Siri Waage

University of Bergen | UiB · Department of Public Health and Primary Health Care

Sleep loss due to short time off between shifts has been proposed as a mechanism contributing to impaired functioning in occupational settings. This laboratory crossover trial (ClinicalTrials.gov identifier: NCT05162105, N = 66) compared subjective sleepiness, mood, and cognitive performance on a day shift after an evening shift with only 8 h off b...

Background Global nursing shortages necessitate the identification of mitigatable factors that may reduce nursing absence and turnover. Fatigue has been shown to be associated with these issues. This study aimed to identify factors leading to development of or recovery from excessive fatigue in nurses as these can offer actionable avenues for prote...

This trial presents a laboratory model investigating the effect of quick returns (QRs, <11 h time off between shifts) on sleep and pre-sleep arousal. Using a crossover design, 63 participants worked a simulated QR condition (8 h time off between consecutive evening- and day shifts) and a day-day (DD) condition (16 h time off between consecutive day...

Study objectives: To investigate the effect of a work schedule with abated quick returns (i.e., >11 hours between two shifts) on insomnia, daytime sleepiness, and work-related fatigue compared to a shift schedule maintaining the usual number of quick returns. Methods: A two-armed cluster randomized controlled trial including 66 units was conduct...

Disturbed sleep and circadian disruption are reported to increase the risk of infections. People with an evening circadian preference and night workers typically report insufficient sleep, and the aims of the present study were to investigate possible associations between various types of infections and circadian preference and shift work status. D...

Background The preset study aimed to explore whether work schedules and sleep disorders predict the onset of headache. Methods A longitudinal study was conducted with questionnaire data from 2014 (baseline) and 2017 (follow-up) on work schedule, number of night shifts, number of quick returns, insomnia, shift work disorder (SWD), restless legs syn...

Objectives The aims were to explore multidimensional sleep health and the different dimensions of sleep health in the adult Norwegian population in relation to sex, age, education, circadian preference, and chronic insomnia. Methods A representative sample of 1028 Norwegians, aged 18 + years completed a cross-sectional web-based survey. Sleep heal...

Objective: The objective was to assess the association between self-reported infections and sleep duration, sleep debt, chronic insomnia, and insomnia severity. Methods: In total, 1023 participants were recruited from the Norwegian practice-based research network in general practice to a cross-sectional online survey with validated questions abo...

Aim To investigate whether pain, sleep duration, insomnia, sleepiness, work-related factors, anxiety, and depression associate with excessive fatigue in nurses. Background Fatigue among nurses is a problem in the context of ongoing nursing shortages. While myriad factors are associated with fatigue not all relationships are understood. Prior studi...

The present study estimated the frequency of using methods or tricks to fall asleep in the general Norwegian population. Further, people with chronic insomnia were compared with people without chronic insomnia. A representative sample of 1028 participants aged 18 years or older completed a web-based survey. The response rate was 33.5%. Insomnia sym...

Background: This study aimed to investigate whether different types of changes in the work schedule of nurses working rotating shifts during the COVID-19 pandemic were associated with sleep duration, sleep quality, and turnover intention. Methods: Cross-sectional questionnaire data from 694 nurses participating in the SUrvey of Shift work, Sleep...

Background Shift work, i.e., non-standard work hours, has been associated with both short- and long-term sickness absence. However, findings are inconsistent and inconclusive. Thus far, no comprehensive meta-analytic synthesis on the relationship between shift work and sickness absence has been published. The aims of the planned systematic review a...

Objectives: To explore whether a change in work schedule was associated with a change in the probability of prescribed sleep medication use. Methods: A longitudinal study with annual questionnaire data (2008/2009-2021, except 2019) on work schedule (day work only, shift work without nights and shift work with nights) and prescribed sleep medicat...

Background Shift work disorder (SWD) is highly prevalent among shift-working nurses and has multiple negative health-related effects. There is a dearth of insight into career-related decisions made by nurses suffering from SWD, for instance in terms of their intention to quit work (turnover intention). In this study, we aimed to investigate the ass...

The study examined sleep and sleepiness among shift working Helicopter Emergency Medical Service pilots from Norway (Norwegian Air Ambulance; NAA) and Austria (Christophorus Flugrettungverein; CFV). Both pilot groups (N = 47) worked seven consecutive 24 h shifts. Sleep was assessed by diaries and actigraphy while sleepiness was assessed by the Karo...

Introduction In shift work, quick returns refer to transitions between two shifts with less than 11 hours available rest time. Twenty-three per cent of employees in European countries reported having quick returns. Quick returns are related to short sleep duration, fatigue, sleepiness, work-related accidents and sickness absence. The present study...

Night work leads to sleepiness and reduced vigilant attention during work hours, and bright light interventions may reduce such effects. It is also known that total sleep deprivation impairs cognitive flexibility as measured by reversal learning tasks. Whether night work impairs reversal learning task performance or if bright light can mitigate rev...

Background: The prevalence of restless legs syndrome (RLS) among adults in the general population is around 5-10 %. Few studies have been conducted on the prevalence among patients who consult their general practitioner. There are also few studies on associations between RLS and other common complaints such as irritable bowel syndrome (IBS), chron...

Aim To estimate the prevalence of sleep medication and melatonin use among nurses and to assess if factors related to work, sleep or mental health, were associated with such use. Design A cross-sectional study. Methods A questionnaire survey including 2,798 Norwegian nurses. Associations were estimated using a modified Poisson regression model....

The traits languidity (tendency to become tired/sleepy upon losing sleep) and flexibility (ability to sleep and work at odd times) have been implicated in shift work tolerance. However, there is a dearth of knowledge about their temporal stability. The aim of the present study was to explore these traits during a long follow-up (FU) period and iden...

Background Nurses are in the frontline and play an important role in the battle against the COrona VIrus Disease-2019 (COVID-19) pandemic. Sleep problems among health care workers are likely to increase due to the pandemic. However, it is conceivable that negative health outcomes related to the pandemic fluctuate with the infection rate waves of th...

Daylight Saving Time is highly debated and associated with several health risks. Health experts recommend terminating adjusting the clock time, and to keep permanent standard (winter) time year around. The aims of the study were to investigate preferences for keeping or terminating this biannual adjustment of clock times and for permanent standard...

Objectives: No systematic review or meta-analysis concerning the prevalence of shift work disorder (SWD) has been conducted so far. The aim was thus to review prevalence studies of SWD, to calculate an overall prevalence by a random effects meta-analysis approach and investigate correlates of SWD prevalence using a random-effects meta-regression. M...

This study aimed to explore how changes in the work schedule would affect the prevalence of Shift Work Disorder (SWD) over time. Two-year follow-up data from 1076 nurses participating in the longitudinal SUrvey of Shift work, Sleep and Health among Norwegian nurses (SUSSH) were included in the study. The questionnaires included measures of work-rel...

The aim of this study was to investigate the association between self-reported seasonality, i.e., seasonal variations in mood and related behavior, and chronotype, and between self-reported seasonality and home address’ latitude. Data were collected from an online questionnaire with 45,338 participants. Seasonality and chronotype were measured with...

Light can be used to facilitate alertness, task performance and circadian adaptation during night work. Novel strategies for illumination of workplaces, using ceiling mounted LED-luminaires, allow the use of a range of different light conditions, altering intensity and spectral composition. This study (ClinicalTrials.gov Identifier NCT03203538) inv...

This report summarizes the main findings and recommendations of a large Nordic project 'Working hours, health, well-being and participation in working life' (WOW, 2015-2021). The project has produced over 100 original publications on the societal and socio-economic differences and trends of Nordic working hours, and on the associations, countermeas...

Objectives The objective was to investigate effects of timed bright light treatment on subjective and objective measures of sleepiness during three consecutive night shifts among hospital nurses. Methods Thirty-five nurses were exposed to bright light (10,000 lux) and red dim light (100 lux) during three consecutive night shifts in a counter-balan...

Purpose To investigate the relationship between self-reported everyday memory problems the last month, and: (a) shift work schedule, (b) night shifts and quick returns worked the last year, and (c) sleep duration the last month. Methods In all, 1,275 nurses completed the Everyday Memory Questionnaire – revised, and answered questions about shift w...

Objectives: Shift work is associated with several negative health effects. The underlying pathophysiological mechanisms are unclear, but low-grade inflammation has been suggested to play a role. This project aimed to determine whether levels of immunological biomarkers differ depending on work schedule, self-reported sleep duration, self-reported s...

The present study aimed to investigate the effects of shift work on sleep among pilots and Helicopter Emergency Medical Service crew members (HCM) in the Norwegian Air Ambulance. Sleep was assessed by diaries and actigraphy during a workweek (24 h duty for 7 consecutive days) in the winter season and a workweek during the summer season in pilots an...

Use of blue-enriched light has received increasing interest regarding its activating and performance sustaining effects. However, studies assessing effects of such light during night work are few, and novel strategies for lighting using light emitting diode (LED) technology need to be researched. In a counterbalanced crossover design, we investigat...

Objective This study aimed to investigate how change in the number of quick returns [(QR) <11 hours between consecutive shifts] longitudinally is associated with risk of occupational accidents among nurses. Methods Two-year follow-up data from 1692 nurses participating in the Survey of Shiftwork, Sleep and Health among Norwegian nurses (SUSSH) (me...

Personality has been hypothesized to act as antecedent as well as an outcome of workplace bullying. Still, investigations on the longitudinal relationship between bullying and personality are scarce. We investigated the relationship between accumulated exposure to bullying at work and subsequent changes in psychological hardiness. Additionally, we...

Purpose To determine whether common work schedule characteristics among Norwegian nurses were associated with subjective pain complaints. Methods A cross-sectional study in a sample of 1585 nurses, part of the longitudinal questionnaire-based cohort project ‘Survey of Shift work, Sleep and Health’ (SUSSH). Pain from six regions were assessed: ‘hea...

Objectives To investigate how a standard ceiling mounted light-emitting diode (LED)-based bright light intervention affected alertness and neurobehavioural performance during three consecutive simulated night shifts, and timing of circadian rhythm after the shifts. Methods Twenty seven participants (20 females, 21.4±2.1 years; mean±SD) worked thre...

There is a paucity of studies investigating how sexual activity is perceived to influence sleep, despite conceptions about significant gender differences regarding this issue. In all, 4000 persons, aged between 18 and 55 years, were randomly drawn from the Norwegian Population Registry and invited to participate in a postal survey. The respondents...

Purpose To examine the effects of shift work and extended working hours on sleepiness among pilots and Helicopter Emergency Medical Service (HEMS) crew members in the Norwegian Air Ambulance. Methods This field study investigated sleepiness during 3 consecutive weeks: the week before work, the work week, and the week after work. The pilots and HEM...

Objectives: To evaluate different work schedules, short rest time between shifts (quick returns), and night shift exposure for their possible adverse effects on different lifestyle factors in a 6-year follow-up study. Methods: Data stemmed from “The Survey of Shiftwork, Sleep and Health,” a cohort study of Norwegian nurses started in 2008/9. The da...

Purpose The aim of this study was to examine whether less than 11 h between shifts (i.e., quick returns, QRs) and night shifts is associated with self-reported work-related accidents, near accidents or dozing off at work in a sample of nurses. Methods The study was based on cross-sectional data from 1784 nurses (response rate = 60%; mean age = 40....

Purpose The aim of this study was to investigate the effects of long working hours (≥ 12 h shifts) on sick leave using objective records of shift work exposure and of sick leave. Methods A total of 1538 nurses (mean age 42.5, SD 12.0; response rate 42%) participated. Payroll and archival sick leave data over a 4-year period were retrieved from emp...

Background: This study investigates insomnia as a partial mediator in the relationship between personality and symptoms of anxiety and depression. Methods: The study is based on partly longitudinal data from the ongoing cohort study “Survey of Shift work, Sleep, and Health” (SUSSH) among Norwegian nurses, a survey examining the work situation and h...

Objective: We compared subjectively reported sleepiness and fatigue as well as causes and management strategies for combating sleepiness among pilots working in 2 different helicopter emergency medical services operating with different shift systems. Methods: Pilots from the Norwegian Air Ambulance (NAA) and Christophorus Flugrettungsverein (CFV...

Objectives To investigate associations between different types of headaches and shift work. Design, participants and outcome measures Nurses with different work schedules (day work, two-shift rotation, night work, three-shift rotation) participated in a cohort study with annual surveys that started in 2008/2009. In 2014 (wave 6), a comprehensive h...

The present study comprised 1,781 nurses who participated in an investigation about working conditions, sleep, and health. They answered a questionnaire about age, sex, marital status, children living at home, work hours per week, number of night shifts last year, and total sleep duration and that also included a validated instrument assessing work...

Introduction Results from previous studies are ambiguous regarding the relationship between long working hours and sick leave, and there are obvious methodological shortcomings in many of the previous conducted studies. The aim of this study was to investigate the effects of long working hours (≥12 hour shifts) on later sick leave using objective r...

PurposeWe investigated which job demands and job resources were predictive of mental health-related long-term sickness absence (LTSA) in nurses. Methods The data of 2059 nurses were obtained from the Norwegian survey of Shift work, Sleep and Health. Job demands (psychological demands, role conflict, and harassment at the workplace) and job resource...

Objectives: Major age and sex differences are reported in bedroom habits and bedroom characteristics. However, few studies have investigated whether such bedroom habits and characteristics differ between patients with chronic insomnia disorder and good sleepers. Methods: We assessed the association between several bedroom habits (i.e. electronic...

Insomnia and excessive sleepiness are among the most commonly reported sleep problems related to shift work. Sleep-related movement disorders have, however, received far less attention in relation to such work schedules. The objective of this study was to investigate the association between different shift work schedules and the prevalence of Restl...

Objectives The aim of this study was to investigate changes in body mass index (BMI) between different work schedules and different average number of yearly night shifts over a four-year follow-up period. Methods A prospective study of Norwegian nurses (N=2965) with different work schedules was conducted: day only, two-shift rotation (day and eveni...

Objective: We aimed to compared sleep characteristics associated with quick returns (QRs, <11 hours between shift intervals) with those associated with other common shift transitions. Methods: Sixty-seven nurses completed a 2-week work and sleep diary (94.0% female, mean age 47.7 years). A multilevel fixed effects model was used to examine the s...

Commentary on: Lamont S, Brunero S, Perry L, et al. ‘Mental health day’ sickness absence amongst nurses and midwives: workplace, workforce, psychosocial and health characteristics. J Adv Nurs 2016 doi: 10.1111/jan.13212. [Epub ahead of print 16 Nov 2016]. Sickness absence is a major problem for society, and is higher among health professionals com...

Objective: The objective of this study was to estimate the prevalence of different bedroom habits/preferences, and to assess whether these habits/preferences differ with age and sex. Methods: A population-based Norwegian cross-sectional telephone survey with 1001 of 1599 randomly selected adults (63% response rate) was performed. The questions a...

Objectives The purpose of this study was to use objective registry data to prospectively investigate the effects of quick returns (QR, <11 hours of rest between shifts) and night shifts on sick leave. Methods A total of 1538 nurses (response rate =41.5%) answered questionnaires on demographics and personality and provided consent to link this info...

Numerous cross-sectional studies report high prevalence rates of sleepiness and insomnia in shift workers, but few longitudinal studies exist. We investigated trajectories of sleepiness and insomnia symptoms in a sample of Norwegian nurses across four measurements, spanning a total of four years (sleepiness) and five years (insomnia). The participa...

The aim of this study was to investigate whether different shift work schedules were associated with nonrapid eye movement (NREM)-and/or REM-related parasomnias. A total of 2198 nurses with different work schedules participated in a longitudinal cohort study. The parasomnia questions were included in the fourth wave of the data collection, with a r...

The aim of this study was to investigate whether different shift work schedules were associated with nonrapid eye movement (NREM)- and/or REM-related parasomnias. A total of 2198 nurses with different work schedules participated in a longitudinal cohort study. The parasomnia questions were included in the fourth wave of the data collection, with a...

The 2014 workshop on "Co-ordination of research on working hours and health in the Nordic countries" was held at the Finnish Institute of Occupational Health on the 23rd-24th October 2014. The overall purpose of the workshop was to provide a platform for cooperation and development of high-quality research projects on working hours and health in th...

Unlabelled: A systematic literature search was carried out to investigate the relationship between quick returns (i.e., 11.0 hours or less between two consecutive shifts) and outcome measures of health, sleep, functional ability and work-life balance. A total of 22 studies published in 21 articles were included. Three types of quick returns were d...

Objectives: We investigated whether the number of work shifts separated by less than 11 hours (quick returns) at baseline (T1) could predict health problems in nurses at 1-year follow-up (T2). Methods: 1224 nurses responded to a questionnaire-based survey in 2009 (T1) and 2010 (T2). Crude and adjusted logistic regression analyses were completed...

Background: An association between spontaneous abortions and shift work has been suggested, but present research results are conflicting. The aim of the study is to evaluate the relationship between spontaneous abortions among nurses, shift schedules, and nights worked.

Objectives Our aim was to study the relationship between spontaneous abortions among nurses working three different types of shift schedules; permanent day shift, three shift rotation, and permanent night shift. Methods From a cohort of nurses in Norway established in 2008, we identified 1083 female workers who worked the same type of shift schedul...

Shift and night work are associated with several negative outcomes. The aim of this study was to make a systematic review of all studies which examine effects of shift and night work in the offshore petroleum industry, to synthesize the knowledge of how shift work offshore may affect the workers. Searches for studies concerning effects on health, s...

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...

This study compared subjective sleep and subjective health complaints among Norwegian oil rig workers, before and after a two week work period. The study also compared differences between two different work schedules. The workers worked either two weeks of day shift (n=90) or two weeks of a swing shift schedule (n=93), involving one week of night s...

Shift work, and especially night work, is associated with poor health. Nurses, work a variety of work schedules including night work. So far, few studies have specifically investigated sleep and health among intensive care nurses. We investigated sleep, sleepiness, fatigue, subjective health complaints, anxiety and depression in 150 intensive care...

Examine sleepiness in three different shift work schedules (within-subject design) in the offshore oil industry. Sleepiness was measured in 19 oil rig workers, using subjective (Karolinska Sleepiness Scale; Accumulated Time with Sleepiness) and objective measures (reaction time). The work schedule consisted of two weeks of 12 h day work (day shifts...

The aim was to investigate how working in an extreme and isolated environment in the Arctic affected the diurnal rhythm of saliva cortisol. Field study. Twenty-five male tunnel workers were screened during 3 different working cycles with different light conditions during a 9-month construction period; April/May (24 hours [h] light), September/Octob...

In this study we examine sleep during adaptation and readaptation to different shift work schedules in the offshore oil industry. The sleep of 19 offshore workers was assessed daily for 1 week before, during the work period, and for 1 week after 3 different work schedules: (1) day (14 consecutive days of work), (2) night (14 consecutive nights of w...