title: Sleep duration and timing in relation to osteoporosis in an elderly Chinese population: a cross-sectional analysis in the Dongfeng-Tongji cohort study.
abstract: This population-based cross-sectional study in an older Chinese population shows a link between sleep duration, sleep timing, and osteoporosis risk, suggesting that sleep may have a role in osteoporosis development. These findings may help to identify contributing mechanisms and provide new opportunities for sleep-focused interventions to prevent osteoporosis.
  
  
  BACKGROUND
  Accumulated evidence suggests that sleep pattern disruption may lead to alterations in physiology, potentially triggering the development of osteoporosis. The present study sought to examine whether sleep duration or sleep timing is associated with osteoporosis.
  
  
  METHODS
  A total of 31,769 participants (aged 45-86 years) were recruited from the Dongfeng-Tongji cohort study. All participants completed questionnaires and medical examinations and provided blood samples. The presence of osteoporosis was determined using calcaneal quantitative ultrasonography. Logistic regression models were used to evaluate the association of sleep duration and timing with osteoporosis, after adjusting for potential confounders.
  
  
  RESULTS
  The prevalence of osteoporosis was 14.2 % in men and 23.9 % in women. After controlling for potential confounders, the adjusted odds ratio (OR) [95 % confidence interval (CI)] for osteoporosis comparing sleep duration of 9 h or longer with the reference (7-8 h) was 1.40 (1.22-1.62) in men and 1.20 (1.07-1.33) in women. Men with early sleep timing (going to sleep before 21:00 h) were more likely to have osteoporosis (OR, 1.43; 95 % CI, 1.16-1.78) than those with normal sleep timing (going to sleep between 21:00 and 23:00 h). In the interaction analysis, participants with long sleep duration and early sleep timing had the highest risk of osteoporosis both in men (OR, 1.79; 95 % CI, 1.48-2.16) and women (OR, 1.41; 95 % CI, 1.19-1.66).
  
  
  CONCLUSIONS
  Long sleep duration (≥9 h) and early sleep timing were independently and interactively associated with an increased risk of osteoporosis in this older Chinese population.
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Tian
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: S
authors.initials: S
authors.lastname: Yang
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: L
authors.initials: L
authors.lastname: Song
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China.
authors.forename: C
authors.initials: C
authors.lastname: Mandiwa
authors.affiliation: Dongfeng General Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Social Medicine, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liang
authors.affiliation: MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. wangyoujie@mails.tjmu.edu.cn.|Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, 430030, Hubei, China. wangyoujie@mails.tjmu.edu.cn.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D013997:Time Factors
keywords: China; Osteoporosis; Sleep duration; Sleep timing