Association of Midday Napping with All-Cause Mortality in Chinese Adults: A 8-Year Nationwide Cohort Study

Abstract

This study aimed to investigate the longitudinal association of estimated daytime nap duration with all-cause mortality in Chinese adults. We conceived a prospective cohort design using adult survey data of the baseline and four follow-up waves (2010–2019) from China Family Panel Studies. Cox frailty models with random intercepts for surveyed provinces were used to estimate risks of all-cause mortality associated with midday napping. Trend and subgroup analyses were also performed stratified by demographic, regional and behavioral factors. Compared with non-nappers, those who reported a long napping duration (≥60 min/day) had an increased risk of all-cause mortality, while shorter napping (<60 min) showed no association with mortality. We observed significant trends for greater risks of mortality associated with longer nap duration. Long nap-associated higher risk of all-cause mortality was seen in a group of nocturnal sleep duration ≥9 h. We identified stronger associations of long nap with mortality among adults aged over 50 years, those with lower BMI (<24 kg/m²), residents in rural regions and unregular exercisers. Long midday napping is independently associated with higher risks of all-cause mortality in Chinese adults.

Keywords:

• all-cause mortality
• adults
• midday napping
• sleep duration

Authors’ contributions

Yunquan Zhang conceived and designed the study; Lu Wang, Yiting Wang, and Hainan Shu collected and cleaned the data; Lu Wang and Yunquan Zhang drafted the original manuscript; Lu Wang, Kai Wang, and Yunquan Zhang performed the data analysis; Yaru Wang, Peixuan Zhou, Ke Wang, and Siqi Luo helped revise the manuscript. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This study was supported by Open Fund Project of Hubei Province Key Laboratory of Occupational Hazard Identification and Control (Grant No. OHIC2020Y01), Science and Technology Research Project of Hubei Provincial Department of Education (Grant No. Q20201104), and Scientific Research Project of Wuhan Health Committee (Grant No. EG20C05). We thank the China Family Panel Studies participants, staff and investigators for their contributions to the collection, collation and interpretation of data.