Working “out-of-phase” with reference to chronotype compromises sleep quality in police officers

Observational study to understand the effect of timing and regularity on sleep metrics and cardiorespiratory parameters using data from a smart bed

Sleep regularity and chronotype can affect health, performance, and overall well-being. This observational study examines how sleep regularity and chronotype affect sleep quality and cardiorespiratory metrics. Data was collected from 1 January 2019 through 30 December 2019 from over 330 000 Sleep Number smart bed users across the United States who opted into this at-home study. A pressure signal from the smart bed reflected bed presence, movements, heart rate (HR), and breathing rate (BR). Participants (mean age: 55.69 years [SD: 14.0]; 51.2% female) were categorized by chronotype (16.8% early; 62.2% intermediate, 20.9% late) and regularity of sleep timing. Participants who were regular sleepers (66.1%) experienced higher percent restful sleep and lower mean HR and BR compared to the 4.8% categorized as irregular sleepers. Regular early-chronotype participants displayed better sleep and cardiorespiratory parameters compared to those with regular late-chronotypes. Significant variations were noted in sleep duration (Cohen's d = 1.54 and 0.88, respectively) and restful sleep (Cohen's d = 1.46 and 0.82, respectively) between early and late chronotypes, particularly within regular and irregular sleep patterns. This study highlights how sleep regularity and chronotype influence sleep quality and cardiorespiratory metrics. Irrespective of chronotype, sleep regularity demonstrated a substantial effect. Further research is necessary to confirm these findings.

Gender and Nightshift Work: A Cross Sectional Study on Sleep Quality and Daytime Somnolence

A few studies suggested that female nightshift workers suffer more frequently from sleep deprivation and insomnia. We conducted a cross-sectional survey in two different occupational settings to address gender-related differences in nightshift work adaptation. We used the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index questionnaires to quantify daytime sleepiness and sleep quality among 156 workers, 91 from a ceramic tile factory and 65 healthcare workers, including hospital doctors, nurses, and nurse assistants. Seventy-three percent of participants (40 women and 74 men) were engaged in nightshift work. We used logistic regression analysis to predict daytime sleepiness and poor sleep quality as a function of personal and lifestyle variables and nightshift work. The female gender showed a strong association with both daytime sleepiness and poor sleep quality. Results were also suggestive of an increase in the risk of daytime sleepiness associated with nightshift work and being married. Our results confirm that women are especially vulnerable to sleep disruption. Promoting adaptation to nightshift work requires special attention towards gender issues.

Chronotype and Social Jetlag Influence Performance and Injury during Reserve Officers' Training Corps Physical Training

Sleep and circadian rhythms are critically important for optimal physical performance and maintaining health during training. Chronotype and altered sleep may modulate the response to exercise training, especially when performed at specific times/days, which may contribute to musculoskeletal injury. The purpose of this study was to determine if cadet characteristics (chronotype, sleep duration, and social jetlag) were associated with injury incidence and inflammation during physical training. Reserve Officers' Training Corps (ROTC) cadets (n = 42) completed the Morningness/Eveningness Questionnaire to determine chronotype, and 1-week sleep logs to determine sleep duration and social jetlag. Salivary IL-6 was measured before and after the first and fourth exercise sessions during training. Prospective injury incidence was monitored over 14 weeks of training, and Army Physical Fitness Test scores were recorded at the conclusion. Chronotype, sleep duration, and social jetlag were assessed as independent factors impacting IL-6, injury incidence, and APFT scores using ANOVAs, chi-squared tests, and the t-test where appropriate, with significance accepted at p < 0.05. Evening chronotypes performed worse on the APFT (evening = 103.8 ± 59.8 vs. intermediate = 221.9 ± 40.3 vs. morning = 216.6 ± 43.6; p < 0.05), with no difference in injury incidence. Sleep duration did not significantly impact APFT score or injury incidence. Social jetlag was significantly higher in injured vs. uninjured cadets (2:40 ± 1:03 vs. 1:32 ± 55, p < 0.05). Exercise increased salivary IL-6, with no significant effects of chronotype, sleep duration, or social jetlag. Evening chronotypes and cadets with social jetlag display hampered performance during morning APFT. Social jetlag may be a behavioral biomarker for musculoskeletal injury risk, which requires further investigation.

Prevalence of sleep disorders among first responders for medical emergencies: A meta-analysis

Background

Shift work and irregular work schedules among first responders have been associated with physical and psychological problems such as sleep disorders. We conducted the first meta-analysis to explore and estimate the prevalence of sleep disorders among first responders for medical emergencies.

Methods

We searched four databases: Web of Science, Psych Info, CINAHL, and PubMed. The Generalized Linear Mixed model (GLMM) was used to estimate the prevalence estimates of sleep disorders in R software and the DerSimonian-Lard random-effects model in Comprehensive Meta-Analysis was used to explore associated comorbidities for OSA and insomnia, presented as odds ratios (ORs) and confidence intervals (CIs). The Cochran's Q, τ², and the statistics were used to assess heterogeneity and the moderator analysis was conducted to identify moderator variables.

Results

Twenty-eight studies with 100 080 first responders were included from the total of 1119 studies retrieved from the databases. The prevalence rates for sleep disorders were 31% (95% CI = 15%-53%) for shift work disorder (SWD), 30% (95% CI = 18%-46%) for obstructive sleep apnea (OSA), 28% (95% CI = 19%-39%) for insomnia, 28% (95% CI = 24%-33%) for excessive daytime sleepiness (EDS), 2% (95% CI = 1%-4%) for restless leg syndrome, and 1% (95% CI = 0%-5%) for narcolepsy. Anxiety (OR = 2.46; 95% CI = 1.99%-3.03%), cardiovascular disease (CVD) (OR = 2.03; 95% CI = 1.43-2.88), diabetes mellitus (DM) (OR = 1.93; 95% CI = 1.41-2.65), depression (OR = 1.89; 95% CI = 1.01-3.56), gastroesophageal reflux disease (GERD) (OR = 1.83; 95% CI = 150-2.22), and post-traumatic stress disorder (PTSD) (OR = 1.78; 95% CI = 1.33-2.39) were associated with OSA. Depression (OR = 9.74; 95% CI = 4.67-20.3), anxiety (OR = 9.22; 95% CI = 3.81-22.3), and PTSD (OR = 7.13; 95% CI = 6.27-8.10) were associated with insomnia. Age, gender, first responders, continent, study quality, study design, and assessment tool were significant moderator variables for OSA, insomnia, and EDS.

Conclusions

This meta-analysis found a substantially high prevalence of sleep disorders including SWD, OSA, insomnia, and EDS among first responders for medical emergencies. Early assessment and management of sleep disorders among first responders is necessary to promote good, quality sleep to help prevent anxiety, depression, CVD, DM, GERD, and PTSD.

Do sleep quality and caffeine consumption mediate the relationship between late chronotype and body mass index?

AIM

To determine the role of sleep quality and caffeinated beverage consumption in the effect of late chronotype on body mass index (BMI).

MATERIALS AND METHODS

The study consisted of a total of 661 healthy university students with a mean age of 21.4 ± 1.38 years. Within the scope of the study, The Morningness-Eveningness Questionnaire (MEQ) was used to determine the chronotypes of individuals, the Pittsburgh Sleep Quality Index (PSQI) was used to determine sleep quality, and a 24 h physical activity record was taken to determine physical activity levels. The caffeine intake of the individuals was determined using a food frequency questionnaire for the intake of caffeinated food and beverages. The role of mediators in the effect of late chronotype on BMI was evaluated via multiple mediation analysis.

RESULTS

In this study, evening-type individuals had higher daily caffeine intake, worse sleep quality (P < 0.001), and higher BMI (P < 0.05). When the effect of mediators was taken into account, the negative relationship between the chronotype score and BMI was maintained (β = -0.109, 95% CI (-0.194, -0.021), P < 0.05). Decreased sleep quality had a mediated effect in this relationship [β = -0.208, 95% CI (-0.275, -0.119)], and caffeinated beverage consumption was found to have no mediator function (β = 0.040 95% CI (-0.050, 0.108), P > 0.05).

CONCLUSION

To conclude, eveningness chronotype had an effect on higher levels of caffeinated beverage consumption, lower sleep quality, and increased BMI. Chronotype, sleep quality, and caffeinated beverage consumption should be taken into account in studies examining the relationship between circadian rhythm and obesity.

Chronotype and depressive symptoms: A moderated mediation model of sleep quality and resilience in the 1st-year college students

OBJECTIVE

Depression is highly prevalent among 1st-year college students, and evening chronotype is an important risk factor associated with depression. This study investigates the mediating role of sleep quality and the moderating role of resilience between chronotype and depressive symptoms.

METHODS

A total of 4531 students were included in this cross-sectional study. Mediation and moderated mediation models were applied.

RESULTS

The association between chronotype and depressive symptoms was partially mediated by sleep quality, and the direct and indirect effects were moderated by resilience. The negative correlation between chronotype and depressive symptoms was significant in students with low levels of resilience compared with moderate/high levels. The positive correlation between sleep quality and depressive symptoms was strongest in low-level resilience students.

CONCLUSION

This study reveals that greater eveningness is associated with poorer sleep quality among 1st-year college students, which may lead to severer depression, and highlights the importance of resilience training in reducing depressive symptoms.

Sleep Quality, Sleep Structure, and PER3 Genotype Mediate Chronotype Effects on Depressive Symptoms in Young Adults

Depression and its related mood disorders are a major global health issue that disproportionately affects young adults. A number of factors that influence depressive symptoms are particularly relevant to the young adult developmental stage, including sleep loss, poor sleep quality, and the tendency toward eveningness in circadian preferences. However, relatively few studies have examined the relationship between sleep and circadian phenotypes, and their respective influences on mood, or considered potential molecular mechanisms driving these associations. Here, we use a multi-year, cross-sectional study of 806 primarily undergraduates to examine the relationships between sleep-wake chronotype, sleep disturbance, depression and genotypes associated with the PER3 variable number of tandom repeats (VNTR) polymorphism-circadian gene variants associated with both chronotype and sleep homeostatic drive. In addition, we use objective, Fitbit-generated sleep structure data on a subset of these participants (n = 67) to examine the relationships between chronotype, depression scores, actual measures of sleep duration, social jetlag, and the percent of deep and rapid eye movement (REM) sleep per night. In this population, chronotype is weakly associated with depressive symptoms and moderately correlated with self-reported sleep disturbance. Sleep disturbance is significantly associated with depression scores, but objective sleep parameters are not directly correlated with Beck Depression Inventory (BDI-II) scores, with the exceptions of a moderate correlation between social jetlag and depression scores in females and a marginal correlation between sleep duration and depression scores. Multiple regression and path analyses reveal that chronotype effects on depressive symptoms in this population are mediated largely by sleep disturbance. The PER3 VNTR genotype significantly predicts depressive symptoms in a model with objective sleep parameters, but it does not significantly predict depressive symptoms in a model with chronotype or subjective sleep disturbance. Interestingly, PER35,5 genotypes, in males only, are independently related to chronotype and depression scores. Our results support hypotheses linking subjective sleep quality and chronotype and provide a first step in understanding how objective sleep structure may be linked to chronotype and depressive symptoms. Our results also suggest that circadian gene variants may show sex-specific effects linking sleep duration and sleep structure to depression.

A systematic review of the current evidence regarding interventions for anxiety, PTSD, sleepiness and fatigue in the law enforcement workplace

Law enforcement is inherently stressful, and police officers are particularly vulnerable to mental and physical disorders. As such, researchers are currently assessing intervention strategies that may combat or manage these psychological, physical and mental issues. To review most recent information regarding anxiety, PTSD, and sleepiness and fatigue and identify the interventions and treatments proposed to overcome work related stressors and associated mental illnesses inflicting law enforcement officers. The EMBASE, OVID MEDLINE and PsycINFO databases were canvassed for articles investigating anxiety, post-traumatic stress disorder, sleepiness, and fatigue. Initial article selections were made based on title, whilst final inclusion was informed by a full critical appraisal with respect to the primary and secondary effects. The systematic search returned 363 records, of which 183 were unique. Following screening, 43 records were included in the final review. The included literature assessed the efficacy of several interventions, and provided a number of recommendations regarding interventions, and policy. Moreover, literature indicates that police officers benefit from interventions targeting work-related stress and potential psychological disorders, if these interventions are continuous. Furthermore, larger controlled studies are required to further elucidate the benefits of psychosocial intervention in law enforcement.

Sleep Quality among Police Officers: Implications and Insights from a Systematic Review and Meta-Analysis of the Literature

Poor sleep is associated with bad health outcomes, worse wellbeing and decreases in performance, productivity and safety at work. Police officers are exposed to several risk factors including extended work schedules, shift work, occupational stress, dangerous and traumatic events and can, as such, develop sleep problems. The aim of the present study was to analyze the sleep quality among police officers. A systematic literature search, in PubMed/MEDLINE, PsycINFO, Scopus, ISI/Web of Science (WoS) and the Cochrane Library was conducted. Original articles, published in English, French, Italian, Spanish and Portuguese, the primary objective of which was the evaluation of the quality of sleep through the Pittsburgh Sleep Quality Index (PSQI) in Police Forces, were selected. From an initial sample of 1,149 studies, 13 articles were included in the meta-analysis (3,722 police officers). The pooled prevalence of bad sleep quality in police officers was 51% [95%CI 42⁻60%]. The pooled global score of the PSQI was 5.6 [95%CI 5.0⁻6.3], corresponding to a low average quality. At the meta-regressions, statistically significant associations could be found for work seniority (in terms of years of service) and being on shift. The poor quality of sleep in police officers could have negative consequences for workers' health and for the safety of third parts. The implementation of health and sleep hygiene promotion programs in police forces is strongly recommended.

Identifying shift worker chronotype: implications for health

Shift workers are at risk for developing serious health issues due to short sleep. One cause of short sleep is circadian misalignment: sleep time is not synchronized with the body's natural circadian rhythms. Although circadian rhythms are strongly driven by the light/dark cycle, humans have individualized sleep time preferences (chronotypes) based on genetics, development, and external influences. Evening chronotype individuals fall asleep later than average and have a higher risk for developing various noncommunicable diseases. What is unclear is the association between chronotype, shift work, and risks for acquiring chronic conditions. This review is focused on shift worker chronotype and associations with obesity. Because of the paucity of research, other health issues connected with circadian misalignment were included, allowing for a total of 21 research studies. Evidence from this review supports chronotype and certain health issues are associated with shift work, even after adjusting for short sleep duration. In addition, there is evidence to support future research on how shift worker chronotype matched with shift timing impacts worker health. Through better understanding of this interface, occupational health providers can provide more comprehensive worker education on the risks associated with shift work and sleep disturbances.