[Characteristics of white matter hyperintensities in young and middle-aged male patients with obstructive sleep apnea and its impact on cognitive function].

Objective: To explore the characteristics of white matter hyperintensities (WMH) in young and middle-aged male patients with obstructive sleep apnea (OSA) who did not have cardiovascular and cerebrovascular diseases, and its impact on cognitive function. Methods: This was a cross-sectional study. Patients who visited the sleep center of the Second Affiliated Hospital of Soochow University due to snoring between June 2021 and June 2023 were prospectively selected. All patients meeting the inclusion criteria underwent polysomnography (PSG) monitoring, while cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA) and the Cambridge Neuropsychological Test Automated Battery (CANTAB). All subjects underwent Brain magnetic resonance imaging (MRI), and the Fazekas visual rating scale was used to assess the severity of WMH. Subjects were divided into a control group (AHI≤15/h) and an OSA group (AHI>15/h) based on the apnea-hypopnea index (AHI), and the above indicators were compared between the two groups. Spearman correlation analysis was conducted to investigate the relationship between WMH and cognitive function. A logistic regression model was used to analyze the risk factors associated with WMH occurrence. Results: A total of 104 subjects were enrolled, all male, 48 in the control group and 56 in the OSA group. Comparisons of PSG parameters indicated that the OSA group had a higher AHI, percentage of non-rapid eye movement sleep stage 1 and 2 in total sleep time (N1%+N2%), oxygen desaturation index (ODI), and percentage of total sleep time with pulse oxygen saturation below 90% (TS90) (all P<0.05). In contrast, the percentage of Non-Rapid Eye Movement Sleep Stage 3 in total sleep time (N3%) and the percentage of Rapid Eye Movement Sleep in total sleep time (REM%), and the Minimum pulse oxygen saturation (MinSpO₂) were lower (all P<0.05). Cognitive test comparisons indicated that the OSA group had lower total MoCA scores, and lower scores on sub-items such as visuospatial, executive function and delayed recall compared to the control group. In the CANTAB, the average reaction time for motor screening task(MOT), the delayed recognition response time for pattern recognition memory(PRM), and the total completion time for spatial working memory(SWM) were all longer (all P<0.05). MRI imaging revealed that the incidence of cerebral WMH and the Fazekas score were higher in the OSA group compared to the control group, and that deep white matter hyperintensities (DWMH) were most common in the frontal lobe. The Fazekas grade of the subjects was correlated positively with the MOT reaction time (r=0.25, P=0.026) but negatively with the immediate recognition accuracy of PRM (r=-0.36, P=0.002). Regression results indicated that, increasing age was an independent risk factor for the occurrence of WMH in young and middle-aged OSA patients (OR=1.120, 95%CI: 1.038-1.210, P=0.004), while an increase in REM% was a protective factor (OR=0.882, 95%CI: 0.801-0.901, P=0.011). Conclusions: A significant proportion of young and middle-aged male OSA patients exhibited WMH, and there was a correlation between WMH and cognitive decline. Increasing age was an independent risk factor for WMH occurrence in young and middle-aged male OSA patients, while a higher proportion of REM sleep was an independent protective factor.