Insomnia and long sleep duration are risk factors for later work disability. The Hordaland Health Study

Authors

  • BØRGE SIVERTSEN,

    1. Department of Clinical Psychology, University of Bergen, Bergen, Norway
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  • SIMON ØVERLAND,

    1. Faculty of Psychology, Research Centre for Health Promotion, University of Bergen, Bergen
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  • STÅLE PALLESEN,

    1. Department of Psychosocial Science, University of Bergen, Bergen
    2. Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen
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  • BJØRN BJORVATN,

    1. Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen
    2. Department of Public Health and Primary Health Care, University of Bergen, Bergen
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  • INGER HILDE NORDHUS,

    1. Department of Clinical Psychology, University of Bergen, Bergen, Norway
    2. Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen
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  • JOHN GUNNAR MÆLAND,

    1. Department of Public Health and Primary Health Care, University of Bergen, Bergen
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  • ARNSTEIN MYKLETUN

    1. Faculty of Psychology, Research Centre for Health Promotion, University of Bergen, Bergen
    2. Department of Mental Health, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
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Børge Sivertsen, PhD, Department of Clinical Psychology, University of Bergen, Christiesgt. 12, 5015 Bergen, Norway. Tel.: +47 55 58 88 76; fax: +47 55 58 98 77; e-mail: borge.sivertsen@psykp.uib.no

Summary

Both insomnia and sleep duration have previously been linked with a range of adverse outcomes, but no studies have explored their relative effect on subsequent work disability. The aim of the present study was to investigate the contribution of insomnia versus sleep duration to later long-term work disability. Using a historical cohort design with 4-year follow-up, data on insomnia, sleep duration and potential confounders were gathered from 6599 working persons (40–45 years). The outcome was award of disability pension, as registered in the National Insurance Administration. After controlling for baseline exposure to disability and sick leave, insomnia was a strong predictor of permanent work disability [odds ratio (OR) = 4.56], and this effect remained significant after controlling for sleep duration, as well as for other possible confounders (OR = 1.88). Short sleep duration was not significantly associated with subsequent work disability, while long sleep duration (>8.5 h) did predict work disability (OR = 2.96), also in the fully adjusted model (OR = 2.14).The present study demonstrates that both insomnia and long sleep duration are strong and independent risk factors for subsequent work disability.

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