Sleep apnoea, cognition and aspirin's effects in healthy older people: an ASPREE substudy.

IMPORTANCE

Obstructive sleep apnoea (OSA) may increase the risk of dementia; however, studies have reported variable findings. We investigated if undiagnosed OSA in healthy older adults is associated with cognitive decline, and whether low-dose aspirin could attenuate this.

METHODS

This was conducted as a substudy of the ASPirin in Reducing Events in the Elderly study. Participants were aged 70 years and above, free of dementia, cardiovascular disease and known OSA. A limited channel home sleep study calculated the oxygen desaturation index. Participants were randomised to daily aspirin 100 mg or placebo. Outcomes were the association of OSA, and the interaction of aspirin with OSA, with change in the Modified Mini-Mental State examination (3MS), a test of global cognition, over 3 years. Secondary outcomes were changes in domain-specific cognitive tests. Analyses were adjusted for relevant demographic, lifestyle and cardiometabolic factors.

RESULTS

Mild OSA, detected in 630 (49.0%) participants, and moderate/severe OSA, detected in 405 (31.5%) participants, were associated with lower 3MS scores over 3 years (mild OSA: β -0.58, 95% CI -1.15 to -0.00, p=0.049; moderate/severe OSA: β -0.69, 95% CI -1.32 to -0.05, p=0.035), compared to the 250 (19.5%) participants without OSA. No associations of OSA with decline in domain-specific cognitive tests were observed. Interaction terms were not significant for the effects of aspirin with OSA on change in any cognitive test score.

CONCLUSIONS

OSA was associated with a small decline in global cognition over 3 years in this healthy older cohort. This decline was not attenuated by aspirin.