Table 1.
Summary of major findings on the relationship between sleep duration and neurocognitive disorders
| Study | Study type | Sleep measures | Outcomes | Main findings |
|---|---|---|---|---|
| Xu et al, 20201 | Meta-analysis of 17 longitudinal prospective cohort studies | Nocturnal sleep duration* | Cognitive impairment, major NCD, AD, VD | V-shaped association between sleep duration and cognitive decline, major NCD, and AD; significantly increased risk associated with habitual nighttime sleep <4 and >10 hours in a dose-response manner |
| Wu et al, 20212 | Prospective cohort study, N = 16,948 | Total sleep duration* | Cognitive impairment | U-shaped association between sleep duration and MMSE score; change in sleep duration (increased/decreased) associated with increased odds of cognitive impairment |
| Ohara et al, 20183 | Prospective cohort study, N = 1517 | Total sleep duration* | Major NCD, VD, AD | Increased risk for major NCD, AD, and VD associated with sleep duration <5, 8–9.9, and >10 hours |
| Virta et al, 20134 | Prospective cohort study, N = 2336 | Nocturnal and total sleep duration* | Cognitive impairment, AD | Habitual short (<7 hours) and long (>8 hours) sleep duration starting in midlife associated with cognitive impairment; long sleep associated with increased risk for AD |
| Bokenberger et al, 20175 | Register-based cohort study, N = 11,247 | TIB, rise time, and bedtime* | Major NCD | U-shaped association for TIB (<6, >9 hours) and incident major NCD; short TIB is a risk factor for major NCD |
| Gildner et al, 20146 | Stratified multistage cluster, N = 34,203 | Nocturnal sleep duration* | Cognitive impairment | Short (<6 hours) and long (>9 hours) sleep associated with lower cognitive performance |
| Robbins et al, 20217 | Longitudinal cohort study, N = 2812 | Nocturnal sleep duration* | Major NCD | Short (<5 hours) sleep associated with a twofold increased risk for major NCD |
| Chen et al, 20168 | Prospective cohort study, N = 7444 | Nocturnal sleep duration* | Minor and major NCD | Short (<6 hours) and long (>8 hours) sleep associated with increased risk for NCD; short sleep resulted in 30% increased risk after adjustment for confounders |
| Sabia et al, 20219 | Longitudinal prospective cohort study, N = 8321 | Nocturnal sleep duration* accelerometer | Major NCD | Short sleep (<6 hours) associated with a greater risk for incident major NCD in adults aged 50–65 preceding average onset of major NCD (75 years) |
| Ferrie et al, 201110 | Longitudinal prospective cohort study, N = 10,308 | Nocturnal sleep duration* accelerometer | Cognitive impairment | V-shaped association between sleep duration and cognitive impairment; sleep-related changes in cognitive decline equivalent to 4–7 years of aging |
| Lu et al, 201811 | Population-based cohort study, N = 7422 | Total sleep duration* | Major NCD | No association between short sleep duration and incident major NCD |
| Lysen et al, 201812 | Prospective population-based study, N = 4835 | Nocturnal sleep duration* | Major NCD | No association between short sleep duration and incident major NCD |
Conclusions about short and long sleep are in comparison to recommended optimal sleep (7 hours). AD indicates Alzheimer’s disease; MMSE, Mini-Mental State Exam; NCD, neurocognitive disorders; TIB, time in bed; VD, vascular dementia.
*
Self-reported.