The Interrelationship Between Sleep Disorders and Cardiovascular, Metabolic, Neurological, and Mental Health Outcomes: A Systematic Review

Abstract

Background: Sleep disorders, including insomnia and obstructive sleep apnea (OSA), and abnormal sleep duration are highly prevalent and have been independently associated with adverse outcomes across multiple organ systems. Although the cardiovascular, metabolic, neurological, and psychiatric correlates of disordered sleep have each been extensively studied in isolation, the extent to which these four domains share common risk gradients, effect sizes, and underlying mechanisms has not been comprehensively synthesised within a single review.
Objective: To systematically review the published evidence describing the interrelationship between sleep disorders (insomnia, OSA, and short/long sleep duration) and cardiovascular, metabolic, neurological, and mental health outcomes.
Methods: Electronic databases were searched for systematic reviews, meta-analyses, and large prospective cohort studies quantifying the association between a defined sleep disorder or sleep-duration exposure and incident cardiovascular disease, type 2 diabetes or obesity, dementia or cognitive decline, or depression/anxiety. Two reviewers independently screened records, extracted data, and appraised study quality. Findings were synthesised narratively across the four outcome domains given substantial heterogeneity in exposure definition, population, and outcome ascertainment.
Results: Fourteen studies, including nine meta-analyses collectively representing several million participants and five large landmark cohort studies, met the inclusion criteria. Short and long sleep duration were each associated with increased cardiovascular risk in a U-shaped or J-shaped pattern, with short sleep associated with coronary heart disease (relative risk [RR] 1.48) and long sleep associated with stroke (RR 1.65). Obstructive sleep apnea was independently associated with stroke or death (hazard ratio [HR] 1.97) and fatal/non-fatal cardiovascular events (odds ratio [OR] 2.87–3.17). Both short and long sleep duration were associated with incident type 2 diabetes (RR 1.09 and 1.14 per 1-hour deviation from 7 hours) and obesity. Sleep disturbances, insomnia, and OSA were each independently associated with incident dementia and Alzheimer's disease (HR range 1.29–1.49), and insomnia was a robust predictor of incident depression (OR 2.60–2.83) and anxiety disorders (OR 3.23).
Conclusions: Sleep disorders and abnormal sleep duration are consistently and independently associated with adverse cardiovascular, metabolic, neurological, and mental health outcomes, with effect sizes of comparable and clinically meaningful magnitude across all four domains. These findings support the integration of routine sleep assessment into cardiovascular, metabolic, neurological, and psychiatric risk evaluation, and highlight sleep health as a modifiable, cross-cutting target for multisystem disease prevention.