Obstructive Sleep Apnea and Cerebral Small Vessel disease in Community-based Older People: An ASPREE Imaging Substudy.

Study objectives: Obstructive sleep apnea (OSA) may increase risk of dementia. A potential pathway for this risk is through cerebral small vessel disease (CSVD). In the context of an existing randomized trial of aspirin for primary prevention, we aimed to investigate OSA's impact on CSVD imaging measures and explore whether aspirin effects these measures over 3 years that differ in the presence or absence of OSA.

Methods: A sub-study of the ASPirin in Reducing Events in the Elderly randomized placebo-controlled trial of low-dose aspirin. Community-dwelling participants aged 70 years and above, without cognitive impairment, cardiovascular disease or known OSA completed an unattended limited-channel sleep study that calculated the oxygen desaturation index and apnea-hypopnea index. At baseline and 3 years later, volumes of white matter hyperintensities (WMH) and silent brain infarctions (SBI) were measured on 1.5 Tesla brain magnetic resonance imaging, and retinal vessel calibers were calculated from retinal vascular imaging.

Results: Mild and moderate/severe OSA was detected in 48.9% and 29.9%, respectively, of the 311 participants, who had a mean age of 73.7 years (SD 3.4 years), 38.6% female. OSA of any severity did not associate with WMH volumes, SBI, nor with retinal vessel calibers at baseline, nor with change in these measures in the 277 participants with repeated measures acquired after 3 years. OSA of any severity did not interact with aspirin on change in these measures over 3 years.

Conclusion: In healthy older adults undiagnosed OSA was not associated with retinal vascular calibers and neuroimaging measures of CSVD.