title: Longer Sleep Duration and Midday Napping Are Associated with a Higher Risk of CHD Incidence in Middle-Aged and Older Chinese: the Dongfeng-Tongji Cohort Study.
abstract: OBJECTIVE
  To analyze the independent and combined relations of sleep duration and midday napping with coronary heart diseases (CHD) incidence along with the underlying changes of cardiovascular disease (CVD) risk factors among Chinese adults.
  
  
  METHODS
  We included 19,370 individuals aged 62.8 years at baseline from September 2008 to June 2010, and they were followed until October 2013. Cox proportional hazards models and general linear models were used for multivariate longitudinal analyses.
  
  
  RESULTS
  Compared with sleeping 7- < 8 h/night, the hazard ratio (HR) of CHD incidence was 1.33 (95% CI = 1.10 to 1.62) for sleeping ≥ 10 h/night. The association was particularly evident among individuals who were normal weight and without diabetes. Similarly, the HR of incident CHD was 1.25 (95% CI = 1.05 to 1.49) for midday napping > 90 min compared with 1-30 min. When sleep duration and midday napping were combined, individuals having sleep duration ≥ 10 h and midday napping > 90 min were at a greater risk of CHD than those with sleeping 7- < 8 h and napping 1-30 min: the HR was 1.67 (95% CI = 1.04 to 2.66; P for trend = 0.017). In addition, longer sleep duration ≥ 10 h was significantly associated with increases in triglycerides and waist circumference, and a reduction in HDL-cholesterol; while longer midday napping > 90 min was related to increased waist circumference.
  
  
  CONCLUSIONS
  Both longer sleep duration and midday napping were independently and jointly associated with a higher risk of CHD incidence, and altered lipid profile and waist circumference may partially explain the relationships.
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Liangle
authors.initials: L
authors.lastname: Yang
authors.affiliation: Dongfeng Central Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.
authors.forename: Handong
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Meian
authors.initials: M
authors.lastname: He
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: An
authors.initials: A
authors.lastname: Pan
authors.affiliation: Dongfeng Central Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.
authors.forename: Xiulou
authors.initials: X
authors.lastname: Li
authors.affiliation: Dongfeng Central Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.
authors.forename: Xinwen
authors.initials: X
authors.lastname: Min
authors.affiliation: Dongfeng Central Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.
authors.forename: Ce
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Dongfeng Central Hospital, Dongfeng Motor Corporation and Hubei University of Medicine, Shiyan, China.|Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Chengwei
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wei
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Miao
authors.affiliation: Department of Nutrition and Department of Epidemiology, Harvard School of Public Health, Boston, MA.
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Tangchun
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Occupational and Environmental Health and Ministry of Education Key Lab for Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data*; D002681:China / Q000208:ethnology; D008076:Cholesterol, HDL / Q000097:blood; D015331:Cohort Studies; D003327:Coronary Disease / Q000097:blood / Q000209:etiology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D055105:Waist Circumference
chemical_list: D008076:Cholesterol, HDL; D014280:Triglycerides
keywords: follow-up; incident CHD; midday napping; prospective studies; sleep duration