Melatonin for sleep and cognitive outcomes in older adults with cognitive impairment: a meta-analysis of randomised controlled trials
Abstract
OBJECTIVES
To quantify the effects of melatonin on total sleep time and global cognition, and to examine secondary outcomes (sleep efficiency, circadian markers, neuropsychiatric symptoms, depression, activities of daily living) in older adults with cognitive impairment.
DESIGN
Systematic review and meta-analysis of randomised controlled trials (PROSPERO CRD42024539227).
DATA SOURCES
PubMed, PsycINFO (via EBSCOhost), CINAHL Plus, Cochrane Library, Web of Science, to October 2024.
ELIGIBILITY CRITERIA
Randomised controlled trials (RCTs) comparing melatonin versus placebo in adults ≥65 years with mild cognitive impairment or dementia.
DATA EXTRACTION AND SYNTHESIS
Two reviewers extracted data; risk of bias was assessed by RoB 2. Random-effects models estimated Hedges' g and mean differences (MD), with Benjamini-Hochberg false discovery rate (FDR) correction for multiple outcomes. Heterogeneity assessed via I2; publication bias via Egger's test.
RESULTS
Ten RCTs (n = 516) were included. Melatonin increased total sleep time by MD +12.4 min (95% CI 8.1-16.7; P < .001; I2 = 72%; g = 0.42) and improved Mini-Mental State Examination scores by MD +1.8 points (95% CI 0.9-2.7; P = .002; I2 = 65%; g = 0.47). Neuropsychiatric symptoms decreased (g = -0.23; 95% CI -0.44 to -0.03; P = .02). Effects on sleep efficiency, circadian markers, depression and activities of daily living were small and nonsignificant.
CONCLUSIONS
Melatonin yields modest improvements in sleep duration and cognition…
How strong is the evidence?
Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 516 participants or records.
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