Higher brain amyloid burdens in patients with severe obstructive sleep apnea: A pilot PET imaging study

Background: Obstructive sleep apnea (OSA) has been linked to an increased risk of dementia. Few studies have crosssectionally examined whether clinically-confirmed OSA is associated with a higher brain amyloid burden. Objective: This compared brain amyloid burden in individuals with untreated OSA and healthy controls, and explored associations between amyloid burden and polysomnographic and subjective measures of sleep, demographics, and mood. Methods: Thirty-four individuals with OSA (mean age 57.5±4.1 y; 19 males) and 12 controls (mean age 58.5±4.2 y; 6 males) underwent a clinical polysomnogram and a 11C-PiB positron emission tomography (PET) scan to quantify amyloid burden. Results: Amyloid burden was elevated in the OSA group relative to controls, and was significantly higher in those with severe OSA relative to mild/moderate OSA. Higher amyloid burden was associated with a higher Non-REM apnea hypopnea index, nocturnal oxygen nadir, and less time spent in stage N3 sleep, when controlling for age. Conclusion: Severe OSA is associated with a modest elevation of brain amyloid, the significance of which should be further investigated to explore the implications for dementia risk.