Background Previous studies revealed inconsistent findings regarding the association between sleep duration and all-cause and disease-specific mortality. This study aimed to clarify the association of sleep duration with mortality using a large population-based prospective cohort study from the USA.
Methods We used data from the National Health Interview Survey (2004–2014) linked to National Death Index records to 31 December 2015. A total of 284 754 participants aged ≥18 years were included. Self-reported sleep duration (average time slept in a 24-hour period) was categorised into seven groups: ≤4 hours, 5 hours, 6 hours, 7 hours (reference), 8 hours, 9 hours and ≥10 hours. Study outcomes included all-cause, cardiovascular disease-specific and cancer-specific mortality. Cox proportional hazards models were used to examine the association between sleep duration and mortality.
Results During a median follow-up of 5.25 years, we identified 20 872 deaths, of which 4 129 were cardiovascular disease-related and 5 217 were cancer-related. Compared with 7 hours/day of sleep, both short and long sleep durations were associated with an increased risk of all-cause mortality (≤4 hours: HR=1.46, 95% CI=1.33–1.61; 5 hours: HR=1.22, 95% CI=1.13–1.32; 6 hours: HR=1.10, 95% CI=1.05–1.17; 8 hours: HR=1.22, 95% CI=1.17–1.28; 9 hours: HR=1.41, 95% CI=1.31–1.51; ≥10 hours: HR=2.00, 95% CI=1.88–2.13). Similar results were observed for cardiovascular disease-specific and cancer-specific mortality.
Conclusions Our study indicates that both short (≤6 hours/day) and long (≥8 hours/day) sleep durations increase the risk of mortality compared with sleep of 7 hours/day. A normal sleep duration (about 7 hours) every day is recommended for health benefits.
- cohort studies
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Contributors BX was responsible for the conception and design of the study. BX analysed the data. LY drafted the manuscript. CGM and MZ critically revised the manuscript for important intellectual content. All authors approve the final version of the manuscript. BX is the guarantor for the study.
Funding This work was supported by the Youth Team of Humanistic and Social Science of Shandong University and the Innovation Team of ‘Climbing’ Program of Shandong University. The sponsor had no role in the study design, survey process, data analysis, or manuscript preparation.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethical approval is obtained from the NCHS Ethics Review Board.
Data availability statement The National Health Interview Survey (NHIS) is a public data repository that is freely available online (https://www.cdc.gov/nchs/nhis/index.htm) and can be used by bio-statistician following the instructions provided by the US Centers for Disease Control and Prevention.
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