A Prospective Study of Sleep Duration and Mortality Risk in Women
Bibliographic record
Abstract
STUDY OBJECTIVES: It is commonly believed that 8 hours of sleep per night is optimal for good health. However, recent studies suggest the risk of death is lower in those sleeping 7 hours. We prospectively examined the association between sleep duration and mortality in women to better understand the effect of sleep duration on health. DESIGN: Prospective observational study. SETTING: Community-based. PARTICIPANTS: Women in the Nurses Health Study who answered a mailed questionnaire asking about sleep duration in 1986. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Vital status was ascertained through questionnaires, contact with next of kin, and the National Death Index. During the 14 years of this study (1986-2000), 5409 deaths occurred in the 82,969 women who responded to the initial questionnaire. Mortality risk was lowest among nurses reporting 7 hours of sleep per night. After adjusting for age, smoking, alcohol, exercise, depression, snoring, obesity, and history of cancer and cardiovascular disease, sleeping less than 6 hours or more than 7 hours remained associated with an increased risk of death. The relative mortality risk for sleeping 5 hours or less was 1.15 (95% confidence interval [CI], 1.02-1.29) for 6 hours, 1.01 (95% CI, 0.94-1.08), for 7 hours, 1.00 (reference group), for 8 hours, 1.12 (95% CI, 1.05-1.20), and for 9 or more hours 1.42 (95% CI, 1.27-1.58). CONCLUSIONS: These results confirm previous findings that mortality risk in women is lowest among those sleeping 6 to 7 hours. Further research is needed to understand the mechanisms by which short and long sleep times can affect health.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".