Objective: Sleep-related breathing disorders (SRBD) have shown to cause worsened cognitive impairment among people with dementia. Therefore, we conducted the first meta-analysis to estimate the prevalence of SRBD among people with dementia. Methods: Comprehensive searches were conducted in Embase, Ovid-MEDLINE, PubMed, PsycINFO, Scopus, Web of Science, and CINAHL. The generalized linear mixed model (GLMM) was used for the pooled prevalence analysis and heterogeneity using I2 test and Cochran's Q-statistic in R-software. Study quality was assessed by Hoy's risk of bias assessment tool. Overall, 20 studies from 1282 studies were included with 1461 participants. Results: The pooled prevalence of SRBD among dementia was 59% (95%CI: 44%–73%) with 55% (95%CI: 34%–74%) for obstructive sleep apnea (OSA), 49% (95%CI: 25%–73%) for unspecified SRBD, and 11% (95%CI: 5%–21%) for central sleep apnea (CSA). Regarding dementia subtypes, the prevalence of SRBD was 89% (95%CI: 61%–97%) for Alzheimer's dementia, 56% (95%CI: 48%–63%) for Parkinson's and Idiopathic Parkinson's dementia, and 16% (95%CI: 8%–30%) for Huntington's dementia. Significant moderator variables were male, body mass index, larger waist and hip circumference, waist-hip ratio, and comorbidities including hypertension, dyslipidemia, renal disease, diabetes, heart disease, and stroke. Conclusions: There is considerable high prevalence of SRBD among dementia people, with OSA and unspecified SRBD being fivefold higher than CSA. Regarding dementia subtypes, Parkinson's and Idiopathic Parkinson's, and Alzheimer's dementia had four to sixfold increased risk of presenting with SRBD than Huntington's dementia. Therefore, assessment and management of SRBD in Alzheimer's, and Parkinson's and Idiopathic Parkinson's dementia deserves more attention in future research.
