Prevalence of insomnia in shift workers: a systematic review

Impact of associated factors and adherence to Mediterranean diet on insomnia among Arab men living in Jordan

The detrimental health and economic burdens associated with insomnia have led to investigations examining its prevalence and potential predictors to utilize this information in insomnia prevention/treatment. Ethnicity, gender, and lifestyle habits are among the important predictors associated with insomnia. The aim of this study was to examine the prevalence of insomnia and potential predictors of insomnia among Arab men living in Jordan, including Mediterranean diet (MD) adherence. The inclusion criteria of this cross-sectional, correlational study were: (1) being a male; (2) aged 18 and older; and (3) able to read, write, and speak the Arabic language. Online questionnaires were used to assess participants' sociodemographic information, adherence to the MD, physical activity, and insomnia. Results demonstrated that there was a high prevalence of insomnia (53.9%) among the study's participants (N = 529). Moreover, in the unadjusted model, the study revealed that being unemployed (OR = 1.90, p = 0.018), categorized as dehydrated (OR = 1.20, p = 0.020), overweight (OR = 1.30, p = 0.035), sleeping less than 6 hours/day (OR = 2.10, p < 0.001), and having high adherence to the MD (OR = 1.60, p = 0.010) were predictors of insomnia. Meanwhile, the adjusted multivariate logistic regression model indicated that being married (OR = 1.20, p = 0.020) played a significant protective role against developing insomnia among Arab men. While high adherence to MD (OR = 1.642, p = 0.028) and sleeping less than 6 hours/day (OR = 2.760, p < 0.001) were relative risk factors for experiencing insomnia. The high prevalence of insomnia in this population and the identification of possible predictors associated with insomnia, and the unexpected relationship between adherence to the MD and insomnia warrant further in-depth investigations that may help promote the understanding of the factors associated with insomnia and facilitate the development of interventions to target it.

A Multiple Mediator Model of Depression, Dysfunctional Beliefs about Sleep, and Sleep Effort in the Relationship between Psychological Inflexibility and Insomnia in Shift Working Nurses

The aims of this study were to explore the influence of shift working nursing professionals' psychological inflexibility on their level of insomnia. Additionally, we investigated the mediation effect of depression and sleep-related cognitions on this association. An online survey was conducted among 202 nursing professionals at Asan Medical Center from July to August, 2023. Participants responded to questionnaires including the Insomnia Severity Index (ISI), Acceptance and Action Questionnaire-II (AAQ-II), Dysfunctional Beliefs and Attitudes about Sleep - 16 (DBAS-16), Glasgow Sleep Effort Scale (GSES), Patient Health Questionnaire-9 items (PHQ-9), and the Discrepancy between desired time in bed and desired total sleep time index (DBST index). Pearson's correlation and linear regression were performed to explore the factors predicting ISI scores. Mediation analysis was implemented. Linear regression revealed that insomnia severity was predicted by DBAS-16 (β = 0.15, p = 0.008), GSES (β = 0.48, p < 0.001), and PHQ-9 (β = 0.26, p < 0.001). Mediation analysis showed that the relationship between the psychological inflexibility of shift-working nursing professionals' and insomnia severity was fully mediated by depression, dysfunctional beliefs about sleep, and sleep effort. Psychological inflexibility does not directly influence insomnia severity, but depression, dysfunctional beliefs about sleep, and sleep effort fully mediate the relationship.

Association Between Dietary Fiber Intake and Sleep Disorders: Based on the NHANES Database

OBJECTIVE

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) database, the primary objective of this investigation was to examine the relationship between dietary fiber intake (DFI) and sleep disorders.

METHODS

For analysis, data from three consecutive cycles of NHANES (2009-2014) were pooled. The independent variable of interest was DFI, while the dependent variable was sleep disorders. Weighted logistic regression was employed to model the relationship between the two variables. Subgroup analyses were conducted, stratified, and adjusted to explore the association between DFI and sleep disorders.

RESULTS

This study encompassed a cohort of 14,360 samples. Logistic regression results revealed a significant inverse association between higher DFI and the risk of sleep disorders (OR: 0.99, 95% CI: 0.98-1.00, p = 0.005). Stratified analysis demonstrated significant interactive effects of gender and physical activity on the association between DFI and sleep disorders (interaction p = 0.017, p = 0.061). Quartile-stratified analysis of DFI showed that in the crude model, Q4 exhibited a significant protective impact against sleep disorders (OR: 0.76, 95% CI: 0.59-0.97, p = 0.026). In model I, which adjusted for demographic characteristics only, Q3 (OR: 0.74, 95% CI: 0.56-0.98, p = 0.036) and Q4 (OR: 0.70, 95% CI: 0.55-0.90, p = 0.006) had significant protective effects on sleep disorders. Additionally, gender subgroup analysis revealed that DFI had a significant impact on the female population, particularly in postmenopausal women, and was more pronounced in subjects with BMI > 30 kg/m2 (p = 0.011). Within the physical activity subgroup, there was a certain effect of DFI on improving sleep disorders in individuals with low activity intensity.

CONCLUSION

Increasing DFI had a protective effect in reducing the risk of sleep disorders. This protective effect may be more pronounced in the female population and individuals with low physical intensity.

Nightshift Rotation Schedule and Fatigue in U.K. and Italian Nurses

BACKGROUND

Whether hours on shift might impact adaptation to night shift work is still controversial.

METHODS

We conducted a pooled analysis of two studies, including 170 hospital nurses working night shifts, 116 from a United Kingdom study working 12-hour rotating shifts, and 54 from Italy working 8-hour shifts. Both studies used the Epworth Sleepiness Scale (ESS) to detect sleepiness during routine daytime activities as an indicator of fatigue. We compared the prevalence of daytime sleepiness, as indicated by an ESS score≥11, resulting from either shift work schedule. We used logistic regression to calculate the risk of daytime sleepiness associated with 12-hour vs. 8-hour nightshifts, adjusting by age, sex, and parenting children aged≤4.

RESULTS

When comparing similar work circumstances, nightshifts prolonged to 12 hours did not increase the risk of daytime sleepiness compared to 8 hours (OR=0.9, 95% CI 0.32, 2.59).

CONCLUSIONS

Our results suggest that 12-hour rotating nightshifts with additional rest days and 8-hour rotating shift schedules do not differ in their impact on daytime sleepiness. Further research is warranted on what strategies might effectively contrast fatigue, circadian misalignment, and the related metabolic changes leading to adverse health outcomes, including cancer.

Sleep Disorders

AbstractThere are more than 90 recognized sleep disorders, many of which impair sleep and daytime function and adversely impact heath, well-being, and chronic disease risk. Unfortunately, many sleep disorders are undiagnosed or not managed effectively. This review describes how to identify, evaluate, and treat common sleep disorders.

Association between Occupational Noise Exposure and Insomnia among Night-Shift Production Workers: A 4-Year Follow-up Study

Objectives

This study aimed to investigate whether occupational noise exposure is a risk factor for insomnia among male night-shift production workers.

Methods

This study followed 623 male night-shift production workers at a tire manufacturing factory without insomnia for 4 years. Insomnia was evaluated based on the insomnia severity index at baseline and at 4-year follow-up. A score of ≥15 was defined as insomnia. The higher occupational noise exposure group was defined as those individuals exposed to 8-hour time-weighted-average noise above 80 dB (A).

Results

Participants' mean age was 46.3 ± 5.6 years. Of the 623 participants, 362 (58.1%) were in the higher occupational noise exposure group. At 4-year follow-up, insomnia occurred in 3.2% (n = 20) of the participants. In a multiple logistic regression analysis, the odds ratio of insomnia was 3.36 (95% confidence interval 1.083-10.405, P = 0.036) in the higher occupational noise exposure group when compared with the lower noise exposure group after adjusting for confounders.

Conclusion

Our findings suggested that occupational noise exposure affected insomnia in male night-shift production workers. To prevent insomnia, efforts are required to reduce workplace noise exposure levels. Alternatively, moving to a less noisy work environment should be considered for workers with severe insomnia.

Shift work, clinically significant sleep disorders and mental health in a representative, cross-sectional sample of young working adults

Mental health conditions confer considerable global disease burden in young adults, who are also the highest demographic to work shifts, and of whom 20% meet criteria for a sleep disorder. We aimed to establish the relationship between the combined effect of shift work and sleep disorders, and mental health. The Raine Study is the only longitudinal, population-based birth cohort in the world with gold-standard, Level 1 measurement of sleep (polysomnography, PSG) collected in early adulthood. Participants (aged 22y) underwent in-laboratory PSG and completed detailed sleep questionnaires. Multivariable adjusted robust linear regression models were conducted to explore associations with anxiety (GAD7) and depression (PHQ9), adjusted for sex, health comorbidities, and work hours/week. Data were from 660 employed young adults (27.3% shift workers). At least one clinically significant sleep disorder was present in 18% of shift workers (day, evening and night shifts) and 21% of non-shift workers (p = 0.51); 80% were undiagnosed. Scores for anxiety and depression were not different between shift and non-shift workers (p = 0.29 and p = 0.82); but were higher in those with a sleep disorder than those without (Md(IQR) anxiety: 7.0(4.0-10.0) vs 4.0(1.0-6.0)), and depression: (9.0(5.0-13.0) vs 4.0(2.0-6.0)). Considering evening and night shift workers only (i.e. excluding day shift workers) revealed an interaction between shift work and sleep disorder status for anxiety (p = 0.021), but not depression (p = 0.96), with anxiety scores being highest in those shift workers with a sleep disorder (Md(IQR) 8.5(4.0-12.2). We have shown that clinical sleep disorders are common in young workers and are largely undiagnosed. Measures of mental health do not appear be different between shift and non-shift workers. These findings indicate that the identification and treatment of clinical sleep disorders should be prioritised for young workers as these sleep disorders, rather than shift work per se, are associated with poorer mental health. These negative mental health effects appear to be greatest in those who work evening and/or night shift and have a sleep disorder.

Gender Differences in Insomnia and Role of Work Characteristics and Family Responsibilities Among Healthcare Workers in Taiwanese Tertiary Hospitals

BACKGROUND

Insomnia is common among healthcare workers (HCWs), especially those working in tertiary hospitals. This study aimed to clarify whether gender differences in insomnia could be explained by gender differences in work characteristics and family responsibilities among HCWs in tertiary hospitals in Taiwan.

METHODS

This cross-sectional study was conducted in 22 departments of two tertiary hospitals in Northern Taiwan from December 2018 to March 2019. All data were obtained by a self-administered questionnaire given when participants underwent annual health check-ups. Insomnia was evaluated using the Chinese Athens Insomnia Scale. Work characteristics and family responsibilities were as follows: department, working hours, shift work, visual display terminals used at work, demand-control-support model, burnout level, breadwinner status, living conditions, and caregiver status. Data of 2,811 participants (317 men, 11.3%; 2,494 women, 88.7%) were analyzed (response rate: men, 85%; women, 88%). Logistic regression analysis examined howwork characteristics and family responsibilities explained gender differences in insomnia.

RESULTS

The prevalence of insomnia in women (61.7%) was significantly higher than that in men (52.7%), and gender differences strengthened after adjusting for work characteristics and family responsibilities [odds ratio: 1.45 (1.11-1.90) and 1.62 (1.18-2.22), p < 0.01]. Stratified analyses revealed that significant gender differences were found among HCWs with comparatively unfavorable work and family conditions. Furthermore, women had a higher association of insomnia owing to these factors.

CONCLUSION

These results suggest that gender differences in insomnia among HCWs are mainly explained by gender differences in work characteristics and family responsibilities.

How Is Work Ability Shaped in Groups of Shift and Non-Shift Workers? A Comprehensive Approach to Job Resources and Mediation Role of Emotions at Work

There is much less research on the relationship between shift work and positive states experienced in the workplace, e.g., emotions and work ability. Using the job demands-resources model, conservation of resources theory and the broaden-and-build theory as theoretical frameworks, the direct and indirect (mediated via positive and negative emotions) relations between the complex of job resources and work ability were tested in the group of shift and non-shift workers. Three types of resources related to task, leadership and interpersonal relations were taken into account. Data were collected among 1510 workers. Structural equation modelling (SEM) showed that only leadership was directly related to high work ability in both occupational groups. Indirect effects of positive and negative emotions were strongly supported. Both of them mediate the effects of the three analysed job resources on work ability, but individual job resources impacted were different. Leadership resources led to "good" work ability by the intensification of positive and reduction of negative emotions. Interpersonal resources decrease negative emotions. Task resources, conversely, intensified positive emotions, which in turn increased work ability. These research results shed more light on the ways of shaping work ability among shift and non-shift workers.