Shift work disorder in a random population sample : prevalence and comorbidities

Few studies have investigated the presence of shift work disorder (SWD) in the general community. We addressed many of the limitations in this literature and present new findings. SWD has been treated as an ‘all or none’ construct but we propose the need to consider the ‘severity’ of the disorder. Using random digit dialling, we randomly recruited 1163 participants. Participants completed an extensive battery of scales and questions concerning work, health and individual differences. Three questions based on the criteria from the International Classification for Sleep Disorders were used to categorise participants with SWD (n = 176). In addition, we asked participants whether SWD interfered with aspects of their life and high ratings were used to define severe shift work disorder (SSWD). The prevalence of SWD was 32.1% among night workers and 10.1% in day workers (p,.001). SSWD was present in 9.1% of night workers and 1.3% of day workers (p,.001). Adjusted logistic regression analyses found significant associations between SWD and night work (OR = 3.35, CI 2.19-5.12), weekly work hours (OR = 1.02, CI 1.00–1.04), short sleep (#6 h; OR = 2.93, CI 1.94–4.41), languidity (OR = 1.11, CI 1.06–1.16) and resilience (OR = 0.56, CI 0.43–0.81). Night work, short sleep, languidity, and hypertension were significantly associated with SSWD. Overall, participants with SSWD slept 0.80 h less than other participants (p,.001). Night work, short sleep and languidity were associated with both SWD and SSWD. Day workers with SWD symptoms reported significantly shorter sleep duration, higher levels of languidity and worked longer working hours compared to day workers without SWD

Predictors of shift work disorder among nurses : a longitudinal study

Background: Shift work is associated with sleep problems and impaired health. The main aim of the present study was to explore predictors of developing shift work disorder (SWD) among Norwegian nurses using a longitudinal design. Methods: A total of 1533 nurses participating in a survey on shift work, sleep and health responded to questionnaires at baseline and at follow-up about two years later. SWD was defined as problems of excessive sleepiness and/or complaints of insomnia related to the work schedule. Results and Conclusions: There was a significant reduction (p < 0.001) in the prevalence of SWD from baseline to follow-up, from 35.7% to 28.6%. Logistic regression analyses showed significant risks of having SWD at follow-up and the following variables measured at baseline: number of nights worked the last year (OR = 1.01, 95% CI = 1.01–1.02), having SWD (OR = 5.19, 95% CI = 3.74–7.20), composite score on the Epworth Sleepiness Scale (OR = 1.08, 95% CI = 1.04–1.13), use of melatonin (OR = 4.20, 95% CI = 1.33–13.33), use of bright light therapy (OR = 3.10, 95% CI 1.14–8.39), and symptoms of depression measured by the Hospital Anxiety and Depression Scale (OR = 1.07, 95% CI = 1.00–1.14). In addition, leaving night work between baseline and follow-up was associated with a significantly reduced risk of SWD atfollow-up (OR = 0.12, 95% CI = 0.07–0.22)