.78], p<0.001 and 2.81[0.63, 4.99], p=0.012, respectively). In women, N1% of sleep duration differed significantly between groups, with the MCI group showing a greater 8-year increase (0.50 [0.04, 0.96], p = 0.035). Women with MCI also had a significantly steeper increase in REM AHI (1.36 [0.08, 2.64], p = 0.037). For sleep parameters without group–time interactions, overall AHI, supine AHI, and non-supine AHI increased independently in both CU and MCI groups (p < 0.05). Unlike men, women showed an additional independent increase in NREM AHI over time in both groups (p < 0.001), without group differences. Conclusions: In this cohort, the MCI group showed modest increases in N1% of sleep duration and supine AHI, while men demonstrated no clear group differences aside from a rise in HB among CU participants. In women, however, MCI was associated with steeper increases in N1% of sleep duration and REM AHI. Given the established link between OSA and cognition, our findings suggest that rising REM AHI may contribute to elevated MCI risk, particularly in women. The significance of positional parameters further highlights posture-related vulnerability. Overall, sleep parameters in future MCI cases may diverge years before diagnosis. Acknowledgments: This study was supported by grants from the NRF funded by MSIT (RS-2024-00359247 to HJ Kim), and KDCA (2011-E71004-00 ~ 2021-E0602-01 to C Shin).