Sleep‐Disordered Breathing and Cognition in a Diverse Population

Abstract

AbstractBackgroundSleep‐disordered breathing (SDB) in older adults is associated with worse cognitive performance and dementia risk. Few studies have examined the relationship between SDB and cognition in a diverse population.MethodsWe studied 654 non‐demented participants from the Health and Aging Brain Study‐Health Disparities (HABS‐HD)‐Dormir study, with an in‐home sleep apnea assessment, a peripheral arterial tonometry‐based system (WatchPAT‐200). SDB measurements included: the respiratory event index (REI; 3% desaturation threshold) and the oxygen desaturation index (ODI; 4% threshold), split into mild (<15 events/hour) and moderate/severe (≥15 events/hour) and assessed by REM, non‐REM, and total sleep (via WatchPat algorithm). We examined three cognitive domains, defining worse cognition as negative standardized z‐scores on the Mini‐Mental Status Exam (MMSE; general cognition); the long‐delay Logical Memory and Spanish‐English Verbal Learning Test (memory); and Trails Making Test‐B and Digit Symbol Substitution (executive function). Regression analyses determined the association between SDB and cognition, adjusting for age, race, sex, education, diabetes, and hypertension.ResultsParticipants were 42.7% Non‐Hispanic White, 35.4% Mexican‐American, and 21.9% Black, averaging 66.6 (sd = 8.2) years; 65.2% were female. The average sleep duration was 6.7 (sd = 1.3) hours; 50.4% had moderate/severe REI and 24.7% had moderate/severe ODI. Compared to mild REI, participants with moderate/severe had a trend towards worse executive function (total‐REI β = ‐0.09 (95% confidence intervals ‐0.20,0.01), p = 0.08). Moderate/severe total‐REI was not associated with global cognition (β = ‐0.02 (‐0.12,0.08), p = 0.75), but moderate/severe REM‐REI was (β = ‐0.11 (‐0.20,‐0.01), p = 0.04). Moderate/severe ODI was also associated with a trend towards worse executive function (total‐ODI β = ‐0.10 (‐0.22,0.01), p = 0.08) and global cognition (total‐ODI β = ‐0.11 (‐0.21,0.01), p = 0.06) compared to mild ODI. The association was greater in non‐REM‐ODI for global cognition (β = ‐0.14 (‐0.26,‐0.02), p = 0.02) and REM‐ODI for executive function (β = ‐0.12 (‐0.22,‐0.02), p = 0.02). There were no associations between REI/ODI and memory, and no interactions with race/ethnicity or APOE4 status. Results were similar after adjusting for body mass index.ConclusionsIn an ethnically and racially diverse population, we found that SDB was prevalent and moderate/severe SDB was associated with lower general cognition and executive function. Future studies should assess the relationship between REM/non‐REM SDB and cognition, and if SDB treatment may reduce dementia risk.