Does insomnia predict sick leave? The Hordaland Health Study

Objective: The purpose of this study is to prospectively examine the independent contribution of symptoms of insomnia oil sick leave. Methods: We used a historical cohort design with 4 years of follow-up. Information oil sick leave was obtained from Norwegian official registry data and merged with health information from the Hordaland Health Study in Western Not-way, 1997 to 1999. Six thousand eight hundred ninety-two participants aged 40 to 45 years were assessed for self-reported symptoms of insomnia, sociodemographic factors, lifestyle behaviors, body mass index, symptoms of sleep apnea, anxiety depression, as well as a range of somatic diagnoses, somatic symptoms, and pain. The Outcome was the total number of sick days during a 4-year follow-up period, as registered in the official registries by the National Insurance Administration. Results: Overall, insomnia was found to be a significant predictor of sick leave [odds ratio (OR)=2.20; 95% confidence interval (CI), 1.77-2.74], and the effect remained significant when adjusting for possible confounders (OR=1.51; 95% CI 1.19-1.94). The effect increased with longer durations of sickness leave. Conclusion: This is the first study to demonstrate that insomnia is an independent risk factor for long-term sick leave. (c) 2009 Elsevier Inc. All rights reserved.