Sleep disorders increase the risk of dementia, Alzheimer's disease, and cognitive decline: a meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective cohort studies
PubMed 40214959 · doi:10.1007/s11357-025-01637-2
What was done
A systematic review and meta-analysis of prospective cohort studies was conducted to evaluate the relationship between sleep disorders (obstructive sleep apnea, insomnia, restless legs syndrome, circadian rhythm disorders, and excessive daytime sleepiness) and incident cognitive decline, all-cause dementia, Alzheimer's disease (AD), or vascular dementia. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using random-effects models.
What was found
Across 39 prospective cohort studies: - All-cause dementia was significantly associated with obstructive sleep apnea (HR 1.33, 95% CI 1.09–1.61), insomnia (HR 1.36, 95% CI 1.19–1.55), and other sleep disorders (HR 1.33, 95% CI 1.24–1.43). - Alzheimer's disease risk was significantly higher with obstructive sleep apnea (HR 1.45, 95% CI 1.24–1.69) and insomnia (HR 1.49, 95% CI 1.27–1.74). - Vascular dementia was significantly associated with insomnia (HR 1.59, 95% CI 1.01–2.51), whereas the association with obstructive sleep apnea was not statistically significant (HR 1.35, 95% CI 0.99–1.84).
Why it matters
This study quantifies prospective links between specific sleep disorders and subsequent dementia subtypes, highlighting sleep health as a key target for clinical screening and dementia risk-reduction strategies.
Limits
All included studies are observational cohorts, which cannot establish causality and remain vulnerable to residual confounding and reverse causation (prodromal dementia affecting sleep architecture). The abstract does not report the total participant sample size, between-study heterogeneity, average follow-up duration, or whether sleep diagnoses relied on objective polysomnography versus self-report.
Cited by
- supports Untreated sleep apnea is an established risk factor for neurodegeneration.