High serum uric acid levels explains the negative impact of the altitude adaptation index on the brain electroencephalographic Microstate D under high-altitude hypoxic conditions

Objective: To explore the mediating role of serum uric acid (SUA) in the relationship between the acclimatization/adaptation index (AAI) and the transition probability of electroencephalographic (EEG) Microstate D within cognitive control networks under hypoxic conditions at 3,650 m. Methods: A total of 173 high-altitude residents in Lhasa were recruited. Their peripheral oxygen saturation (SpO₂), hematocrit (HCT), and SUA levels were measured, and resting-state EEG data were recorded. AAI was calculated, and the transition probability of Microstate D was analyzed. Correlation analyses and bootstrap methods were employed to examine the mediating effect of SUA. Results: AAI was significantly negatively correlated with SUA, and the maladaptive group exhibited significantly higher SUA levels. SUA mediated the relationship between AAI and the outward transition probabilities from Microstate D to Microstates A and C, but no significant mediating effect was found for inward transition probabilities. Conclusion: Under high-altitude hypoxic environments, SUA serves as a key mediator through which AAI modulates the outward transitions of Microstate D. Regulating SUA levels and enhancing AAI may play a crucial role in preserving cognitive control network function in high-altitude populations.