6 The Role of CPAP Treatment on Associations Between Obstructive Sleep Apnea and Cognition Among Black and White Older Adults

Abstract

Objective:Obstructive sleep apnea (OSA) may be a modifiable risk factor for late-life cognitive impairment. We previously demonstrated that non-Hispanic Black older adults are less likely to be diagnosed with OSA despite having equal or greater health risk for OSA compared to non-Hispanic White older adults, and this disparity in diagnosis was strongest among individuals with lower education. Here, we aimed to determine 1) whether there are racial differences in continuous positive airway pressure (CPAP) treatment, 2) how CPAP treatment may influence OSA-cognition associations, and 3) whether CPAP differentially influences OSA-cognition associations across racial groups.Participants and Methods:Cross-sectional data were obtained from 424 socioeconomically diverse community-dwelling adults ages 55-83 (63.4±3.2 years, 41.7% male, 53.5% Black) from the Michigan Cognitive Aging Project. Physician-diagnosed OSA and current CPAP use were self-reported. Global cognition was operationalized as a composite of five factor scores derived from a comprehensive neuropsychological battery. Racial group differences were investigated with chi-square and Fisher’s exact tests with statistical significance set at the .05 level. Associations between OSA and cognition (adjusted for age, gender, race, and years of education) were investigated with linear regressions. Subsequent models isolated effects of uncontrolled OSA by excluding individuals using CPAP. Racial differences in OSA-cognition associations were investigated with race-stratified models.Results:Fewer Black participants (9.2%) reported diagnosed OSA compared to White participants (12.3%; x2 (1, N=424) =5.314, p=.021, cp=.112). In the whole sample, 47.3% of participants with diagnosed OSA reported CPAP use, and this proportion did not differ across race (x2 [1, N=86] =.048, p=.826). In the whole sample, OSA diagnosis was only associated with cognition when CPAP users were excluded (excluding CPAP users: ß=-.085, SE=.037, p=.024; including CPAP users: ß=-.067, SE=.036, p=.062). In race-stratified models, diagnosed OSA was only associated with cognition among Black participants, and this association was stronger when CPAP users were excluded (excluding CPAP users: ß=-.142, SE=.060, p=.018; including CPAP users: ß=-.126, SE=.058, p=.030). Diagnosed OSA was not associated with cognition among White participants, irrespective of whether CPAP users were included (excluding CPAP users: ß=-.084,SE=.068, p=.215; including CPAP users: ß=-.056, SE=.064, p=.378).Conclusions:Our findings support CPAP treatment as a potential intervention to mitigate late-life cognitive impairment among those with OSA. Despite being less likely to receive a diagnosis of OSA, Black older adults were equally likely to engage in CPAP treatment as White older adults when diagnosed. The detrimental impact of OSA on cognition may be more salient among Black older adults, which may reflect racial disparities in cardiovascular risk and/or resources that promote cognitive reserve. However, CPAP appears to be an effective treatment to reduce OSA-related cognitive impairment for Black older adults, highlighting the critical importance of diagnosis and treatment in this group. Intervention efforts that abate racial inequalities in access to quality healthcare in order to facilitate acquisition of a formal OSA diagnosis and CPAP treatment may help to reduce preventable cognitive health disparities among older adults.