The effects of sleep duration on the risk of dementia incidence in short and long follow-up studies: A systematic review and meta-analysis
Bibliographic record
Abstract
Sleep duration's association with future dementia could be a cause or consequence, or both. We searched electronic databases on 14 th April 2023 for primary peer-reviewed, longitudinal studies examining the relationship between sleep duration and dementia with any follow-up duration. We meta-analysed studies examining brief (≤6 h/night) and extended sleep duration (≥9 h/night) separately and divided the studies into those with follow-up periods of less or more than 10 years. The quality of evidence was assessed using the Newcastle-Ottawa scale. 31 studies fulfilled the inclusion criteria. For brief sleep duration, a meta-analysis of short follow-up studies (≤10 years) found a 46 % increased risk of future dementia (relative risk [RR] – 1·46; 95 % Confidence Intervals [CIs] 1·48–1·77; I 2 = 88·92 %, 6 studies). Studies with long follow-ups (>10 years) did not show a significantly increased risk (RR – 1·12; 0·95–1·29; I 2 = 65·91 %; 5 studies). For extended sleep duration, a meta-analysis of short and long follow-up studies reported an increased risk of dementia (respectively RR - 2·20; 1·11–3·3; I 2 = 94·17 %; 4 studies and RR – 1·74; 1·30–2·18; I 2 = 86·56 %; 4 studies). Our findings suggest that brief sleep duration might be a prodromal symptom but not a risk factor of dementia. Extended sleep duration may be a risk factor. However, our results had high heterogeneity limiting external validity and generalisability. • • Brief sleep duration is only associated with dementia in studies with short follow-up periods (<10 years). • Extended sleep duration increased the risk of dementia in studies using short and long (≥10 years) follow-up periods. • • Heterogeneity meant that results are uncertain, and sleep duration may be associated with other risk factors. • Future research should analyse causes of sleep disturbance controlling for other risk factors and follow up of >10 years.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.022 | 0.044 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.020 | 0.055 |
| Bibliometrics | 0.009 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".