Abstract
Background The relationship between obstructive sleep apnoea (OSA) and cognitive decline remains controversial, especially in the elderly population. We used data from the HypnoLaus study to assess associations between OSA and longitudinal cognitive changes in a sample of community-dwelling elderly individuals.
Methods We studied associations between polysomnographic OSA parameters (of breathing/hypoxaemia and sleep fragmentation) and cognitive changes over a 5-year period, after adjustment for potential confounders. The primary outcome was the annual change in cognitive scores. The moderating effects of age, sex and apolipoprotein E4 (ApoE4) status were also examined.
Results 358 elderly individuals without dementia were included (71.0±4.2 years; men 42.5%). A lower mean oxygen saturation during sleep was associated with a steeper decline in Mini-Mental State Examination (B=-0.12, p=0.004), Stroop test condition 1 (B=0.53, p=0.002) and delayed free recall of the Free and Cued Selective Reminding Test (B=-0.05, p=0.008). A longer time spent asleep with an oxygen saturation <90% was associated with a steeper decline in Stroop test condition 1 (B=0.47, p=0.006). Moderation analysis showed that apnoea-hypopnoea index and oxygen desaturation index were associated with a steeper decline in global cognitive function, processing speed and executive function only in older participants, men and ApoE4 carriers.
Conclusions Our results provide evidence of the contribution of OSA and nocturnal hypoxaemia to cognitive decline in the elderly population.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflicts of interest: R. Heinzer is member of the medical advisory board of Dreem and Nightbalance (Philips) and received speaker's fees or honorarium from ResMed, Philips, Jazz, and Inspire. Other authors have nothing to disclose.
- Received August 18, 2022.
- Accepted January 29, 2023.
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