The role of driver sleepiness in car crashes: a systematic review of epidemiological studies

Presenteeism and Traffic Accident Among Taxi Drivers: A Prospective Cohort Study in Japan

Background

Traffic accidents involving professional drivers have serious societal repercussions. Unique occupational stressors and health risks exacerbate the likelihood of traffic accidents among professional drivers. This study explores the association between presenteeism-impaired work performance due to working while unwell-and traffic accident risk among professional taxi drivers in Japan.

Methods

A prospective cohort study was conducted from June 2022 to February 2023, involving taxi drivers from a single company in Fukuoka Prefecture, Japan. Presenteeism was assessed using the Work Functioning Impairment Scale (WFun). Primary outcome involved the number of self-reported minor traffic accidents. The incidence rate ratio (IRR) of minor traffic accident occurrences was estimated using a Poisson regression analysis, adjusted for confounders including sex, age, and driving experience.

Results

Of 838 targeted drivers, 435 were included in the analysis. Higher baseline work functioning impairment was associated with a significant trend of increasing IRR of minor traffic accidents (p for trend = 0.045). A dose-response relationship was seen between the degree of presenteeism and incidence rate of minor traffic accidents.

Conclusion

Higher levels of presenteeism were associated with an increased risk of traffic accidents among taxi drivers. The findings underscore the need for socio-economic support and prioritized health management to mitigate traffic accident risk among professional drivers. This study highlights the importance of managing non-critical health issues alongside serious health conditions for safer driving practices among professional drivers in Japan.

Advancing a U.S. navy shipboard infrastructure for sleep monitoring with wearable technology

Development of fatigue management solutions is critical to U.S. Navy populations. This study explored the operational feasibility and acceptability of commercial wearable devices (Oura Ring and ReadiBand) in a warship environment with 845 Sailors across five ship cohorts during at-sea operations ranging from 10 to 31 days. Participants were required to wear both devices and check-in daily with research staff. Both devices functioned as designed in the environment and reliably collected sleep-wake data. Over 10,000 person-days at-sea, overall prevalence of Oura and ReadiBand use was 69% and 71%, respectively. Individual use rates were 71 ± 38% of days underway for Oura and 59 ± 34% for ReadiBand. Analysis of individual factors showed increasing device use and less device interference with age, and more men than women found the devices comfortable. This study provides initial support that commercial wearables can contribute to infrastructures for operational fatigue management in naval environments.

Development and evaluation of a scale to measure nurses' unsafe driving behaviour while commuting

Driving is the most prevalent form of commuting for most workers but is also perhaps the most hazardous mode of travel with unsafe driving contributing significantly to road traffic accidents. Despite nurses having been reported as being at higher risk of commuter-related accidents over the last three decades, little is known about unsafe driving behaviours among nurses while commuting, which is unique from other driving routines. Additionally, the lack of appropriate tools to measure such behaviours is apparent. This study aims i) to identify unsafe driving behaviours among nurses while commuting and ii) to develop a scale to assess nurses' unsafe commuting driving behaviours. The study employed a multiphase and multimethod approach to develop the scale, which was subject to stringent validation and evaluation. Themes were specified via the Nominal Group Technique (NGT). Six themes were identified namely: i) violations and reckless driving, ii) negative emotions, iii) drowsy driving iv) mind wandering, v) error and vi) carelessness. Content and face validity were sought through expert review. A total of 442 nurses' data were collected across multisite hospitals for evaluation. Exploratory factor analysis (EFA) resulted in recovered structure and was confirmed through Confirmatory Factor Analysis (CFA) with structural equation analyses being conducted to test predictive validity. All constructs met adequate validity and reliability. Nurses' unsafe driving behaviours while commuting were identified with a novel scale to assess them being both developed and validated. The resulting MyUDWC scale is a suitable tool for measuring nurses' unsafe driving behaviours while commuting.

The firstly visited department affects the acceptance of CPAP in patients with obstructive sleep apnea: a cohort study

BACKGROUND

Continuous positive airway pressure (CPAP) therapy is the first-line treatment for obstructive sleep apnea (OSA). However, the low acceptance rate of CPAP remains a challenging clinical issue. This study aimed to determine the factors that influence the acceptance rate of CPAP.

METHODS

This retrospective cohort study was conducted at the sleep center of Shuang-Ho Hospital. Initially, 1186 OSA patients who received CPAP therapy between December 2013 and December 2017 were selected, and finally, 1016 patients were analyzed. All patients with OSA received CPAP therapy for at least 1 week, and their acceptance to treatment was subsequently recorded. Outcome measures included patients' demographic and clinical characteristics (sex, age, BMI, comorbidities, history of smoking, and the medical specialist who prescribed CPAP treatment), polysomnography (PSG) results, and OSA surgical records.

RESULTS

Patients with a lower CPAP acceptance rate were referred from otolaryngologists (acceptance rate of otolaryngology vs. others: 49.6% vs. 56.6%, p = .015), in addition to having a lower apnea-hypopnea index (AHI) (acceptance vs. non-acceptance: 55.83 vs. 40.79, p = .003), rapid eye movement AHI (REM-AHI) (acceptance vs. non-acceptance: 51.21 vs. 44.92, p = .014), and arousal index (acceptance vs. non-acceptance: 36.80 vs. 28.75, p = .011). The multiple logistic regression model showed that patients referred from otolaryngology had a lower CPAP acceptance rate (odds ratio 0.707, p = .0216) even after adjusting for age, sex, BMI, AHI, REM-AHI, arousal index, comorbidities, and smoking status.

CONCLUSIONS

Before their initial consultation, patients may already have their preferred treatment of choice, which is strongly linked to the type of medical specialists they visit, and consequently, affects their rate of acceptance to CPAP therapy. Therefore, physicians should provide personalized care to patients by exploring and abiding by their preferred treatment choices.

Generating consensus on road safety issues and priorities in Ghana: A modified Delphi approach

BACKGROUND

Implementation of evidence-based approaches to reduce the substantial health, social, and financial burdens of road traffic injuries and deaths in Ghana and other low-and-middle-income countries (LMICs) is vitally important. Consensus from national stakeholders can provide insight into what evidence to generate and which interventions to prioritize for road safety. The main objective of this study was to elicit expert views on the barriers to reaching international and national road safety targets, the gaps in national-level research, implementation, and evaluation, and the future action priorities.

MATERIALS AND METHODS

We used an iterative three-round modified Delphi process to generate consensus among Ghanaian road safety stakeholders. We defined consensus as 70% or more stakeholders selecting a specific response in the survey. We defined partial consensus (termed "majority") as 50% or more stakeholders selecting a particular response.

RESULTS

Twenty-three stakeholders from different sectors participated. Experts generated consensus on barriers to road safety goals, including the poor regulation of commercial and public transport vehicles and limited use of technology to monitor and enforce traffic behaviors and laws. Stakeholders agreed that the impact of increasing motorcycle (2- and 3-wheel) use on road traffic injury burden is poorly understood and that it is a priority to evaluate road-user risk factors such as speed, helmet use, driving skills, and distracted driving. One emerging area was the impact of unattended/disabled vehicles along roadways. There was consensus on the need for additional research, implementation, and evaluation efforts of several interventions, including focused treatment of hazardous spots, driver training, road safety education as part of academic curricula, promotion of community involvement in first aid, development of strategically positioned trauma centers, and towing of disabled vehicles.

CONCLUSION

This modified Delphi process with stakeholders from Ghana generated consensus on road safety research, implementation, and evaluation priorities.

The EEG correlates and dangerous behavioral consequences of drowsy driving after a single night of mild sleep deprivation

OBJECTIVE

Here, we investigated the behavioral, cognitive, and electrophysiological impact of mild, acute sleep loss via simultaneously recorded behavioral and electrophysiological measures of vigilance during a "real-world", simulated driving task.

METHODS

Participants (N = 34) visited the lab for two testing days where their brain activity and vigilance were simultaneously recorded during a driving simulator task. The driving task lasted approximately 70 mins and consisted of tailgating the lead car at high speed, which braked randomly, requiring participants to react quickly to avoid crashing. The night before testing, participants either slept from 12am-9am (Normally Rested), or 1am-6am (Sleep Restriction).

RESULTS

After a single night of mild sleep restriction, sleepiness was increased, participants took longer to brake, missed more braking events, and crashed more often. Brain activity showed more intense alpha burst activity and significant changes in EEG spectral power frequencies related to arousal (e.g., delta, theta, alpha). Importantly, increases in amplitude and number of alpha bursts predicted delays in reaction time when braking.

CONCLUSIONS

The findings of this study suggest that a single night of mild sleep loss has significant, negative consequences on driving performance and vigilance, and a clear impact on the physiology of the brain in ways that reflect reduced arousal.

SIGNIFICANCE

Understanding neural and cognitive changes associated with sleep loss may lead to important advancements in identifying and preventing potentially dangerous sleep-related lapses in vigilance.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared in order to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Because sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Sleep Difficulties Among COVID-19 Frontline Healthcare Workers

OBJECTIVE

To identify COVID-19 work-related stressors and experiences associated with sleep difficulties in HCW, and to assess the role of depression and traumatic stress in this association.

METHODS

A cross-sectional study of HCW using self-report questionnaires, during the first peak of the pandemic in Israel (April 2020), conducted in a large tertiary medical center in Israel. Study population included 189 physicians and nurses working in designated COVID-19 wards and a comparison group of 643 HCW. Mean age of the total sample was 41.7 ± 11.1, 67% were female, 42.1% physicians, with overall mean number of years of professional experience 14.2 ± 20. The exposure was working in COVID-19 wards and related specific stressors and negative experiences. Primary outcome measurement was the Insomnia Severity Index (ISI). Secondary outcomes included the Primary Care-Post Traumatic Stress Disorder Screen (PC-PTSD-5); the Patient Health Questionnaire-9 (PHQ-9) for depression; the anxiety module of the Patient-Reported Outcomes Measurement Information System (PROMIS); Pandemic-Related Stress Factors (PRSF) and witnessing patient suffering and death.

RESULTS

Compared with non-COVID-19 HCW, COVID-19 HCW were more likely to be male (41.3% vs. 30.7%) and younger (36.91 ± 8.81 vs. 43.14 ± 11.35 years). COVID-19 HCW reported higher prevalence of sleep difficulties: 63% vs. 50.7% in the non-COVID group (OR 1.62, 95% CI 1.15-2.29, p = 0.006), mostly difficulty maintaining sleep: 26.5% vs. 18.5% (OR 1.65, 95% CI 1.11-2.44, p = 0.012). Negative COVID-19 work-related experiences, specifically witnessing patient physical suffering and death, partially explained the association. Although past psychological problems and current depression and PTSD were associated with difficulty maintaining sleep, the main association remained robust also after controlling for those conditions in the full model.

CONCLUSION AND RELEVANCE

COVID-19 frontline HCW were more likely to report sleep difficulties, mainly difficulty maintaining sleep, as compared with non-COVID-19 HCW working at the same hospital. Negative patient-care related experiences likely mediated the increased probability for those difficulties. Future research is needed to elucidate the long-term trajectories of sleep difficulties among HCW during large scale outbreaks, and to identify risk factors for their persistence.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Since sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Association between sleep disturbance and occupational injury among Korean employees

Background

Occupational injury has been a serious social problem steadily. Sleep disturbance is a risk factor for occupational injury. However, there were few researches studied on the linking between sleep disturbance and occupational injury in general working population of Korea. Therefore, we explored the association between sleep disturbance and occupational injury among Korean workers.

Methods

This study used data from the 5th Korean Working Conditions Survey. Occupational injury was assessed by asking work related injury for 12 months prior to the point of the survey. Sleep disturbance was assessed using the Minimal Insomnia Symptoms Scale (MISS). To analyze the association between sleep disturbance and occupational injury, multiple logistic regression analysis was conducted.

Results

The odds ratio (OR) of sleep disturbance group for occupational injury was 2.57 (95% confidence interval [CI]: 1.68–3.93) in the fully adjusted model. For the association between MISS score and occupational injury, it showed increasing trend that ORs increase from the 1st to the 4th quartiles. The OR of 2nd quartile was 1.10 (95% CI: 0.60–2.01), the OR of 3rd quartile was 2.27 (95% CI: 1.53–3.38) and the OR of 4th quartile was 2.80 (95% CI: 1.84–4.26).

Conclusions

Sleep disturbance was associated with occupational injury. In addition, increasing trend was observed between MISS score and occupational injury. These findings imply that developing of intervention programs to manage sleep disturbance and fatigue may be necessary to prevent occupational injury.

Comparing objective wakefulness and vigilance tests to on-the-road driving performance in narcolepsy and idiopathic hypersomnia

Patients with narcolepsy or idiopathic hypersomnia (IH) are at increased risk of driving accidents. Both excessive daytime sleepiness, i.e. unwanted sleep episodes during the day, and disturbed vigilance are core features of these disorders. We tested on‐the‐road driving performance of patients with narcolepsy or IH coming in for a routine driving fitness evaluation and examined: (1) correlations between driving performance and the Maintenance of Wakefulness Test (MWT), Sustained Attention to Response Task (SART) and Psychomotor Vigilance Test (PVT) as objective tests; (2) the predictive power of the MWT and SART for increased risk of impaired driving; (3) the best set of objective predictors for increased risk of impaired driving. Participants were 44 patients (aged 18–75 years) with narcolepsy type 1 (NT1), type 2 (NT2) or IH. They completed the MWT, SART, PVT, a subjective sleepiness questionnaire, and a standardised on‐the‐road driving test. The standard deviation of the lateral position (SDLP) was used as outcome measure of driving performance. The MWT had low correlation with the SDLP (ρ = −0.41 to −0.49, p < 0.01). The SART and PVT had low correlations with SDLP (ρ = 0.30 and ρ = 0.39, respectively, both p < 0.05). The predictive power of MWT for an increased risk of impaired driving was significant, but low (area under the curve = 0.273, p = 0.012), and non‐significant for SART. We conclude that in our present group, none of the tests had adequate ability to predict impaired driving, questioning their use for clinical driving fitness evaluation in narcolepsy and IH. Real‐time monitoring of sleepiness while driving seems more promising in these patients.

Genetics and Cognitive Vulnerability to Sleep Deprivation in Healthy Subjects: Interaction of ADORA2A, TNF-α and COMT Polymorphisms

Several genetic polymorphisms differentiate between healthy individuals who are more cognitively vulnerable or resistant during total sleep deprivation (TSD). Common metrics of cognitive functioning for classifying vulnerable and resilient individuals include the Psychomotor Vigilance Test (PVT), Go/noGo executive inhibition task, and subjective daytime sleepiness. We evaluated the influence of 14 single-nucleotide polymorphisms (SNPs) on cognitive responses during total sleep deprivation (continuous wakefulness for 38 h) in 47 healthy subjects (age 37.0 ± 1.1 years). SNPs selected after a literature review included SNPs of the adenosine-A2A receptor gene (including the most studied rs5751876), pro-inflammatory cytokines (TNF-α, IL1-β, IL-6), catechol-O-methyl-transferase (COMT), and PER3. Subjects performed a psychomotor vigilance test (PVT) and a Go/noGo-inhibition task, and completed the Karolinska Sleepiness Scale (KSS) every 6 h during TSD. For PVT lapses (reaction time >500 ms), an interaction between SNP and SDT (p < 0.05) was observed for ADORA2A (rs5751862 and rs2236624) and TNF-α (rs1800629). During TSD, carriers of the A allele for ADORA2A (rs5751862) and TNF-α were significantly more impaired for cognitive responses than their respective ancestral G/G genotypes. Carriers of the ancestral G/G genotype of ADORA2A rs5751862 were found to be very similar to the most resilient subjects for PVT lapses and Go/noGo commission errors. Carriers of the ancestral G/G genotype of COMT were close to the most vulnerable subjects. ADORA2A (rs5751862) was significantly associated with COMT (rs4680) (p = 0.001). In conclusion, we show that genetic polymorphisms in ADORA2A (rs5751862), TNF-α (rs1800629), and COMT (rs4680) are involved in creating profiles of high vulnerability or high resilience to sleep deprivation. (NCT03859882).

Trastornos del sueño en emergencias y desastres

Los trastornos del sueño son frecuentes en la población y una causa importante de morbilidad. El objetivo de esta revisión es evaluar las alteraciones del sueño en periodos de emergencia y desastres. A lo largo de la historia, la esfera biopsicosocial y el sueño de las personas ha sido abrumada por múltiples eventos a gran escala, tales como desastres naturales, tragedias provocadas por el hombre, conflictos bélicos, crisis sociales y pandemias, cuya experiencia puede derivar en problemas de salud a corto, mediano y/o largo plazo. En los estudios analizados, se ha observado el impacto negativo de las emergencias y desastres en el sueño, por lo que ha cobrado gran relevancia la difusión y promoción de medidas que incentiven el buen dormir. Debido a la llegada del COVID-19 y a la situación de confinamiento por periodos prolongados en el hogar para prevenir su propagación, han surgido importantes consecuencias a nivel social. Ciertos factores ocupacionales y características de los desastres se asocian a mayor comorbilidad, un alto riesgo de experimentar agotamiento físico, trastornos psicológicos e insomnio en grupos altamente vulnerables, como lo son los profesionales de la salud, rescatistas y socorristas. El insomnio es el trastorno de sueño más frecuente en la población general y su empeoramiento en el contexto de pandemia por COVID-19 representa un nuevo problema en salud pública. Es por ello, que es indispensable promover campañas de prevención de salud física y mental orientados a la pesquisa precoz y manejo de patologías de la esfera psicosocial, dentro de las posibilidades socioeconómicas.

Genetic Markers of Differential Vulnerability to Sleep Loss in Adults

In this review, we discuss reports of genotype-dependent interindividual differences in phenotypic neurobehavioral responses to total sleep deprivation or sleep restriction. We highlight the importance of using the candidate gene approach to further elucidate differential resilience and vulnerability to sleep deprivation in humans, although we acknowledge that other omics techniques and genome-wide association studies can also offer insights into biomarkers of such vulnerability. Specifically, we discuss polymorphisms in adenosinergic genes (ADA and ADORA2A), core circadian clock genes (BHLHE41/DEC2 and PER3), genes related to cognitive development and functioning (BDNF and COMT), dopaminergic genes (DRD2 and DAT), and immune and clearance genes (AQP4, DQB1*0602, and TNFα) as potential genetic indicators of differential vulnerability to deficits induced by sleep loss. Additionally, we review the efficacy of several countermeasures for the neurobehavioral impairments induced by sleep loss, including banking sleep, recovery sleep, caffeine, and naps. The discovery of reliable, novel genetic markers of differential vulnerability to sleep loss has critical implications for future research involving predictors, countermeasures, and treatments in the field of sleep and circadian science.

Self-perceived sleep during the Maintenance of Wakefulness Test: how does it predict accidental risk in patients with sleep disorders?

STUDY OBJECTIVES

To determine whether the feeling of having slept or not during the Maintenance of Wakefulness Test (MWT) is associated with the occurrence of self-reported sleep-related traffic near misses and accidents in patients with sleep disorders.

METHODS

This study was conducted in patients hospitalized in a French sleep center to perform a 4*40 min MWT. Relationship between mean sleep latency on the MWT, feeling of having slept or not during MWT trials and sleep-related near misses and accidents reported during the past year was analyzed.

RESULTS

192 patients suffering from OSAS, idiopathic hypersomnia, narcolepsy, restless leg syndrome or insufficient sleep syndrome were included. 165 patients presented no or one misjudgment of feeling of having slept during MWT trials while 27 presented more than two misjudgments. Almost half of the latter (48.1%) reported a sleepiness-related traffic near miss or accident in the past year versus only one third (27.9%) for the former (P<.05). Multivariate logistic regression showed that patients with more than two misjudgments had a 2.52-fold (95% CI, 1.07-5.95, P<.05) increase in the risk of reporting a sleepiness-related near miss/accident.

CONCLUSIONS

Misjudgment in self-perceived sleep during the MWT is associated with the occurrence of self-reported sleepiness-related traffic near misses and accidents in the past year in patients suffering from sleep disorders. Asking about the perception of the occurrence of sleep during the MWT could be used to improve driving risk assessment in addition to sleep latencies.

Comparison of work-related traffic crashes between male taxi drivers aged ≥65 years and <65 years in South Korea

BACKGROUND

The percentage of drivers aged ≥65 years among all Korean taxi drivers has risen sharply from 3.2% in 2006 to 22.0% in 2016.

OBJECTIVE

This study compared the characteristics of work-related traffic crashes between male taxi drivers aged ≥65 years and <65 years.

METHODS

Using the national compensation data of South Korea, 586 injured male taxi drivers were analyzed based on driver-related (work experience, company size, employment status, injured body part, and injury type) and crash-related factors (time and day of the crash, weather condition, road type, violation and drowsiness) by age group.

RESULTS

For the injured drivers aged ≥65, percentages of the crashes related to some factors were lower than those of the drivers aged <65 years: at night (55.2% vs. 64.0%), on rainy or snowy day (7.8% vs. 21.3%), on straight road (40.5% vs 50.9%) and on the expressway (6.9% vs. 13.0%). However, the percentage of the crashes related to a violation for the injured drivers aged ≥65 years (23.3%) was higher than that of the drivers aged <65 years (13.4%). Furthermore, the taxi drivers aged ≥65 years had a higher death rate (14.7%) than the drivers aged <65 years (8.5%).

CONCLUSIONS

The results can be useful for injury prevention policies and guidelines for elderly taxi drivers such as strengthened qualification tests for the aged drivers and improvement of the working environment.

A systematic review of statistical models and outcomes of predicting fatal and serious injury crashes from driver crash and offense history data

BACKGROUND

Expenditure on driver-related behavioral interventions and road use policy is often justified by their impact on the frequency of fatal and serious injury crashes. Given the rarity of fatal and serious injury crashes, offense history, and crash history of drivers are sometimes used as an alternative measure of the impact of interventions and changes to policy. The primary purpose of this systematic review was to assess the rigor of statistical modeling used to predict fatal and serious crashes from offense history and crash history using a purpose-made quality assessment tool. A secondary purpose was to explore study outcomes.

METHODS

Only studies that used observational data and presented a statistical model of crash prediction from offense history or crash history were included. A quality assessment tool was developed for the systematic evaluation of statistical quality indicators across studies. The search was conducted in June 2019.

RESULTS

One thousand one hundred and five unique records were identified, 252 full texts were screened for inclusion, resulting in 20 studies being included in the review. The results indicate substantial and important limitations in the modeling methods used. Most studies demonstrated poor statistical rigor ranging from low to middle quality. There was a lack of confidence in published findings due to poor variable selection, poor adherence to statistical assumptions relating to multicollinearity, and lack of validation using new data.

CONCLUSIONS

It was concluded that future research should consider machine learning to overcome correlations in the data, use rigorous vetting procedures to identify predictor variables, and validate statistical models using new data to improve utility and generalizability of models.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019137081.

Objective Level of Alertness and Inhibitory Control Predict Highway Driving Impairment in Adults With ADHD

Objective: It remains unclear whether daytime impairments in ADHD patients are better explained by an altered level of alertness and/or by cognitive deficits. The aim of this study was to determine the respective contribution of these factors on driving performance in ADHD adults. Method: ADHD adults (n = 39) and healthy controls (n = 18) underwent a nocturnal polysomnography (PSG) followed by a Maintenance of Wakefulness Test (MWT), a simulated driving task, and a neuropsychological evaluation. Results: ADHD patients had shorter mean sleep latency on the MWT and worse driving performance than controls. They also made more errors on attention and executive functioning tests. Logistic regression analyses showed that inhibition deficits and objective daytime sleepiness predicted highway driving performance in ADHD. Conclusion: Our study shows that not only inhibitory control deficits but also pathological level of alertness independently contribute to highway driving impairment in ADHD patients, providing a better understanding of the pathophysiological mechanisms involved in ADHD.

Shift work and hospital employees: A descriptive multi-site study

BACKGROUND

Hospitals staff with 12-hour and other shift work patterns to account for daily and seasonal workload requirements. Research in healthcare and industries requiring shift work suggests there may be negative health consequences to the workers related to fatigue and other factors. Due to the 24/7 nature of healthcare, it is important to understand the impact of shift work on employees.

OBJECTIVES

The objectives of this study were to investigate how shift work impacts satisfaction with time for social and home activities, based on the Social and Domestic Survey, and chronic fatigue. In addition, an exploration of drowsy driving was undertaken.

DESIGN AND SETTING

This study was a multi-site, descriptive survey study, conducted in 4 acute care hospitals in one metropolitan area in the central United States.

PARTICIPANTS

Participants included healthcare workers in five 24/7 departments: nursing, respiratory therapy, laboratory, radiology and pharmacy.

METHODS

Measures included demographics, work characteristics, and scales including the: Social and Domestic Survey, Circadian Type Inventory, and Chronic Fatigue Scale along with data regarding drowsy driving and automobile accidents/near misses. Data were analyzed using descriptive statistics for sample characteristics. An exploratory factor analysis was conducted on the Social and Domestic Survey. Group differences were tested using Mann-Whitney U tests and regression analyses.

RESULTS

The sample included 1563 subjects (24% RR). The mean age was 40 years. Nursing comprised 77% of the sample, 88% were female, 85% were in a direct patient care role, 67% worked day shift, and 49% worked 12-hour shifts. Pay was important for working night shift, but home life was important for day shift. Night shift (p<0.001) and 12-hour shift workers (p<0.001) had higher chronic fatigue. However, after controlling for other factors, working night shift remained a significant predictor of chronic fatigue and lower satisfaction with time for daily tasks and family/social life, whereas working 12-hour shifts predicted higher satisfaction with daily tasks and periodic life activities. Thirty-five percent of workers reported altering their driving behavior at least half the time due to drowsy driving and 19% had an automobile accident or near miss due to drowsy driving.

CONCLUSIONS

Findings suggest that night and long shifts can have negative effects on fatigue, family, and social life. Drowsy driving and accidents/near misses frequently occur due to drowsy driving. Leaders should continue to study the 24/7 work environment and test measures to improve the safety of shift workers.

Factors associated with serious vehicular accidents: A cross-sectional study in hospital emergency rooms

AIMS

Pictograms on medicine boxes warn of potential drug-related driving hazard; we studied their association with serious accidents.

METHODS

Prospective study in emergency departments of the hospitals in Bordeaux and Périgueux (France), of drivers with serious (admitted at least 24 hours) or nonserious vehicular accidents. Minors, passengers, pedestrians or subjects incapable of answering an interview were excluded. Interviews ascertained driver and accident characteristics, use of drugs with or without pictograms, use of alcohol and abuse substances, sleepiness, distractions, and mind wandering at the time of the accident, RESULTS: Between 18 October 2016 and 26 December 2018, 1200 of the 6212 drivers admitted to the hospital emergency rooms, 741 nonserious, 459 serious, were interviewed. Serious accidents were associated with male sex (odds ratio 1.89, 95% confidence interval [1.36-2.64]), age above 60 years (3.64 [2.21-6.00]), driving on local roads (3.34 [2.34-4.76]), driving a motorcycle (3.39 [2.29-5.00]), having drunk alcohol within 6 hours (2.89 [1.85-4.51]) and using a drug with a pictogram during the 24 hours previous to the accident (1.57 [1.06-2.32]). From 207 police reports, 101 drivers were not responsible, and 106 were responsible, associated with age below 40 years, driving in overcast or rainy weather (2.62 [1.29-5.33]), on local roads (3.89 [1.90-7.95]), and use of at least 1 pictogram drug in the previous week (3.12 [1.31-7.41]).

CONCLUSION

The known risks of alcohol and pictogram drugs, of riding motorcycles and using local roads were confirmed. As measured, behavioural sleepiness did not predict accidents.

Effects of Partial Sleep Deprivation on Braking Response of Drivers in Hazard Scenarios

This study aimed at modeling the Response Time (RT) and Total Braking Time (TBT) of drivers under Partial Sleep Deprivation (PSD). Fifty male participants drove the driving simulator in three experimental conditions: two test sessions and a baseline. The two test sessions were conducted after one and two nights of PSD (sleep = 4.25 ± 0.5 h), respectively. Sleep reduction was recorded using a wrist-worn Actiwatch. The baseline session was conducted after full rest (7-8 h sleep/day for a week). The order of test sessions and baseline was randomized. Each test included two hazard events: 1) pedestrians crossing a road and 2) parked vehicles merging into a roadway. Karolinska Sleepiness Scale (KSS) and Sleepiness Symptoms Questionnaire (SSQ) ratings were also recorded during each drive. Four separate models using parametric accelerated failure time (AFT) with Weibull distribution were developed for RT and TBT in the two events. The models were chosen with clustered heterogeneity to account for intra-group heterogeneity due to repeated measures across tests. In the case of pedestrians crossing event, RT increased by 10% in the first test session and no significant effect observed on RT in the second test session. The overall TBT reduced by 25% and 28% during the first and second PSD sessions, respectively. In the case of vehicle merging event, both response time and total braking time delayed by 44% and 17% respectively after PSD. Other factors such as age, experience, work-rest hours, KSS and SSQ rating, often exercising, approaching speed and braking force were also found significant in the analysis. The parametric AFT approach adopted in this study showed the change in 'response time' and 'total braking time' concerning the type of hazard scenario and partial sleep-deprivation.

Maintenance of wakefulness test: how does it predict accident risk in patients with sleep disorders?

STUDY OBJECTIVE

To determine whether the objective level of alertness measured by the Maintenance of Wakefulness Test (MWT) is associated with the occurrence of self-reported sleepiness-related traffic near misses and accidents related to sleepiness in patients with sleep disorders.

METHODS

This case-control study was conducted over a three-year period in four French sleep centers during a 4∗40 min MWT in patients driving more than 5000 Km/year. Relationship between mean sleep latency on the MWT (MWT latency) and age, sex, driving, sleepiness-related near misses and accidents reported during the previous year, and sleep disorder characteristics was analyzed.

RESULTS

Of 377 patients suffering from OSAS, idiopathic hypersomnia, narcolepsy, restless leg syndrome or insufficient sleep syndrome, 176 were included. 74 cases reported an accident or near miss related to sleepiness at the wheel in the past year, and 102 reported no accident/near miss (control patients). Thirty-one (37.8 %) cases and 9 (8.8 %) controls reported being sleepy at the wheel more than once a week (p < 0.0001). After adjusted regression analyses, patients with MWT latency between 19 and 33 minutes had a 3.2- (CI 95%[1.5; 6.8], p < 0.0001) fold increase in risk of reporting a near miss/ accident and patients with MWT latency <19 min had a 5.5- (CI 95%[2.2; 13.8], p = 0.003) fold increase in this risk, compared to the referent group (MWT latency>33 min).

CONCLUSIONS

MWT latency is associated with self-reported, sleepiness-related near misses and accidents related to sleepiness in the past year in patients routinely investigated in sleep clinics. The MWT could be used to assess driving risk together with clinical interviews assessing sleepiness at the wheel.

Excessive daytime sleepiness and alcohol consumption among commercial drivers

BACKGROUND

Commercial drivers suffering from excessive daytime sleepiness (EDS) have been identified as a major cause of road traffic accidents. Alcohol usage directly affects sleep, adversely affecting next-day alertness and performance.

AIMS

To examine the relationship between alcohol consumption and EDS among commercial truck drivers in Japan and the implications of this on public health.

METHODS

All participants in this cross-sectional study were commercial motor vehicle drivers from Tokyo and Niigata Prefecture. Participants completed a self-administered questionnaire with details of their age, body mass index, alcohol consumption, Epworth Sleepiness Scale (ESS) score and tobacco usage. Participants' oxygen desaturation index was determined by a pulse oximetry device that participants took home.

RESULTS

A total of 1422 males registered with the Japan Trucking Association and aged 20-69 years participated. The multivariate-adjusted odds ratio (OR) of EDS among participants aged <43 years was 0.81 (95% confidence interval (CI) 0.47-1.40) for light drinkers, 0.93 (95% CI 0.51-1.70) for moderate drinkers and 0.61 (95% CI 0.21-1.79) for heavy drinkers, compared to non-drinkers. The multivariate-adjusted OR among participants aged ≥43 years was 1.42 (95% CI 0.59-3.45) for light drinkers, 1.53 (95% CI 0.63-3.75) for moderate drinkers and 3.37 (95% CI 1.14-9.96) for heavy drinkers (P for interaction = 0.05).

CONCLUSION

We found that the association between ESS and alcohol intake was more evident among those aged ≥43 years, who reported higher levels of EDS with increased alcohol consumption.

Fighting fatigue: A conceptual model of driver sleep in the gig economy

The purpose of this paper was to integrate the sleep science, occupational health, and organizational psychology literature to develop a conceptual model of driver sleep and fatigue in the gig economy. We develop an integrative framework, which proposes that aspects of the on-demand driving context influence driver sleep health and fatigue. Driver outcomes include safety incidents, injuries, health, job attitudes, interpersonal behavior, and performance. In addition, moderators, such as driver demographics and health conditions, can interact with aspects of the driver context. A number of practical implications are provided, addressing the ways in which occupational health researchers, online labor platform companies, and drivers can improve sleep health. This is the first paper to provide a broad understanding of how scientists, through both research and practice, can help improve sleep, a primary issue in the ridesharing industry.

Insufficient sleep and fitness to drive in shift workers: A systematic literature review

BACKGROUND

Insufficient sleep, <6.5 h per night, majorly affects shift workers, placing them at higher risk for motor vehicle crash related injury or fatality. While systematic reviews (SLRs) examine the effects of insufficient sleep and driving, to date, no SLR focuses on driver fitness or performance in shift workers.

OBJECTIVES

Determine the class of evidence (Class I-highest to Class IV-lowest), and level of confidence (Level A-high, to Level U-insufficient) in the determinants of driver fitness and performance in shift workers. Next, consider evidence-based recommendations for clinical practice, research, and policy.

METHODS

A protocol was registered on PROSPERO (#CRD42018052905) using an established SLR methodology: a comprehensive electronic database search, study selection, data extraction, critical appraisal, analysis, and interpretation using published guidelines.

RESULTS

Searches identified 1226 unique records with 11(2 on-road, 9 simulator) meeting final inclusion criteria. Class III to IV evidence identified that exposure to overnight shift work possibly predicts (Level C confidence) drivers at risk for adverse on-road outcomes and likely predicts (Level B) drivers at risk for adverse driving simulator outcomes. Higher ratings of subjective sleepiness and extended time driving possibly predict (Level C) drivers at risk for adverse driving simulator outcomes.

CONCLUSIONS

This study demonstrates a low to moderate level of confidence in the determinants of driving in shift workers. A critical need exists for gold-standard on-road assessments integrating complex driving environments representative of real-world demands, targeting tactical and strategic outcomes in a broad spectrum of shift workers.

Does sleep grow on trees? A longitudinal study to investigate potential prevention of insufficient sleep with different types of urban green space

Introduction

To investigate association between urban green space and prevalent and incident cases of insufficient sleep (<6 h sleep per day).

Methods

This longitudinal study examined the odds of prevalent and incident insufficient sleep in relation to indicators of total green space, tree canopy, open grass and other low-lying vegetation in the Sax Institute's 45 and Up Study (baseline 2006–2009; follow-up 2012–2015). Association between green space within 1.6 km road distances and insufficient sleep among 38,982 participants living in Sydney, Wollongong or Newcastle were analysed using multilevel logistic regressions adjusted for confounding.

Results

Participants with more total green space had lower odds of prevalent insufficient sleep (e.g. ≥30% compared with 0-4% total green space odds ratio (OR) = 0.68, 95% credible interval (95%CI) = 0.53, 0.85). The odds of prevalent insufficient sleep were lower among participants with more tree canopy (e.g. ≥30% compared with 0-9% tree canopy OR = 0.78, 95%CI 0.69, 0.88). The odds of incident insufficient sleep were also lower with more tree canopy (e.g. ≥30% compared with 0-9% tree canopy OR = 0.87, 95%CI = 0.75, 0.99). There were no statistically significant associations between prevalent or incident insufficient sleep with open grass or other low-lying vegetation, nor incident sufficient sleep with total green space.

Conclusions

Prioritising restoration and protection of urban tree canopy may help to promote population-wide prevention of insufficient sleep in middle-to-older aged adults.

•

4 cross-sectional studies have previously linked sleep duration with green space.

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This longitudinal study examined prevalence and incidence of short sleep (<6 h).

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We found lower odds of prevalent and incident short sleep with more tree canopy.

Sleep Restriction, Sleep Hygiene, and Driving Safety: The Importance of Situational Sleepiness

Sleep-related accidents are a frequent cause of death and injury in the world. Poor sleep hygiene is responsible for sleep deprivation, which is clearly associated with an increased risk of accidents. Evidence shows that self-reported sleepiness at the wheel and reporting of inappropriate line-crossings are strong predictors of accident risk. Although the Epworth sleepiness scale is widely used in clinical practice, it is not the best to evaluate driving risks. Simple questions on the occurrence of near misses and sleepiness at the wheel should be asked systematically to address the issue of fitness to drive.

Bedtime Procrastination, Sleep-Related Behaviors, and Demographic Factors in an Online Survey on a Polish Sample

The sufficient length and good quality of night sleep play a vital role in maintaining health, well-being and effective functioning. Nevertheless, an increase in the prevalence of sleep deprivation can be observed recently. The concept of bedtime procrastination, defined as going to bed later than intended, has been proposed to explain one of the psychological determinants of sleep deficiency. To investigate the prevalence of bedtime procrastination among Poles we carried out a Polish adaptation of the Bedtime Procrastination Scale (BPS), a self-report questionnaire for measuring the tendency to voluntarily postpone going to bed in the absence of any external circumstances for doing so. The aim of the research was to determine the main psychometric properties of the Polish version of the BPS. We also aimed to identify the relationships between bedtime procrastination and selected demographic variables in the Polish sample, and to examine the impact of bedtime procrastination on self-reported sleep outcomes. The data obtained from online surveys conducted on two Polish samples were analyzed, including demographic factors, self-reported sleep outcomes, and responses to items of the BPS. The Polish version of the BPS has a unifactorial structure like the original version. It also exhibits satisfactory internal consistency and moderate temporal stability in a 10-week retest study. BPS scores were not significantly related to the place of residence, the highest completed level of education, living with a spouse or partner, and living with children. Scores in BPS slightly decreased with age and females scored higher on BPS than males. Higher BPS scores were obtained for a group of students in comparison to a group of subjects who were not students, and lower BPS scores were found in working respondents in comparison to respondents who were not working. BPS scores correlate negatively with sleep length on workdays and a feeling of sleep sufficiency, and positively with sleep length on weekdays relative to workdays, sleeping later than one would like, and a feeling of fatigue. Several relationships between self-reported sleep outcomes and demographic variables were also identified.

Epigenome-wide association analysis of daytime sleepiness in the Multi-Ethnic Study of Atherosclerosis reveals African-American-specific associations

STUDY OBJECTIVES

Daytime sleepiness is a consequence of inadequate sleep, sleep-wake control disorder, or other medical conditions. Population variability in prevalence of daytime sleepiness is likely due to genetic and biological factors as well as social and environmental influences. DNA methylation (DNAm) potentially influences multiple health outcomes. Here, we explored the association between DNAm and daytime sleepiness quantified by the Epworth Sleepiness Scale (ESS).

METHODS

We performed multi-ethnic and ethnic-specific epigenome-wide association studies for DNAm and ESS in the Multi-Ethnic Study of Atherosclerosis (MESA; n = 619) and the Cardiovascular Health Study (n = 483), with cross-study replication and meta-analysis. Genetic variants near ESS-associated DNAm were analyzed for methylation quantitative trait loci and followed with replication of genotype-sleepiness associations in the UK Biobank.

RESULTS

In MESA only, we detected four DNAm-ESS associations: one across all race/ethnic groups; three in African-Americans (AA) only. Two of the MESA AA associations, in genes KCTD5 and RXRA, nominally replicated in CHS (p-value < 0.05). In the AA meta-analysis, we detected 14 DNAm-ESS associations (FDR q-value < 0.05, top association p-value = 4.26 × 10-8). Three DNAm sites mapped to genes (CPLX3, GFAP, and C7orf50) with biological relevance. We also found evidence for associations with DNAm sites in RAI1, a gene associated with sleep and circadian phenotypes. UK Biobank follow-up analyses detected SNPs in RAI1, RXRA, and CPLX3 with nominal sleepiness associations.

CONCLUSIONS

We identified methylation sites in multiple genes possibly implicated in daytime sleepiness. Most significant DNAm-ESS associations were specific to AA. Future work is needed to identify mechanisms driving ancestry-specific methylation effects.

Resetting the late timing of 'night owls' has a positive impact on mental health and performance

BACKGROUND

There is conflict between living according to our endogenous biological rhythms and our external environment, with disruptions resulting in negative consequences to health and performance. This is often documented in shift work and jet lag, but 'societal norms' (eg, typical working hours) can create profound issues for 'night owls', people whose internal biological timing predisposes them to follow an unusually late sleep-wake cycle. Night owls have also been associated with health issues, mood disturbances, poorer performance and increased mortality rates.

METHODS

This study used a randomized control trial design aimed to shift the late timing of night owls to an earlier time (phase advance), using non-pharmacological, practical interventions in a real-world setting. These interventions targeted light exposure (through earlier wake up/sleep times), fixed meals times, caffeine intake and exercise.

RESULTS

Overall, participants demonstrated a significant advance of ∼2 h in sleep/wake timings as measured by actigraphy and circadian phase markers (dim light melatonin onset and peak time of the cortisol awakening response), whilst having no adverse effect on sleep duration. Notably, the phase advance was accompanied by significant improvements to self-reported depression and stress, as well as improved cognitive (reaction time) and physical (grip strength) performance measures during the typical 'suboptimal' morning hours.

CONCLUSIONS

Our findings propose a novel strategy for shifting clock timing towards a pattern that is more aligned to societal demands that could significantly improve elements of performance, mental health and sleep timing in the real world.

Sleeping, sleeping environments, and human errors in South Korean male train drivers

Objectives

Reducing human errors caused by daytime sleepiness among train drivers is important to prevent train accidents. Our purpose of the study was to investigate the association among sleep, workplace sleeping environments, and human errors.

Methods

We recruited 144 South Korean train drivers belongs to the Korean Railroad Corporation. This cross‐sectional data was analyzed to investigate the association of insomnia (insomnia severity index), sleep quality (Pittsburgh sleep quality index), obstructive sleep apnea (Berlin questionnaire), and daytime sleepiness (Epworth scale) with human error and near‐miss experiences. We examined whether human error and near‐miss events were associated with various sleeping environments at work and at home after adjusting for the sleep indices.

Results

The experience of human errors was associated with insomnia and daytime sleepiness, and near‐miss events were associated with insomnia among South Korean drivers. Sleeping environments including cold temperature and odor were related to both human errors and near‐miss events among South Korean train drivers, after adjusted for age, working years, shiftwork, obesity, smoking, binge drinking, regular exercise, caffeine consumption, sleep quality, severity of insomnia, obstructive sleep apnea, and daytime sleepiness.

Conclusions

The train drivers’ workplace sleeping environment is significantly associated with human error events and near‐miss events after adjusting for sleep quality, insomnia, obstructive sleep apnea, and daytime sleepiness. To prevent train accidents caused by human errors, more attention is necessary for improving workplace sleeping environments.

Asleep at the automated wheel-Sleepiness and fatigue during highly automated driving

Due to the lack of active involvement in the driving situation and due to monotonous driving environments drivers with automation may be prone to become fatigued faster than manual drivers (e.g. Schömig et al., 2015). However, little is known about the progression of fatigue during automated driving and its effects on the ability to take back manual control after a take-over request. In this driving simulator study with Nö=ö60 drivers we used a three factorial 2ö×ö2ö×ö12 mixed design to analyze the progression (12ö×ö5ömin; within subjects) of driver fatigue in drivers with automation compared to manual drivers (between subjects). Driver fatigue was induced as either mainly sleep related or mainly task related fatigue (between subjects). Additionally, we investigated the drivers' reactions to a take-over request in a critical driving scenario to gain insights into the ability of fatigued drivers to regain manual control and situation awareness after automated driving. Drivers in the automated driving condition exhibited facial indicators of fatigue after 15 to 35ömin of driving. Manual drivers only showed similar indicators of fatigue if they suffered from a lack of sleep and then only after a longer period of driving (approx. 40ömin). Several drivers in the automated condition closed their eyes for extended periods of time. In the driving with automation condition mean automation deactivation times after a take-over request were slower for a certain percentage (about 30%) of the drivers with a lack of sleep (Mö=ö3.2; SDö=ö2.1ös) compared to the reaction times after a long drive (Mö=ö2.4; SDö=ö0.9ös). Drivers with automation also took longer than manual drivers to first glance at the speed display after a take-over request and were more likely to stay behind a braking lead vehicle instead of overtaking it. Drivers are unable to stay alert during extended periods of automated driving without non-driving related tasks. Fatigued drivers could pose a serious hazard in complex take-over situations where situation awareness is required to prepare for threats. Driver fatigue monitoring or controllable distraction through non-driving tasks could be necessary to ensure alertness and availability during highly automated driving.

Drowsy Driving, Sleep Duration, and Chronotype in Adolescents

OBJECTIVE

To determine whether self-reported drowsy driving was associated with an evening chronotype, a biologically-based difference in circadian sleep-wake timing, and shorter school-night sleep duration in a sample of high school drivers.

STUDY DESIGN

Cross-sectional observational data were obtained from an online survey in spring 2015 of 431 drivers, age 15.5-18.7 years, attending Fairfax County (Virginia) Public schools. Drowsy driving was defined as having ever "driven a car or motor vehicle while feeling drowsy" in the last year. School-night sleep duration was calculated from school-night bedtime and wake time. Those with scores in the lower and upper tertiles of the Morningness-Eveningness Scale for Children were designated as having an evening or morning chronotype, respectively.

RESULTS

Among survey respondents, 63.1% drove at least several times a week and 47.6% reported drowsy driving. The covariate-adjusted prevalence of drowsy driving was 13.9% (95% CI 3.0%-24.9%) higher in students who slept <7 hours on school-nights than in those who slept 8 or more hours. Compared with those with a morning chronotype, the adjusted prevalence of drowsy driving was 15.2% (95% CI 4.5%-25.9%) higher among those with an evening chronotype.

CONCLUSION

Among adolescent drivers, both an evening chronotype and shorter school-night sleep duration were associated with more frequent reports of drowsy driving. Interventions to improve the timing and duration of nighttime sleep in adolescents may reduce the occurrence of drowsy driving.

Insufficient sleep and fitness to drive in shift workers: a systematic literature review protocol

BACKGROUND

The majority of shift workers experience insufficient sleep as a result of their employment. Insufficient sleep is associated with impaired neurocognitive functioning, affecting key skills required for driving, resulting in shift workers experiencing a disproportionate burden of RTC injuries and fatalities. Yet, to our knowledge, no systematic literature review (SLR) exists to critically appraise and synthesise evidence on the determinants of fitness to drive (assessed on-road) and driving performance (assessed in a driving simulator) in shift workers with insufficient sleep.

OBJECTIVES

A SLR protocol is established to conduct analysis and synthesis of the level of evidence and confidence in the determinants of fitness to drive and driving performance, among shift workers with insufficient sleep.

METHODS

This study follows Cooper and Hedges' established SLR methodology: formulate the problem, locate and select studies, collect data, appraise critically, analyse and present data, interpret results and disseminate information. Critical appraisal and analysis follows the 2017 American Academy of Neurology guidelines determining the level of evidence and the level of confidence for each determinant identified in the literature. Protocol and results reporting adhere to the Preferred Reporting Items for Systematic reviews and Meta-Analyses Protocols guidelines.

CONCLUSIONS

This SLR contributes to research evidence examining the impact of insufficient sleep and driver sleepiness on fitness to drive and driving performance. Analysis of the level of evidence and level of confidence in the existing literature will advance evidence-informed prevention strategies and critical decision-making, to mitigate adverse effects of insufficient sleep for improving road safety.

Irregular work schedule and sleep disturbance in occupational drivers-A nationwide cross-sectional study

BACKGROUND

The objective of this study was to investigate the relationship between irregular work schedules and sleep disturbance and compare the impacts of work schedule on sleep disturbance between occupational drivers and office workers.

METHODS

Using data from the 3rd and 4th Korean Working Conditions Survey, 3,070 occupational drivers and 9,898 office workers were included in this study. The subjects' days of night work, evening work, and subjective complaints of sleep disturbance were investigated along with other covariates.

RESULTS

In the multivariate logistic regression analyses, occupational drivers (odds ratio [OR], 95% confidence interval [CI]: 1.51, 1.11-2.05), workers who were engaged in more night work (2.49, 1.84-3.38 for 1-15 days, and 3.80, 2.67-5.41 for 16-30 days) and evening work (2.22, 1.66-2.97 for 1-15 days, and 1.76, 1.26-2.45) were more likely to report sleep disturbance. Moreover, occupational driving showed significant interaction effects with both night and evening work on sleep disturbance, and therefore, showed higher ORs for sleep disturbance in the 16-30 days night (5.38, 3.40-8.52) and evening (3.13, 1.97-4.98) compared to no night and evening working office workers.

CONCLUSIONS

Occupational drivers who are exposed to night work and evening work are at higher risks for sleep disturbance. Therefore, for the public and drivers' safety, optimal work schedules for minimising sleep disturbance should be developed.

Visualization and analysis of mapping knowledge domain of road safety studies

Mapping knowledge domain (MKD) is an important application of visualization technology in Bibliometrics, which has been extensively applied in psychology, medicine, and information science. In this paper we conduct a systematic analysis of the development trend on road safety studies based on the Science Citation Index Expanded (SCIE) and Social Sciences Citation Index (SSCI) articles published between 2000 and 2018 using the MKD software tools VOSviewer and Sci2 Tool. Based on our analysis, we first present the annual numbers of articles, origin countries, main research organizations and groups as well as the source journals on road safety studies. We then report the collaborations among the main research organizations and groups using co-authorship analysis. Furthermore, we adopt the document co-citation analysis, keywords co-occurrence analysis, and burst detection analysis to visually explore the knowledge bases, topic distribution, research fronts and research trends on road safety studies. The proposed approach based on the visualized analysis of MKD can be used to establish a reference information and research basis for the application and development of methods in the domain of road safety studies. In particular, our results show that the knowledge bases (classical documents) of road safety studies in the last two decades have focused on five major areas of "Crash Frequency Data Analysis", "Driver Behavior Questionnaire", "Safety in Numbers for Walkers and Bicyclists", "Road Traffic Injury and Prevention", and "Driving Speed and Road Crashes". Among the research topics, the five dominant clusters are "Causation and Injury Severity Analysis of Road Accidents", "Epidemiologic Study and Prevention of Road Traffic Injury", "Intelligent Transportation System and Active Safety", "Young drivers' driving behavior and psychology", and "Older drivers' psychological and physiological characteristics". Finally, the burst keywords in research trends include Cycling, Intelligent Transportation Systems, and Distraction.

Usefulness of overnight pulse oximeter as the sleep assessment tool to assess the 6-year risk of road traffic collision: evidence from the Taiwan Bus Driver Cohort Study

Background

In order to support health service organizations in arranging a system for prevention of road traffic collisions (RTC), it is important to study the usefulness of sleep assessment tools. A cohort study was used to evaluate the effectiveness of subjective and objective sleep assessment tools to assess for the 6-year risk of both first RTC event only and recurrent RTC events.

Methods

The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1650 professional drivers from a large bus company in Taiwan in 2005. The subjects were interviewed in person, completed the sleep assessment questionnaires and had an overnight pulse oximeter survey. Moreover, this cohort of drivers was linked to the National Traffic Accident Database (NTAD) and researchers found 139 new RTC events from 2005 to 2010. Primary outcomes were traffic collisions from NTAD, nocturnal oxygen desaturation index (ODI) from pulse oximeter, Pittsburg sleeping quality score, Epworth daytime sleepiness score, Snore Outcomes Survey score and working patterns from questionnaires. A Cox proportional hazards model and an extended Cox regression model for repeated events were performed to estimate the hazard ratio for RTC.

Results

The RTC drivers had increased ODI4 levels (5.77 ± 4.72 vs 4.99 ± 6.68 events/h; P  = 0.008) and ODI3 levels (8.68 ± 6.79 vs 7.42 ± 7.94 events/h; P  = 0.007) in comparison with non-RTC drivers. These results were consistent regardless of whether ODI was evaluated as a continuous or a categorical variable. ODI4 and ODI3 levels increased the 6-year RTC risks among professional drivers even after adjusting for age, education, history of cardiovascular disease, caffeine intake, sleeping pills used, bus driving experience and shift modes. Moreover, there was an increased trend for ODI between the stratification of the number of RTCs in comparison with the non-RTC group. In the extended Cox regression models for repeated RTC events with the Anderson and Gill intensity model and Prentice-Williams-Petersen model, measurement of ODI increased hazards of the subsequent RTC events.

Conclusion

This study showed that an increase in the 6-year risk of RTC was associated with objective measurement of ODI for a sign of sleep-disordered breathing (SDB), but was not associated with self-reported sleeping quality or daytime sleepiness. Therefore, the overnight pulse oximeter is an effective sleep assessment tool for assessing the risk of RTC. Further research should be conducted regarding measures to prevent against SDB among professional drivers.

Sleep deficiency and motor vehicle crash risk in the general population: a prospective cohort study

BACKGROUND

Insufficient sleep duration and obstructive sleep apnea, two common causes of sleep deficiency in adults, can result in excessive sleepiness, a well-recognized cause of motor vehicle crashes, although their contribution to crash risk in the general population remains uncertain. The objective of this study was to evaluate the relation of sleep apnea, sleep duration, and excessive sleepiness to crash risk in a community-dwelling population.

METHODS

This was a prospective observational cohort study nested within the Sleep Heart Health Study, a community-based study of the health consequences of sleep apnea. The participants were 1745 men and 1456 women aged 40-89 years. Sleep apnea was measured by home polysomnography and questionnaires were used to assess usual sleep duration and daytime sleepiness. A follow-up questionnaire 2 years after baseline ascertained driving habits and motor vehicle crash history. Logistic regression analysis was used to examine the relation of sleep apnea and sleep duration at baseline to the occurrence of motor vehicle crashes during the year preceding the follow-up visit, adjusting for relevant covariates. The population-attributable fraction of motor vehicle crashes was estimated from the sample proportion of motor vehicle crashes and the adjusted odds ratios for motor vehicle crash within each exposure category.

RESULTS

Among 3201 evaluable participants, 222 (6.9%) reported at least one motor vehicle crash during the prior year. A higher apnea-hypopnea index (p < 0.01), fewer hours of sleep (p = 0.04), and self-reported excessive sleepiness (p < 0.01) were each significantly associated with crash risk. Severe sleep apnea was associated with a 123% increased crash risk, compared to no sleep apnea. Sleeping 6 hours per night was associated with a 33% increased crash risk, compared to sleeping 7 or 8 hours per night. These associations were present even in those who did not report excessive sleepiness. The population-attributable fraction of motor vehicle crashes was 10% due to sleep apnea and 9% due to sleep duration less than 7 hours.

CONCLUSIONS

Sleep deficiency due to either sleep apnea or insufficient sleep duration is strongly associated with motor vehicle crashes in the general population, independent of self-reported excessive sleepiness.

The significance of preexisting medical conditions, alcohol/drug use and suicidal behavior for drivers in fatal motor vehicle crashes: a retrospective autopsy study

Driver fatalities in motor vehicle collisions (MVCs) encompass accidents, suicides, and natural deaths when driving. The objective of this study was to determine the significance of pathology and other autopsy findings for drivers in fatal MVCs. Forensic autopsy records of driver fatalities in southeast Norway between 2000 and 2014 were studied retrospectively. Data from individual police and collision investigation reports were also collected and analyzed. In 406 driver fatalities, the male/female ratio was 340/66; 9% died from natural causes, 9% were suicides, 65% were culpable accidental deaths, 14% were nonculpable deaths, and 3% were undetermined deaths. Head injuries and thoracic injuries were the most common causes of death. A seatbelt had been worn in 50% of the fatalities, and its prevalence did not differ between accidental deaths and suicides. Blood levels of alcohol and/or drugs that indicated impairment at the time of the collision were found in 40% (105/262) of all culpable accidental deaths but in 50% (64/127) of drivers aged up to 35 years. Pathology (most often cardiovascular disease) suggestive of sudden incapacitation before the collision was present in 24% (62/264) of drivers who were culpable in the accident and in 70% (46/66) of culpable drivers older than 55 years. A substantial proportion of drivers are killed in accidental collisions that may have occurred as a result of either alcohol/drug impairment or preexisting disease. Suicides and natural deaths both constitute significant proportions of MVC fatalities and may be misclassified unless a full inquest including an autopsy is performed.

Risk of Motor Vehicle Accidents Related to Sleepiness at the Wheel: A Systematic Review and Meta-Analysis

Study Objectives

Sleepiness at the wheel is widely believed to be a cause of motor vehicle accidents. Nevertheless, a systematic review of studies investigating this relationship has not yet been published. The objective of this study was to quantify the relationship between sleepiness at the wheel and motor vehicle accidents.

Methods

A systematic review was performed using Medline, Scopus, and ISI Web of Science. The outcome measure of interest was motor vehicle accident defined as involving four- or two-wheeled vehicles in road traffic, professional and nonprofessional drivers, with or without objective consequences. The exposure was sleepiness at the wheel defined as self-reported sleepiness at the wheel. Studies were included if they provided adjusted risk estimates of motor vehicle accidents related to sleepiness at the wheel. Risk estimates and 95% confidence intervals (95% CIs) were extracted and pooled as odds ratios (ORs) using a random-effect model. Heterogeneity was quantified using Q statistics and the I2 index. The potential causes of heterogeneity were investigated using meta-regressions.

Results

Ten cross-sectional studies (51,520 participants), six case-control studies (4904 participants), and one cohort study (13,674 participants) were included. Sleepiness at the wheel was associated with an increased risk of motor vehicle accidents (pooled OR 2.51 [95% CI 1.87; 3.39]). A significant heterogeneity was found between the individual risk estimates (Q = 93.21; I2 = 83%).

Conclusions

Sleepiness at the wheel increases the risk of motor vehicle accidents and should be considered when investigating fitness to drive. Further studies are required to explore the nature of this relationship.

Systematic review registration number

PROSPERO 2015 CRD42015024805.

The effects of sleep loss on young drivers' performance: A systematic review

Young drivers (18-24 years) are over-represented in sleep-related crashes (comprising one in five fatal crashes in developed countries) primarily due to decreased sleep opportunity, lower tolerance for sleep loss, and ongoing maturation of brain areas associated with driving-related decision making. Impaired driving performance is the proximal reason for most car crashes. There is still a limited body of evidence examining the effects of sleep loss on young drivers' performance, with discrepancies in the methodologies used, and in the definition of outcomes. This study aimed to identify the direction and magnitude of the effects of sleep loss on young drivers' performance, and to appraise the quality of current evidence via a systematic review. Based on the Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) approach, 16 eligible studies were selected for review, and their findings summarised. Next, critical elements of these studies were identified, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines augmented to rate those elements. Using those criteria, the quality of individual papers was calculated and the overall body of evidence for each driving outcome were assigned a quality ranking (from 'very low' to 'high-quality'). Two metrics, the standard deviation of lateral position and number of line crossings, were commonly reported outcomes (although in an overall 'low-quality' body of evidence), with significant impairments after sleep loss identified in 50% of studies. While speed-related outcomes and crash events (also with very low- quality evidence) both increased under chronic sleep loss, discrepant findings were reported under conditions of acute total sleep deprivation. It is crucial to obtain more reliable data about the effects of sleep loss on young drivers' performance by using higher quality experimental designs, adopting common protocols, and the use of consistent metrics and reporting of findings based on GRADE criteria and the PRISMA statement. Key words: Young drivers, sleep loss, driving performance, PRISMA, the GRADE, systematic review.

Mobile Eye Tracking During Real-World Night Driving: A Selective Review of Findings and Recommendations for Future Research

We exhaustively review the published research on eye movements during real-world night driving, which is an important field of research as fatal road traffic accidents at night out-number fatal accidents during the daytime. Eye tracking provides a unique window into the underlying cognitive processes. The studies were interpreted and evaluated against the back-ground of two descriptions of the driving task: Gibson and Crooks’ description of driving as the visually guided selection of a driving path through the unobstructed field of safe travel; and Endsley’s situation awareness model, highlighting the influence of drivers’ interpreta-tions and mental capacities (e.g., cognitive load, memory capacity, etc.) for successful task performance. Our review unveiled that drivers show expedient looking behavior, directed to the boundaries of the field of safe travel and other road users. Thus, the results indicated that controlled (intended) eye movements supervened, but some results could have also reflected automatic gaze attraction by salient but task-irrelevant distractors. Also, it is not entirely certain whether a wider dispersion of eye fixations during daytime driving (compared to night driving) reflected controlled and beneficial strategies, or whether it was (partly) due to distraction by stimuli unrelated to driving. We concluded by proposing a more fine-grained description of the driving task, in which the contribution of eye movements to three different subtasks is detailed. This model could help filling an existing gap in the reviewed research: Most studies did not relate eye movements to other driving performance measurements for the evaluation of real-world night driving performance.

Traffic crash accidents in Tehran, Iran: Its relation with circadian rhythm of sleepiness

PURPOSE

Road traffic accidents are one of main problems in Iran. Multiple factors cause traffic accidents and the most important one is sleepiness. This factor, however, is given less attention in our country. Road traffic accidents relevant to sleepiness are studied.

METHODS

In this cross-sectional study, all road traffic accidents relevant to sleepiness, which were reported by police, were studied in Tehran province in 2009.

RESULTS

The risk of road traffic accidents due to sleepiness was increased by more than sevenfold (odds ratio = 7.33) in low alertness hours (0:00-6:00) compared to other time of day. The risk of road traffic accidents due to sleepiness was decreased by 0.15-fold (odds ratio = 0.15) in hours with maximum of alertness (18:00-22:00) of circadian rhythm compared to other time of day.

CONCLUSION

The occurrence of road traffic accidents due to sleepiness has significant statistical relations with driving during lowest point of alertness of circadian rhythm.

Leisure-Time Physical Activity and Sedentary Behavior and Their Cross-Sectional Associations with Excessive Daytime Sleepiness in the French SU.VI.MAX-2 Study

BACKGROUND

The potential benefit of physical activity in terms of decreasing excessive daytime sleepiness (EDS) prevalence is unclear, especially in aging adults.

PURPOSE

We aimed to elucidate the associations among physical activity, sedentariness, and EDS in middle-aged and older adults.

METHODS

We conducted a cross-sectional analysis using data from a subsample of participants in the SU.VI.MAX-2 observational study (2007-2009; N = 4179; mean age = 61.9 years). EDS was defined as a score >10 on the Epworth Sleepiness Scale. Leisure-time physical activity and different types of sedentary behavior were assessed with the Modifiable Activity Questionnaire. The associations were examined with multivariable logistic regression models.

RESULTS

In the adjusted multivariable model, total leisure-time physical activity (modeled in quartiles, Q) was significantly, inversely associated with EDS (odds ratios (OR)Q4 vs Q1 = 0.70, 95 % confidence interval (CI) = 0.54-0.89). The association persisted in analyses restricted to individuals not taking sleep medication (ORQ4 vs Q1 = 0.72, 95 % CI = 0.54-0.95). In turn, time spent watching television and time spent reading appeared protective against EDS (ORQ4 vs Q1 = 0.73, 95 % CI = 0.57-0.94; ORQ4 vs Q1 = 0.76, 95 % CI = 0.60-0.97, respectively), whereas time spent on a computer appeared to confer an increased risk for EDS (ORQ4 vs Q1 = 1.30, 95 % CI = 1.05-1.62). When physical activity and sedentariness were modeled jointly, using WHO recommendation-based cutoffs for high/low levels, no significant associations were observed in the fully adjusted models.

CONCLUSIONS

The findings reinforce public health recommendations promoting behavior modification and specifically moderate-intensity exercise in middle-aged and older adults. The association of high physical activity/low sedentariness with EDS, which was not supported by the data, merits further investigation before firm conclusions could be drawn.

Intentions and willingness to drive while drowsy among university students: An application of an extended theory of planned behavior model

A web-based questionnaire was used to assess the utility of constructs from the Theory of Planned Behavior (TPB) and the Prototype Willingness Model (PWM) to predict intentions and willingness to engage in drowsy driving in a sample of 450 university students. Those students who reported more favorable attitudes and subjective norm and greater perceived control and willingness in relation to drowsy driving behavior were more likely to report stronger intentions to engage in drowsy driving behavior. Augmenting the TPB constructs with the PWM construct of willingness significantly explained up to an additional 8 percent of the variance in drowsy driving intention. Perceived behavioral control and willingness were consistently the strongest predictors of drowsy driving intention in the augmented model, which together with the control (personal) variables explained up to 70 percent of the variance in intention. Thus, the Theory of Planned Behavior and the Prototype Willingness Model may be useful for understanding motivational influences on drowsy driving behavior in young people and present promising theoretical frameworks for designing more effective interventions against drowsy driving in this population.

Pharmacological interventions for daytime sleepiness and sleep disorders in Parkinson's disease: Systematic review and meta-analysis

BACKGROUND

Daytime sleepiness and sleep disorders are frequently reported in Parkinson's disease (PD). However, their impact on quality of life has been underestimated and few clinical trials have been performed.

OBJECTIVES

We aimed to assess the efficacy and safety of pharmacological interventions for daytime sleepiness and sleep disorders in PD.

METHODS

Systematic review of randomized controlled trials comparing any pharmacological intervention with no intervention or placebo for the treatment of daytime sleepiness and sleep problems in PD patients.

RESULTS

Ten studies (n = 338 patients) were included. Four trials addressed interventions for excessive daytime sleepiness. Meta-analysis of the three trials evaluating modafinil showed a significant reduction in sleepiness, as assessed by the Epworth Sleepiness Scale (ESS) (- 2.24 points, 95% CI - 3.90 to - 0.57, p < 0.05). In one study, treatment with caffeine was associated with a non-significant improvement of 1.71 points in ESS (95% CI, - 3.57 to 0.13). The six remaining trials assessed interventions for insomnia and REM sleep Behaviour Disorder (RBD). Single study results suggest that doxepin and YXQN granules might be efficacious, while pergolide may be deleterious for insomnia and that rivastigmine may be used to treat RBD in PD patients. However, there is insufficient evidence to support or refute the efficacy of any of these interventions. No relevant side effects were reported.

CONCLUSIONS

Whilst providing recommendations, this systematic review depicts the lack of a body of evidence regarding the treatment of sleep disorders in PD patients; hence, further studies are warranted.