title: Relationships between sleep duration and von Willebrand factor, factor VII, and fibrinogen: Whitehall II study.
abstract: OBJECTIVE
  To examine the relationship between sleep duration and hemostatic factors in a well-characterized cohort.
  
  
  RESULTS
  The relationship between self-reported sleep duration and von Willebrand factor (vWF), fibrinogen, and factor VII was examined in approximately 6400 individuals from the Whitehall II Study. The analysis was stratified by sex (interaction P<0.001). After multiple adjustments, vWF levels were significantly higher in men with both short sleep duration (≤6 hours per night; 1.05 [95% CI, 1.01 to 1.08] [data given as geometric mean]) and long sleep duration (≥8 hours per night; 1.05 [95% CI, 1.02 to 1.08]) compared with those who slept 7 hours (P<0.05 for both). In women, levels of vWF were significantly higher in individuals who slept 8 hours or longer (1.11 [95% CI, 1.06 to 1.16]) compared with 7 hours (P<0.05). This difference was observed in premenopausal and postmenopausal women. In women, the association was nonlinear (P=0.02), but not in men (P=0.09). No statistically significant associations between sleep duration and fibrinogen or factor VII were observed.
  
  
  CONCLUSIONS
  Men who slept for short and long durations had higher vWF levels. In women, there was a significant nonlinear association. The highest levels were observed in long sleepers, irrespective of menopausal status. No major associations between sleep and factor VII or fibrinogen were observed. Longitudinal studies are required to investigate causality.
authors.affiliation: University of Warwick, Clinical Sciences Research Institute, Warwick Medical School, UHCW Campus, Clifford Bridge Road, Coventry CV2 2DX, England. michelle.miller@warwick.ac.uk
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Miller
authors.forename: Ngianga-Bakwin
authors.initials: NB
authors.lastname: Kandala
authors.forename: Meena
authors.initials: M
authors.lastname: Kumari
authors.forename: Michael G
authors.initials: MG
authors.lastname: Marmot
authors.forename: Francesco P
authors.initials: FP
authors.lastname: Cappuccio
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005167:Factor VII / Q000378:metabolism*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology; D017697:Premenopause / Q000502:physiology; D012044:Regression Analysis; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D014841:von Willebrand Factor; D005167:Factor VII; D005340:Fibrinogen