Change in Job Strain as a Predictor of Change in Insomnia Symptoms: Analyzing Observational Data as a Non-randomized Pseudo-Trial

A narrative review of sleep and breast cancer: from epidemiology to mechanisms

Breast cancer is the leading cause of cancer-related death and the most common cancer among women worldwide. It is crucial to identify potentially modifiable risk factors to intervene and prevent breast cancer effectively. Sleep factors have emerged as a potentially novel risk factor for female breast cancer. Current epidemiologic studies suggest a significant impact of sleep factors on breast cancer. Exposure to abnormal sleep duration, poor sleep quality, sleep disorders, sleep medication use, or night shift work can increase the risk of breast cancer by decreasing melatonin secretion, disrupting circadian rhythm, compromising immune function, or altering hormone levels. However, there are still controversies regarding the epidemiologic association, and the underlying mechanisms have yet to be fully elucidated. This paper summarizes the epidemiologic evidence on the associations between sleep factors, including sleep duration, sleep quality, sleep disorders, sleep medication use, sleep habits, and night shift work, and the development of breast cancer. The potential mechanisms underlying these associations were also reviewed.

Physical activity and risk of workplace and commuting injuries: a cohort study

OBJECTIVE

Leisure-time physical activity (PA) has been hypothesized to reduce the likelihood of occupational injuries, but it is unclear whether this association varies between workplace and commuting injuries. The aim of this study was to examine the association between PA and risk of workplace and commuting injuries.

METHODS

Data were derived from the Finnish Public Sector study including 82 716 person-observations (48 116 participants). PA was requested repeatedly in four questionnaire surveys between 2000-2012. The average level of PA from two subsequent questionnaires was used to assess long-term PA. To obtain a 1-year incidence of injuries, participants were linked to occupational injury records from the national register. Logistic regression analysis with generalized estimating equations was used to examine the association between PA and injury risk. The analysis was adjusted for age, sex, education, work schedule, job demand, sleep difficulties, cardiovascular diseases, diabetes, and depression for workplace and commuting injuries, and workplace injuries were additionally adjusted for physical heaviness of an occupation and injury risk by occupation.

RESULTS

Higher level of PA was associated with a lower risk of workplace injuries compared to inactive participants [odds ratio (OR) 0.85, 95% confidence interval (CI) 0.73-0.98]. This association was most marked in the ≥50-year-old age group (OR 0.78, 95% CI 0.64-0.99). No association between the PA and the risk for commuting injuries was observed.

CONCLUSION

Higher PA is associated with lower risk of workplace injuries particularly among older employees.

Gene‒environment interaction effect of hypothalamic‒pituitary‒adrenal axis gene polymorphisms and job stress on the risk of sleep disturbances

Background

Studies have shown that chronic exposure to job stress may increase the risk of sleep disturbances and that hypothalamic‒pituitary‒adrenal (HPA) axis gene polymorphisms may play an important role in the psychopathologic mechanisms of sleep disturbances. However, the interactions among job stress, gene polymorphisms and sleep disturbances have not been examined from the perspective of the HPA axis. This study aimed to know whether job stress is a risk factor for sleep disturbances and to further explore the effect of the HPA axis gene × job stress interaction on sleep disturbances among railway workers.

Methods

In this cross-sectional study, 671 participants (363 males and 308 females) from the China Railway Fuzhou Branch were included. Sleep disturbances were evaluated with the Pittsburgh Sleep Quality Index (PSQI), and job stress was measured with the Effort-Reward Imbalance scale (ERI). Generalized multivariate dimensionality reduction (GMDR) models were used to assess gene‒environment interactions.

Results

We found a significant positive correlation between job stress and sleep disturbances (P < 0.01). The FKBP5 rs1360780-T and rs4713916-A alleles and the CRHR1 rs110402-G allele were associated with increased sleep disturbance risk, with adjusted ORs (95% CIs) of 1.75 [1.38-2.22], 1.68 [1.30-2.18] and 1.43 [1.09-1.87], respectively. However, the FKBP5 rs9470080-T allele was a protective factor against sleep disturbances, with an OR (95% CI) of 0.65 [0.51-0.83]. GMDR analysis indicated that under job stress, individuals with the FKBP5 rs1368780-CT, rs4713916-GG, and rs9470080-CT genotypes and the CRHR1 rs110402-AA genotype had the greatest risk of sleep disturbances.

Conclusions

Individuals carrying risk alleles who experience job stress may be at increased risk of sleep disturbances. These findings may provide new insights into stress-related sleep disturbances in occupational populations.

The relationship between psychosocial job stressors and insomnia: The mediating role of psychological capital

AIM

This study aimed to examine the association of job-related stressors and insomnia; to determine the association of psychological capital and insomnia; and to explore whether psychological capital mediates the association between job-related stressors and insomnia among Chinese nurses.

DESIGN

A cross-sectional questionnaire survey.

METHODS

The STROBE statement was utilized to guide the study. A total of 810 nurses from one tertiary grade hospital in Shan Dong Province, China, were recruited for the present study and a total of 658 valid questionnaires were obtained (effective recovery rate: 81.2%). The study survey consisted of demographic variables, psychological capital, job stress and insomnia. Descriptive analysis, independent-samples T-test, one-way analysis of variance, stratified regression analysis, Pearson correlation analyses, ordinary least-squares regression and the bootstrap method were used to analyse data.

RESULTS

Findings of the study determined that demographic, work-related, behavioural and work setting (i.e. working hours, chronic disease, negative life events, smoking behaviour and night shift) factors were differentially associated with experiences of insomnia. The empirical study showed that psychological capital had statistically significant mediating effects between job stressors and insomnia.

PUBLIC CONTRIBUTION

This study explored the factors associated with nurses' psychological job stressors and insomnia. Some of the associated factors could be used for the prevention and mitigation of psychosocial dysfunction among nurses. This study found nurses in surgery, emergency department, ICU, working >40 h a week, with chronic illness, experiencing negative life events, shift work and high effort, high overcommitment and low reward had higher scores of insomnia respectively. The results of this study also showed that reward was correlated with the increase of psychological capital, and the increase of psychological capital was correlated with the decrease of insomnia in nurses. On the contrary, effort and overcommitment decreased psychological capital, and then increased insomnia among nurses. These findings have important implications for future research and policy interventions to improve sleep quality of nurses and enhance nurses' health and patients' safety. This study significantly suggests that improving nurses' psychological capital is a potential way to help nurses improve sleep quality when psychosocial job stressors are difficult external environment to change.

Association of job stress, FK506 binding protein 51 (FKBP5) gene polymorphisms and their interaction with sleep disturbance

Background

Sleep disturbance is an outcome of multiple factors including environmental and genetic influences. Job stress, a complex environmental factor, likely affects sleep quality, significantly reducing the quality of life of workers. Additionally, FK506 binding protein 51 (FKBP5) may be a pathogenic factor for sleep disturbance as it regulates hypothalamic-pituitary-adrenal (HPA) axis activity, where HPA axis has been found to be involved in the regulation mechanism of sleep and stress response.

Objectives

The main aim of this study was to investigate the association between job stress and FKBP5 gene polymorphism as well as their interaction with sleep disturbance in Chinese workers; to date, these relationships have not been explored.

Methods

This is a cross-sectional study. A total of 675 railway workers (53.8% male) completed a short Effort-Reward Imbalance questionnaire and the Pittsburgh Sleep Quality Index. The SNaPshot single nucleotide polymorphism (SNP) assay was carried out by screening for FKBP5 SNPs in every participant. Generalized multifactor dimensionality reduction (GMDR) was used to identify the strongest G×E interaction combination.

Results

The findings showed that job stress was significantly associated with sleep disturbance; specifically, scores on the PSQI subscales (sleep disturbance, sleep medication, and daytime dysfunction) exhibited significant differences between the two job stress groups (X² = 18.10, p = 0.01). Additionally, the FKBP5 SNP rs1360780-TT (adjusted odds ratio [AOR] = 4.98, 95% confidence interval [CI] = 2.80-8.84) and rs3800373-CC genotype (AOR = 2.06, CI = 1.10-3.86) were associated with an increased risk of sleep disturbance. Job stress and rs1360780 and rs3800373 variants showed a high-dimensional interaction with sleep disturbance as determined by the GMDR model.

Conclusion

The FKBP5 gene may increase susceptibility to job stress and result in sleep disturbance, especially in the presence of negative work-related events. These findings contribute to the field of sleep disturbance prevention and treatment.

Association between sleep quality and occupational factors in Brazilian correctional officers

OBJECTIVE

To analyze the occupational factors associated with poor sleep quality in correctional officers (COs).

METHOD

This is a cross-sectional study involving COs who work at four prison facilities in the state of São Paulo, Brazil. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Logistic and linear regression models were used to calculate the odds ratio (OR) and beta coefficient (β) of poor sleep quality and the corresponding 95% confidence interval (CI), respectively. The analyses were adjusted for the main confounders.

RESULTS

Considering the 256 male COs who participated in the study, 148 (57.8%) had poor sleep quality. In the adjusted analyses, poor sleep quality was associated with higher mental demands (OR = 3.10; 95% CI: 1.40-6.85), having suffered psychological violence at work (OR = 2.13; 95% CI: 1.04-4.35), agreeing with the following statement: "I think about work-related issues in my free time" (OR = 5.13; 95% CI: 1.26-20.78), feeling partially dissatisfied (OR = 2.26; 95% CI: 1.09-4.68) or dissatisfied with work (OR = 4.52; CI: 1.32-15.46) and willingness to find another job (OR = 3.20; 95% CI: 1.53-6.71). The occupational factors dissatisfaction with work (β = 1.02; 95% CI: 0.05-1.98) and having health problems related to the work environment (β = 0.32; 95% CI: 0.24-2.41) were also associated with higher scores on the PSQI.

CONCLUSION

Poor quality of sleep is a highly frequent health problem among correctional officers, and this condition is associated with the perception of poor working conditions, professional dissatisfaction and the fact that such professionals think about work during their free time.

The Interplay Between Poor Sleep and Work-Related Health

Objectives

Sleep disorders can arise from work. Employees who experience work overload are more likely to develop sleep problems. Poor sleep leads to decreased performance, sick leave, and accidents. Therefore, sleep disorders may be linked to workplace hazards as well as decreased occupational health, however, the relationship remains unknown.

Methods

This relationship was examined using secondary data analysis of aggregated survey data from 97 companies based in Germany between 2003 and 2020 as part of Workplace Health Management project. Two extreme groups with respect to sleep problems were analyzed (N = 4,865 + 9,795). The survey “Diagnosis of corporate health” contained 137 individual questions which recorded all relevant working conditions, aspects of health, and one question relating to insomnia traits. A one-way analysis of variance was used to examine whether and to what extent the potentials, hazards, and health aspects differed between employees depending on their perceived sleep problems. In addition, multiple linear regressions were used to determine whether and to what extent work characteristics affect various health aspects for both good and poor sleepers.

Results

In total, 49.7% of staff reported moderate difficulty falling and/or remaining asleep. These poor sleepers perceived all health potentials worse than good sleepers, especially on scales such as fair assessment, work climate, and learning at work. Furthermore, poor sleepers perceived health hazards (physical environmental stress, job insecurity, and time pressure) more whilst positive health indicators (joy of work and confidence) were perceived less.

Conclusion

Overall, the determination of sleep difficulties could be used as a substantial health indicator. Also, these sleep problems are reported more frequently in certain occupations compared to others, which could mean that the perception of sleep health varies between professions. Therefore, it is important to implement specific recommendations for each industry in order to improve working conditions for poor sleepers which in turn, improves their health.

Effects of Work Stress and Period3 Gene Polymorphism and Their Interaction on Sleep Quality of Non-Manual Workers in Xinjiang, China: A Cross-Sectional Study

Work stress has been found to be associated with sleep quality in various occupational groups, and genetic factors such as variable number tandem repeat polymorphism in the Period3 (Per3) gene also influence the circadian sleep-wake process. Therefore, the present study aimed to evaluate the sleep quality status of non-manual workers in Xinjiang, China and to analyse the effects of work stress and Per3 gene polymorphism and their interaction on sleep quality. A cluster sampling method was used to randomly select 1700 non-manual workers in Urumqi, Xinjiang. The work stress and sleep quality of these workers were evaluated using the Effort−Reward Imbalance Inventory (ERI) and the Pittsburgh Sleep Quality Index (PSQI). Next, 20% of the questionnaire respondents were randomly selected for genetic polymorphism analysis. The polymerase chain reaction-restriction fragment length polymorphism technique was used to determine Per3 gene polymorphism. The detection rate of sleep quality problems differed between the different work stress groups (p < 0.05), suggesting that non-manual workers with high levels of work stress are more likely to have sleep quality problems. Regression analysis revealed that the Per3 gene (OR = 3.315, 95% CI: 1.672−6.574) was the influencing factor for poor sleep quality after adjusting for confounding factors, such as occupation, length of service, education, and monthly income. Interaction analysis showed that Per34/5,5/5 × high work stress (OR = 2.511, 95% CI: 1.635−3.855) had a higher risk of developing sleep quality problems as compared to Per34/4 × low work stress after adjusting for confounding factors. The structural equation modelling showed no mediating effect between work stress and Per3 gene polymorphism. The results of this study show that both work stress and Per3 gene polymorphism independently affect sleep quality of nonmanual workers from Xinjiang, and the interaction between these two factors may increase the risk of sleep quality problems. Therefore, to improve sleep quality, individuals with genetic susceptibility should avoid or reduce as much as possible self-stimulation by work-related exposures such as high levels of external work stress.

The relationship between occupational stressors and insomnia in hospital nurses: The mediating role of psychological capital

Background

Nurses have a high incidence of insomnia. Insomnia not only damages the physical and mental health of nurses, but also reduces their productivity and quality of care, ultimately affecting patient care. Over the past 30 years, a large number of epidemiological surveys have shown that insomnia in nurses is associated with occupational stress. As an external feature of the role of a nurse, occupational stress is difficult to alter in a short period of time. Therefore, it is necessary to discuss the complex mediating variables in the relationship between occupational stress and insomnia in nurses in order to find different ideas to address the problem of insomnia caused by occupational stress. Psychological capital, the positive psychological strength of an individual, has been widely used in previous reports as a mediating variable between occupational stress and adverse psychological problems.

Objective

This study aimed to explore the mediating effect of psychological capital on occupational stressors and insomnia among Chinese nurses.

Methods

The Strengthening the Reporting of Observational Studies in Epidemiology statement was referred to conduct the study. A cross-sectional stratified sampling method was used to recruit 720 participants from a tertiary hospital in Jinan, Shandong province, located in the east of China, from June to August 2019. Questionnaires were used to obtain data on demographic variables, psychological capital, occupational stressors, and insomnia.

Results

The study findings revealed that work settings [department (F = 3.08, p = 0.006), working hours per week (t = -2.03, p = 0.043) and shift work (t = 3.66, p < 0.001)], decision latitude (r = -0.25, p < 0.001), psychological job demand (r = 0.15, p < 0.001), social support (r = -0.31, p < 0.001), and psychological capital (r = -0.40, p < 0.001) were differentially associated with insomnia experiences. This cross-sectional survey showed that psychological capital has significant mediation effects on the relationship between occupational stressors and insomnia. In the model of decision latitude - psychological capital - insomnia, the mediating effect was-0.04 (95%CI: -0.07 ~ -0.02), accounting for 50.0% of the total effect; In the model of job demands - psychological capital - insomnia, the mediating effect was 0.03 (95%CI: 0.01 ~ 0.06), accounting for 25.0% of the total effect; In the model of social support - psychological capital - insomnia, the mediating effect was -0.11 (95%CI: -0.16 ~ -0.07), accounting for 39.0% of the total effect.

Conclusion

Psychological capital not only had a direct effect on both occupational stressors and insomnia, but also played mediating roles in relationship between occupational stressors and insomnia. It has been suggested that nurses themselves and nursing managers should improve the psychological capital of nurses by various means to alleviate the effects of occupational stress on nurses' insomnia.

The interaction of occupational stress, mental health, and cytokine levels on sleep in Xinjiang oil workers: A cross-sectional study

BACKGROUND

Sleep occupies one third of a person's life, and good sleep quality is an important factor to ensure good health.

PURPOSE

This study investigated and analyzed the occupational stress, mental health and sleep quality of oil workers, analyzed the effects of occupational stress and mental health on sleep, and explored the effects of the interaction between occupational stress, mental health and cytokines on sleep.

MATERIALS AND METHODS

In this study, stratified cluster random sampling was used to conduct a cross-sectional survey on the occupational stress, mental health and sleep quality of 1,141 oil workers in the Occupational Health Examination Department of Karamay Central Hospital, from June 2019 to January 2020, and 30% of the participants were randomly selected for measurement of their cytokine levels: interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor α (TNF-α). The objectives were to analyze the effects of occupational stress and mental health on sleep quality, and to explore the effects of occupational stress, mental disorders and cytokine interactions on sleep.

RESULTS

There were 646 individuals (56.6%) who suffered from sleep disorders; the incidence of sleep disorders differed according to sex, age, professional title, working years, type of work and shift (P < 0.05). The scores for occupational stress, mental health, and sleep quality were positively correlated (P < 0.05). Multivariate logistic regression analysis showed that age (30-45 years) (OR = 1.753, 95% CI: 1.067-2.881), junior college and above (OR = 1.473, 95% CI: 1.025-2.118), borehole operation (OR = 2.689, 95% CI: 1.508-4.792), extraction of oil (OR = 2.405, 95% CI: 1.229-4.705), drilling (OR = 1.791, 95% CI: 1.017-3.155), shift work (OR = 2.144, 95% CI: 1.615-2.846), occupational stress (OR = 1.007, 95% CI: 1.002-1.013), and mental disorders (OR = 1.020, 95% CI: 1.009-1.032) are risk factors for sleep disorders. In the high occupational stress group and the mental disorders group as the control group, the results showed that the interaction between IL-2 and moderate occupational stress (OR = 0.778, 95% CI: 0.778-0.942), IL-2 and non-mental disorders (OR = 0.398, 95% CI: 0.398-0.468) were protective factors for the occurrence of sleep disorders. The results of structural equation modeling analysis showed that occupational stress and mental health had positive predictive effects on IL-2 level and sleep quality [normalized path coefficients (β) were 0.10\0.06\0.05\0.71, respectively]. Occupational stress had a direct positive predictive effect on mental disorder (β = 0.25), and sleep disorder had a direct negative predictive effect on IL-2 concentration (β = -0.21).

CONCLUSION

Oil workers have serious sleep problems, so effective measures should be taken to reduce occupational stress and relieve mental health problems, and cytokine levels can be used as a predictor of sleep disorders.

Components of Stress and Their Associations with Sleep Problems: A Cohort Study of Older Employees

OBJECTIVE

To identify latent components from among 13 work and non-work stressors and to examine whether the accumulation of stress factors within these components was associated with sleep problems.

METHODS

A cohort of older employees (n = 2771 individuals, n = 3921 person-observations) responded to at least two surveys. Principal Component Analysis (PCA) was used to identify latent components. Analysis of variance was used to examine their associations with sleep.

RESULTS

The components were: 'Physical workload and shift work', 'Psychosocial workload', 'Social and environmental non-work adversity' and 'Life event- and health-related non-work adversity'. They were consistently associated with sleep problems, except for 'Physical workload and shift work'. 'Social and environmental non-work adversity' was associated with sleep problems at follow-up.

CONCLUSIONS

Clusters of work- and non-work-related stressors were identified, and their accumulation was associated with sleep problems among older employees.

Sleep duration and sleep difficulties as predictors of occupational injuries: a cohort study

STUDY OBJECTIVES

To examine the association between sleep duration and sleep difficulties with different types and causes of workplace and commuting injuries.

METHODS

The data were derived from the Finnish Public Sector study including 89.543 participants (178.309 person-observations). Participants reported their sleep duration and sleep difficulties between 2000 and 2012. These were linked to occupational injury records from the national register maintained by the Federation of Accident Insurance Institutions. Risk of injuries was followed up 1 year after each study wave. Logistic regression analysis with generalised estimating equations (GEEs) was used to examine the association between sleep duration/difficulties and risk of injuries, and multinomial logistic regression with GEE was used to examine the association with injury types and causes.

RESULTS

Both sleep duration and difficulties were associated with injuries. Employees with short sleep (≤6.5 hours) had 1.07-fold odds of workplace injuries (95% CI 1.00 to 1.14) and 1.14 times higher odds of commuting injuries (95% CI 1.04 to 1.26) compared with employees with normal sleep duration. For employees with disturbed sleep, the corresponding ORs were 1.09-fold (95% CI 1.02 to 1.17) and 1.14-fold (95% CI 1.04 to 1.26) compared with those without sleep difficulties, respectively. The risk of commuting injuries was higher among those who had difficulty in falling asleep (OR 1.29, 95% CI 1.07 to 1.55), woke up too early (OR 1.11, 95% CI 1.00 to 1.23) or had non-restorative sleep (OR 1.18, 95% CI 1.05 to 1.33).

CONCLUSIONS

Short sleep duration and sleep difficulties are associated with slightly increased risk of workplace and commuting injuries.

Association of job strain with accelerometer-based sleep duration and timing of sleep among older employees

Job strain has been associated with poor sleep quality and could lead to changes in duration and timing of sleep as well. This study examined the association of job strain with sleep duration, bedtimes and awakening times among public sector employees close to their retirement age. Differences in these sleep parameters between workdays and free days across job strain groups were examined. Duration and timing of sleep were measured repeatedly with accelerometers among 466 public sector employees in Finland (mean age 63 years, 86% women), who contributed to 759 measurements in total. Job demands (low/high) and control (low/high) measured by self-reports and job exposure matrix were used to identify low strain (low demand, high control), passive (low, low), active (high, high) and high strain (high, low) jobs. No differences in sleep duration were observed on workdays, whereas on free days those in the high strain group had longer sleep duration than those in the low strain and passive job groups. The high strain group also extended their sleep from workdays to free days more, the extension being on average 59 min (95% CI 42 min-75 min) when adjusted for several sociodemographic, work and health factors. This extension of sleep duration resulted mostly from a greater delay of awakening times from workdays to free days. Psychosocial work factors, such as job strain, need to be considered when promoting sufficient sleep duration among older employees, as those with job strain may have a greater need for recovery and sleep.

Association of occupational stress, period circadian regulator 3 (PER3) gene polymorphism and their interaction with poor sleep quality

Occupational stress is associated with sleep quality among workers and the human variable number tandem repeat (VNTR) polymorphism of the period circadian regulator 3 (PER3) gene relates to sleep-wake regulation. The main aims of the present study were to examine the effects of PER3 VNTR genotypes, occupational stress, and their interactions on sleep quality. A cross-sectional study was conducted and 729 workers were recruited in Sichuan. Sleep quality were assessed using the Pittsburgh Sleep Quality Index. Occupational stress was measured using the Generic Job Stress Questionnaire. PER3 genotypes were determined with polymerase chain reaction. High and medium occupational stress were linked to a higher risk of poor sleep quality than low levels. Unconditional logistic regression indicated that PER3 genotype was significantly associated with sleep quality, and an increased risk of poor sleep of >1.5-times was observed in those with the allele 5 compared to allele 4. The 5/5 genotype was associated with both sleep latency and sleep duration. Crossover analysis showed an occupational stress × PER3 interaction. Compared to subjects with both low and medium occupational stress and 4/4 + 4/5 genotype, those with both high occupational stress and 5/5 genotype had a higher risk of poor sleep quality. Stratified logistic analyses found that compared with low and medium occupational stress, high occupational stress increased the risk of poor sleep by more than five-times in 5/5 genotype carriers. Occupational stress and PER3 genotype had both separate and combined effects on poor sleep quality of workers. The results suggest that occupational stress may increase the risk of poor sleep quality through interaction with the PER3 gene polymorphism.

The relationship between onset of workplace violence and onset of sleep disturbances in the Swedish working population

The study investigated the association between onset of workplace violence and onset of sleep disturbances. We used self-reported data from the Swedish Longitudinal Occupational Survey of Health (SLOSH) collected in 2014, 2016, and 2018. A two-wave design was based on participants who had no exposure to workplace violence or sleep disturbances at baseline (n = 6,928). A three-wave design was based on participants who in addition were unexposed to sleep disturbances in the second wave (n = 6,150). Four items of the Karolinska Sleep Questionnaire were used to measure sleep disturbances and one question was used to measure the occurrence of workplace violence or threats of violence. Multivariate logistic regression analyses were performed. In the two-wave approach, onset of workplace violence was associated with onset of sleep disturbances after adjustment for sex, age, occupational position, education, and civil status (adjusted odds ratio 1.41, 95% confidence interval 1.02-1.96). The association was no longer statistically significant after further adjustment for night/evening work, demands, control, and social support at work. In the three-wave approach, results were only suggestive of an association between onset of workplace violence and subsequent onset of sleep disturbances after adjustment for sex, age, occupational position, education, and civil status. Onset of frequent exposure to workplace violence was associated with subsequent onset of sleep disturbances in the adjusted analyses, but these analyses were based on few individuals (13 exposed versus 5,907 unexposed). The results did not conclusively demonstrate that onset of workplace violence predicts development of sleep disturbances. Further research could elucidate the role of other working conditions.

The Different Faces of Insomnia

Objectives: The identification of clinically relevant subtypes of insomnia is important. Including a comprehensive literature review, this study also introduces new phenotypical relevant parameters by describing a specific insomnia cohort. Methods: Patients visiting the sleep center and indicating self-reported signs of insomnia were examined by a sleep specialist who confirmed an insomnia diagnosis. A 14-item insomnia questionnaire on symptoms, progression, sleep history and treatment, was part of the clinical routine. Results: A cohort of 456 insomnia patients was described (56% women, mean age 52 ± 16 years). They had suffered from symptoms for about 12 ± 11 years before seeing a sleep specialist. About 40-50% mentioned a trigger (most frequently psychological triggers), a history of being bad sleepers to begin with, a family history of sleep problems, and a negative progression of insomnia. Over one third were not able to fall asleep during the day. SMI (sleep maintenance insomnia) symptoms were most frequent, but only prevalence of EMA (early morning awakening) symptoms significantly increased from 40 to 45% over time. Alternative non-medical treatments were effective in fewer than 10% of cases. Conclusion: Our specific cohort displayed a long history of suffering and the sleep specialist is usually not the first point of contact. We aimed to describe specific characteristics of insomnia with a simple questionnaire, containing questions (e.g., ability to fall asleep during the day, effects of non-medical therapy methods, symptom stability) not yet commonly asked and of unknown clinical relevance as yet. We suggest adding them to anamnesis to help differentiate the severity of insomnia and initiate further research, leading to a better understanding of the severity of insomnia and individualized therapy. This study is part of a specific Research Topic introduced by Frontiers on the heterogeneity of insomnia and its comorbidity and will hopefully inspire more research in this area.

Analysis of the evidence of related factors, associated conditions and at-risk populations of the NANDA-I nursing diagnosis insomnia

Objectives

To summarize evidence in the literature on the predictors of insomnia in adults and to determine correspondences with diagnostic indicators of the NANDA-I diagnosis Insomnia.

Methods

An integrative review performed in Pubmed, Virtual Health Library and CINAHL. Forty-eight articles published in Portuguese, English or Spanish from 2011 to 2018 were included. An analysis of correspondence between the predictors and the NANDA-I related factors and associated conditions for Insomnia was performed.

Results

There was a correspondence of the predictors found in this review with NANDA-I related factors and associated conditions, except for grieving and frequent naps during the day. Smoking, caffeine intake, dysfunctional sleep beliefs, obesity and caregiver role strain are possible new related factors; chronic illness is a possible new associated condition and individuals going through changes in marital status, economically disadvantaged, female gender, increasing age and night shift worker are possible new at-risk populations.

Conclusion

The predictors of insomnia that had a correspondence with the NANDA-I elements can support the evidence base of the nursing diagnosis. The predictors found without a correspondence with the diagnosis can be considered for inclusion in the NANDA-I classification, thereby supporting the clinical reasoning of nurses and students.

Concurrent changes in sleep and physical activity during the transition to retirement: a prospective cohort study

BACKGROUND

Currently, little is known regarding whether changes in physical activity are associated with changes in sleep in general population. The aim of this study was to examine the association between changes in physical activity and changes in sleep duration and difficulties at retirement transition point.

METHODS

Data from the prospective Finnish Retirement and Aging study of 2745 retired public sector employees was used. Participants answered questionnaires before and after the retirement with one year interval, in which they reported average weekly hours of physical activity, sleep duration and the frequency of sleep difficulties. The level of physical activity, classified as 'low', 'moderate' or 'high', before and after retirement was used to classify the participants to five physical activity groups. Changes in sleep duration (in minutes) and sleep difficulties (no, moderate, severe) were examined in these physical activity groups.

RESULTS

Before retirement, high physical activity was associated with longest sleep duration (7 h 8 min) and low physical activity was associated with severe sleep difficulties (OR 1.23, 95% CI 1.06-1.44) in comparison to high physical activity. During retirement transition, sleep duration increased in all physical activity change groups and sleep difficulties decreased significantly in 'stable', 'increase from moderate', 'decrease from moderate' and 'decrease from high' groups. Changes in sleep duration and sleep difficulties were not statistically significantly different between the physical activity change groups.

CONCLUSION

Sleep duration increases and sleep difficulties decrease after retirement. Changes in sleep during retirement transition seem to be independent of changes in physical activity during the same time period.

Reciprocal relations between work stress and insomnia symptoms: A prospective study

Work stress and poor sleep are closely related in cross-sectional data, but evidence from prospective data is limited. We analysed how perceived stress and work stressors (work demands, decision authority and workplace social support) are related to key dimensions of insomnia over time, using structural equation modelling. Biennial measurements from a large sample of the working population in Sweden enabled us to analyse both the relationship from stress to sleep as well as that from sleep to stress. Overall, we found reciprocal relations between insomnia and all four stress measures. However, looking at the relation between each dimension of insomnia and each stress measure, there were some differences in direction of effects. In the direction from stress to sleep, all work stressors as well as perceived stress predicted both difficulties initiating sleep and difficulties maintaining sleep. The same was found for non-restorative sleep, with the exception for decision authority. In the opposite direction, difficulties maintaining sleep predicted increased levels of work demands and perceived stress. Difficulties initiating sleep stood out among the insomnia symptoms as not predicting any of the stress measures, while non-restorative sleep was the only symptom predicting all stress measures. The results advance the understanding of the stress-sleep relationship and indicate a potential vicious circle between insomnia and perceived stress as well as work stressors, suggesting that the workplace could be an arena for interventions to alleviate insomnia.

Cross-Sectional Survey on the Relationship Between Occupational Stress, Hormone Levels, and the Sleep Quality of Oilfield Workers in Xinjiang, China

The impact of psychosocial factors on health has received increased attention. This study employed a multi-stage hierarchical cluster sampling method and a cross-sectional survey was conducted from March to August 2017. By studying 2116 oilfield workers based in Karamay, Xinjiang, the relationship between occupational stress, blood hormone levels, and sleep was analyzed. Occupational stress was measured using the internationally accepted Occupational Stress Inventory Revised Edition (OSI-R) questionnaire and sleep disorders were measured using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. The study found that the sleep quality of respondents was not high and the incidence of sleep disorders was 36.67%. The higher the level of occupational stress, the higher the incidence of sleep disorders. Irregular shifts can affect sleep quality and individuals with high-level professional titles experience a higher incidence of sleep disorders than those with low-level titles. The total score of the PSQI was different among the low, medium, and high stress groups. The higher the level of stress, the higher the scores of subjective sleep quality, sleep disorder, and daytime dysfunction. The scores of the PSQI, subjective sleep quality, sleep time, sleep disturbance, and daytime dysfunction in the high-stress group were higher than those in the low stress group. A case-control study found that the concentration of glucocorticoids in the sleep disorder positive group was lower than that in the sleep disorder negative group. The results of the regression analysis showed that glucocorticoid is a protective factor for sleep disorders (OR = 0.989, 95% CI: 0.983-0.995), suggesting that the higher the level of glycosaminoglycan, the less likely the subject is to have sleep disorders. For example, in the case of high occupational stress, the interaction between low and moderate occupational stress levels and glucocorticoids is a protective factor for sleep disorders.

Association of change in cognitive function from early adulthood to middle age with risk of cause-specific mortality: the Vietnam Experience Study

BACKGROUND

Studies with single baseline measurements of cognitive function consistently reveal inverse relationships with mortality risk. The relation of change in functioning, particularly from early in the life course, which may offer additional insights into causality, has not, to the best of our knowledge, been tested.

AIMS

To examine the association of change in cognition between late adolescence and middle age with cause-specific mortality using data from a prospective cohort study.

METHODS

The analytical sample consisted of 4289 former US male military personnel who were administered the Army General Technical Test in early adulthood (mean age 20.4 years) and again in middle age (mean age 38.3 years).

RESULTS

A 15-year period of mortality surveillance subsequent to the second phase of cognitive testing gave rise to 237 deaths. Following adjustment for age, a 10-unit increase in cognitive function was related to a reduced risk of death from all causes (HR 0.84; 95% CI 0.75 to 0.93) and cardiovascular disease (HR 0.78; 95% CI 0.64 to 0.95) but not from all cancers (HR 1.14; 95% CI 0.88 to 1.47) nor injury (HR 1.02; 95% CI 0.81 to 1.29). Adjustment for markers of socioeconomic status in middle age resulted in marked attenuation in the magnitude of these associations and statistical significance at conventional levels was lost in all analyses.

CONCLUSIONS

In the present study, the apparent link between increased cognition and mortality was mediated by socioeconomic status.

Reduction in sleep disturbances at retirement: evidence from the Swedish Longitudinal Occupational Survey of Health

Although retirement involves a radical change in daily activities, income, social roles and relationships, and the transition from paid work into retirement can, therefore, be expected to affect sleep, little is known about the effects of old-age retirement on changes in sleep disturbances, and how the impact of retirement may vary by gender, age and prior working conditions. This study modelled reported sleep disturbances up to nine years before to nine years following retirement in a sample of 2,110 participants from the Swedish Longitudinal Occupational Survey of Health (SLOSH). Sleep disturbances over the retirement transition were modelled using repeated-measures regression analysis with Generalized Estimating Equations (GEE) in relation to gender, age at retirement, working patterns (night work, full-time/part-time work), control over work hours, and psychological and physical working conditions. The analyses controlled for civil status, education level, income obtained from registers and self-rated health. Retiring from paid work was associated with decreased sleep disturbances. Greater reductions in sleep disturbances were reported by women, as well as by participants who retired before age 65 years, who were working full-time, who lacked control over their work hours and who had high psychological demands. These results, suggesting that old-age retirement from paid work is associated with reductions in disturbed sleep, pose a challenge for governments seeking to increase retirement ages.

Sleep and Sleep Disorders in the Menopausal Transition

The menopausal transition is associated with an increase in insomnia symptoms, especially difficulty staying asleep, which negatively impacts quality of life. Vasomotor symptoms are a key component of sleep disruption. Findings from polysomnographic studies are less consistent in showing disrupted sleep in menopausal transition independent of aging; further prospective studies are needed. Hormone therapy alleviates subjective sleep disturbances, particularly if vasomotor symptoms are present. However, because of contraindications, other options should be considered. Further work is needed to develop preventive and treatment strategies for alleviating sleep disturbances to ensure better health, quality of life, and productivity in midlife women.

A decade's difference: 10-year change in insomnia symptom prevalence in Canada depends on sociodemographics and health status

INTRODUCTION

Insomnia is recognized as a public health issue. The objectives of this study were to characterize and compare the prevalence of insomnia symptoms in the Canadian population in 2002 and 2012, and to identify sociodemographic and psychosocial predictors of trouble sleeping.

METHODS

Data from adult participants in the Canadian Community Health Survey-Mental Health cycles 2000-2002 (n = 34,118) and 2011-2012 (n = 23,089) were used. Participants responded to the question "How often do you have trouble going to sleep or staying asleep?", with those who indicated "most of the time" or "all of the time" classified as having insomnia symptoms. Logistic regressions, adjusted for covariates, were used to examine differences between cycles.

RESULTS

The unadjusted prevalence of insomnia symptoms increased from 15.6% to 17.1% between 2002 and 2012, representing an absolute increase of 1.5%. The likelihood of insomnia symptoms was significantly influenced by age, sex, education, physical health, and mental health status. A 3-way year-age-sex interaction was statistically significant such that women aged 40-59 demonstrated approximately 29% increased likelihood of insomnia symptoms from 2002 to 2012. This was reduced to 24% when adjusted for physical and mental health. There were no significant differences for men across age groups.

CONCLUSION

Over a 10-year period, the prevalence of insomnia symptoms increased in Canada. This trend appears to be driven in part by greater levels of insomnia symptoms among middle-aged women.

Changes in psychosocial and physical working conditions and psychotropic medication in ageing public sector employees: a record-linkage follow-up study

OBJECTIVES

To investigate whether changes in psychosocial and physical working conditions are associated with subsequent psychotropic medication in ageing employees.

METHODS

Data were from the Helsinki Health Study, a cohort study of Finnish municipal employees, aged 40-60 years at phase 1 (2000-2002). Changes in psychosocial and physical working conditions were measured between phase 1 and phase 2 (2007). Survey data were longitudinally linked to data on prescribed, reimbursed psychotropic medication purchases (Anatomical Therapeutic Chemical) obtained from the registers of the Social Insurance Institution of Finland between the phase 2 survey and December 2013 (N=3587; 80% women). Outcomes were any psychotropic medication; antidepressants (N06A); anxiolytics (N05B); and sedatives and hypnotics (N05C). Cox regression analyses were performed.

RESULTS

During the follow-up, 28% of the participants were prescribed psychotropic medication. Repeated exposures to low job control, high job demands and high physical work load were associated with an increased risk of subsequent antidepressant and anxiolytic medication. Increased and repeated exposure to high physical work load, increased job control and repeated high job demands were associated with subsequent sedative and hypnotic medication. Age and sex-adjusted HR varied from 1.18 to 1.66. Improvement in job control was associated with a lower risk of anxiolytic, but with a higher risk of sedatives and hypnotic medication. Decreased physical work load was associated with a lower risk of antidepressant and anxiolytic medications.

CONCLUSION

Improvement in working conditions could lower the risk of mental ill-health indicated by psychotropic medication.