RESUMO
BACKGROUND AND OBJECTIVES: Alzheimer's disease (AD) and other forms of dementia represent a rising global public health crisis. As effective treatments to prevent, cure, or slow progression of dementia are unavailable, identification of treatable risk factors that increase dementia risk, such as obstructive sleep apnea (OSA), could offer promising means to modify dementia occurrence or severity. Here we systematically reviewed the impact of positive airway pressure (PAP) therapy on incidence of cognitive disorders and cognitive decline among middle-aged and older adults with OSA. METHODS: A systematic search of MEDLINE, EMBASE, Scopus, and CINAHL was performed prior to May 2021 to identify articles that focused on associations between PAP therapy use and cognitive disorders. We included studies that examined the effects of PAP treatment on: 1) incidence of cognitive disorders among individuals ages 40 or older diagnosed with OSA; and 2) progression of cognitive decline among people with pre-existing cognitive disorders and OSA. RESULTS: Eleven studies (three clinical trials and eight observational studies) were identified. In these studies, 96% participants had OSA (n= 60,840) and n=5,826 had baseline cognitive impairment (mild cognitive impairment [MCI] or AD). Of all study participants, n=43,973 obtained PAP therapy, and n=16,397 were untreated or in a placebo group. Most studies reported a protective effect of PAP therapy on MCI and AD incidence, e.g., delayed age at MCI onset, reduced MCI or AD incidence, slower cognitive decline, or progression to AD. DISCUSSION: These findings suggest a role of OSA as a modifiable risk factor for cognitive decline. The burden of cognitive disorders on aging adults and their families calls for identification of modifiable risk factors to alleviate their impact among aging adults and their families. Future research should build on this review and focus on PAP interventions as a potential means to alleviate the incidence of cognitive disorders and cognitive decline, particularly among ethnoracial minority groups who have been underrepresented and under-investigated in the extant literature.