title: A Novel, Open Access Method to Assess Sleep Duration Using a Wrist-Worn Accelerometer.
abstract: Wrist-worn accelerometers are increasingly being used for the assessment of physical activity in population studies, but little is known about their value for sleep assessment. We developed a novel method of assessing sleep duration using data from 4,094 Whitehall II Study (United Kingdom, 2012-2013) participants aged 60-83 who wore the accelerometer for 9 consecutive days, filled in a sleep log and reported sleep duration via questionnaire. Our sleep detection algorithm defined (nocturnal) sleep as a period of sustained inactivity, itself detected as the absence of change in arm angle greater than 5 degrees for 5 minutes or more, during a period recorded as sleep by the participant in their sleep log. The resulting estimate of sleep duration had a moderate (but similar to previous findings) agreement with questionnaire based measures for time in bed, defined as the difference between sleep onset and waking time (kappa = 0.32, 95%CI:0.29,0.34) and total sleep duration (kappa = 0.39, 0.36,0.42). This estimate was lower for time in bed for women, depressed participants, those reporting more insomnia symptoms, and on weekend days. No such group differences were found for total sleep duration. Our algorithm was validated against data from a polysomnography study on 28 persons which found a longer time window and lower angle threshold to have better sensitivity to wakefulness, while the reverse was true for sensitivity to sleep. The novelty of our method is the use of a generic algorithm that will allow comparison between studies rather than a "count" based, device specific method.
authors.affiliation: MoveLab - Physical activity and exercise research, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.|Netherlands eScience Center, Amsterdam, The Netherlands.
authors.forename: Vincent T
authors.initials: VT
authors.lastname: van Hees
authors.affiliation: Department of Epidemiology & Public Health, University College London, London, United Kingdom.
authors.forename: Séverine
authors.initials: S
authors.lastname: Sabia
authors.affiliation: Regional Sleep Service, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
authors.forename: Kirstie N
authors.initials: KN
authors.lastname: Anderson
authors.affiliation: MoveLab - Physical activity and exercise research, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Denton
authors.affiliation: Regional Sleep Service, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Oliver
authors.affiliation: MoveLab - Physical activity and exercise research, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Catt
authors.affiliation: Department of Epidemiology & Public Health, University College London, London, United Kingdom.
authors.forename: Jessica G
authors.initials: JG
authors.lastname: Abell
authors.affiliation: Department of Epidemiology & Public Health, University College London, London, United Kingdom.
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimäki
authors.affiliation: MoveLab - Physical activity and exercise research, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Trenell
authors.affiliation: Department of Epidemiology & Public Health, University College London, London, United Kingdom.|Centre for Research in Epidemiology and Population Health, INSERM, Unit 1018, Villejuif, France.
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
mesh_terms: D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation* / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003863:Depression / Q000150:complications; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D009043:Motor Activity; D017286:Polysomnography / Q000295:instrumentation* / Q000379:methods; D012737:Sex Factors; D012890:Sleep; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis; D012893:Sleep Wake Disorders / Q000175:diagnosis; D011795:Surveys and Questionnaires; D013997:Time Factors; D006113:United Kingdom; D014953:Wrist