title: Sleep duration and sleep quality in relation to 12-year cardiovascular disease incidence: the MORGEN study.
abstract: OBJECTIVE
  We studied sleep duration and sleep quality in relation to cardiovascular disease (CVD) incidence.
  
  
  METHODS
  Dutch population-based cohort study.
  
  
  METHODS
  20,432 men and women aged 20-65 and with no history of CVD.
  
  
  METHODS
  N/A.
  
  
  METHODS
  Sleep duration and sleep quality were assessed by a self-administered questionnaire. Morbidity data, vital status, and causes of death were obtained through linkage with several national registries. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using Cox proportional hazards models.
  
  
  RESULTS
  During 10-15 years of follow-up, 1,486 CVD and 1,148 coronary heart disease (CHD) events occurred. Short sleepers (≤ 6 h) had a 15% higher risk of total CVD (HR: 1.15; 95%CI: 1.00-1.32) and a 23% higher risk of CHD (HR: 1.23 [1.04-1.45]) compared to normal sleepers (7 h) after adjustment for all confounders. Additional adjustment for intermediate biological risk factors attenuated these relative risks to 1.11 (0.97-1.27) for total CVD and to 1.19 (1.00-1.40) for CHD. Short sleepers with poor sleep quality had a 63% higher risk of CVD (HR: 1.63 [1.21-2.19]) and a 79% higher risk of CHD incidence (HR: 1.79 [1.24-2.58]) compared to normal sleepers with good sleep quality, after adjustments for all confounders. We observed no associations between long sleep duration (≥ 9 h) and CVD or CHD incidence.
  
  
  CONCLUSIONS
  Short sleepers, especially those with poor sleep quality, have an increased risk of total CVD and CHD incidence. Future investigations should not only focus on sleep duration, but should also take sleep quality into account.
authors: Centre for Prevention and Health Services Research, National Institute for Public Health and the Environment, Bilthoven, The Netherlands. marieke.hoevenaar@rivm.nl
authors: Marieke P
authors: MP
authors: Hoevenaar-Blom
authors: Annemieke M W
authors: AM
authors: Spijkerman
authors: Daan
authors: D
authors: Kromhout
authors: Julia F
authors: JF
authors: van den Berg
authors: W M Monique
authors: WM
authors: Verschuren
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D016016:Proportional Hazards Models; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000150:complications / Q000453:epidemiology; D011795:Surveys and Questionnaires; D055815:Young Adult