0468 SLEEP-DISORDERED BREATHING, COGNITIVE FUNCTION AND RISK OF COGNITIVE DECLINE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Introduction: Growing evidence suggests an association between sleep-disordered breathing (SDB) and cognitive decline in the elderly. However, existing population-based studies have been conflicting and few have considered differential effect on cognitive domains. This meta-analysis aims to provide a quantitative synthesis of the relationship between SDB, cognitive function and risk of cognitive decline or impairment. Methods: We performed a systematic search of publications (in English) using PubMed, EMBASE and PsychINFO. We included cross-sectional and prospective studies with at least 200 participants with an average age of ≥ 40 years, defined SDB by apnea-hypopnea index (AHI) or clinical diagnosis, and incorporated cognitive outcomes based on standard tests or diagnosis of cognitive impairment. We extracted and pooled adjusted risk ratios from prospective studies and standard mean differences (SMD) from cross-sectional studies, using random-effect models. We focused on three cognitive domains: global cognition, executive function and delayed memory. We tested heterogeneity between studies using the I2 statistics, and used Egger test and funnel plot asymmetry to evaluate publication bias. Results: We included 14 studies, of which six were prospective, and covered a total of 4,288,419 men and women. Pooled analysis of the six prospective studies indicated that those with diagnosed sleep apnea or an AHI of ≥15 were 26% (RR= 1.26; 95% CI: 1.05-1.50) more likely to develop cognitive decline or dementia, with no evidence of publication bias (p=0.74) but heterogeneity between studies (p=0.04). After removing one study that introduced significant heterogeneity, the pooled RR was 1.35 (95% CI: 1.11-1.65). Pooled analysis of seven cross-sectional studies suggested that those with SDB had significantly worse executive function (SMD=-0.05; 95%CI: -0.09-0.00), with no evidence of heterogeneity (p=0.31) or publication bias (p=0.65). SDB was not associated with global cognition or memory. Conclusion: SDB is associated with an increased risk of cognitive decline or dementia. There is a cross-sectional association between SDB and executive function but not with other cognitive domains. Further studies are required to determine mechanisms linking these common conditions.