Sleep quality mediates the relationship between systemic inflammation and neurocognitive performance

Area of Science:

• Neuroscience
• Immunology
• Sleep Science

Background:

• Systemic inflammation, marked by pro-inflammatory cytokines, is linked to cognitive decline.
• Sleep quality is a critical factor influencing both inflammation and neurocognitive health.
• Understanding the interplay between inflammation, sleep, and cognition is vital for addressing cognitive impairment.

Purpose of the Study:

• To investigate the relationship between systemic inflammation markers, subjective sleep quality, and neurocognitive performance in healthy adults.
• To explore the mediating role of sleep quality in the association between inflammation and cognition.
• To examine the moderating effect of IL-12 on the relationship between IL-18, sleep quality, and cognitive function.

Main Methods:

• Serum levels of IL-6, IL-12, IL-18, TNF-α, and IFN-γ were measured in 252 healthy adults.
• Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index.
• Neurocognitive performance was evaluated using the Hong Kong Montreal Cognitive Assessment.

Main Results:

• Neurocognitive performance was negatively associated with IL-18 levels (p=0.046) and positively associated with sleep quality (p=0.006).
• Sleep quality mediated the IL-18 and neurocognitive performance link, moderated by IL-12 levels.
• Good sleep quality buffered IL-18's negative cognitive effects when IL-12 was low; poor sleep quality mediated the association when IL-12 was high.

Conclusions:

• Systemic inflammation, particularly IL-18, negatively affects neurocognitive performance.
• Sleep quality, modulated by the IL-18/IL-12 axis, plays a crucial role in cognitive changes.
• These findings offer insights into mechanisms of cognitive impairment and potential preventive strategies.