Virginie Bayon

Societal costs of insomnia.

Insomnia is the most common sleeping disorder and has been recognized as a major public health issue, associated with a high societal cost. The aim of this review is firstly to understand how the socio-demographic and career characteristics of insomniacs may influence the economical consequences of this disease. Secondly, it also tries to explain how patients seek help to cope with their insomnia. The review aims to carefully describe the possible links between insomnia and public health concerns as to point out what are the certitudes and the missing data on the consequences of insomnia on work, economics, accidents, costs and health related quality of life (HrQol).

Impact of sleep apnea on economics

Obstructive sleep apnea syndrome (OSA) alters sleep quality and is associated with sleepiness and decreased cognitive functioning. It has therefore always been recognized as a major public health issue with potential societal consequences: accidents, increased morbidity, and cognitive deficits impairing work efficiency. The number of patients diagnosed and treated for OSA has increased drastically in the last few years. In response to this epidemic, health authorities have encouraged studies investigating how patients cope with OSA and also its diagnosis, comparing ambulatory to hospital-based polysomnography. Based on epidemiological knowledge, this review aims to carefully describe the possible links between sleep apnea and public health concerns along with identifying the certitudes and missing data concerning the consequences of sleep apnea on accidents, work, economics and health-related quality of life.

Maintenance of Wakefulness test, obstructive sleep apnea syndrome, and driving risk

Sleepiness at the wheel is a major risk factor for traffic accidents. Because of the potential medical and legal implications, in this study, we evaluated the correlation between subjective and objective measures of sleepiness and driving performances in patients suffering from excessive daytime sleepiness.

Extended Driving Impairs Nocturnal Driving Performances

Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3–5am, 1–5am and 9pm–5am) on open highway. Fourteen young healthy men (mean age [±SD] = 23.4 [±1.7] years) participated Inappropriate line crossings (ILC) in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3–5am) driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05) for the intermediate (1–5am) driving session and by 4.0 (CI, 1.7 to 9.4; P<.001) for the long (9pm–5am) driving session. Compared to the reference session (9–10pm), the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001), 15.4 (CI, 4.6 to 51.5; P<.001) and 24.3 (CI, 7.4 to 79.5; P<.001), respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05) and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01). At night, extended driving impairs driving performances and therefore should be limited.

Sleepiness, near-misses and driving accidents among a representative population of French drivers

Study objectives were to determine the prevalence of sleepy driving accidents and to explore the factors associated with near‐miss driving accidents and actual driving accidents in France. An epidemiological survey based on telephone interviews was conducted on a representative sample of French drivers. The questionnaire included sociodemographics, driving and sleep disorder items, and the Epworth sleepiness scale. Of 4774 drivers (response rate: 86%), 28% experienced at least one episode of severe sleepiness at the wheel (i.e. requiring to stop driving) in the previous year; 11% of drivers reported at least one near‐miss accident in the previous year (46% sleep‐related); 5.8% of drivers reported at least one accident, 5.2% of these being sleep related (an estimate of 90 000 sleep‐related accidents per year in France). Sleepy driving accidents occurred more often in the city (53.8%), during short trips (84.6%) and during the day (84.6%). Using logistic regression, the best predictive factor for near‐misses was the occurrence of at least one episode of severe sleepiness at the wheel in the past year [odds ratio (OR) 6.50, 95% confidence interval (CI), 5.20–8.12, P < 0.001]. The best predictive factors for accidents were being young (18–30 years; OR 2.13, 95% CI, 1.51–3.00, P < 0.001) and experiencing at least one episode of severe sleepiness at the wheel (OR 2.03, 95% CI, 1.57–2.64, P < 0.001). Sleepiness at the wheel is a risk factor as important as age for traffic accidents. Near‐misses are highly correlated to sleepiness at the wheel and should be considered as strong warning signals for future accidents.

Insomnia and accidents: cross-sectional study (EQUINOX) on sleep-related home, work and car accidents in 5293 subjects with insomnia from 10 countries.

The link between sleepiness and the risk of motor vehicle accidents is well known, but little is understood regarding the risk of home, work and car accidents of subjects with insomnia. An international cross‐sectional survey was conducted across 10 countries in a population of subjects with sleep disturbances. Primary care physicians administered a questionnaire that included assessment of sociodemographic characteristics, sleep disturbance and accidents (motor vehicle, work and home) related to sleep problems to each subject. Insomnia was defined using the International Classification of Sleep Disorders (ICSD‐10) criteria. A total of 5293 subjects were included in the study, of whom 20.9% reported having had at least one home accident within the past 12 months, 10.1% at least one work accident, 9% reported having fallen asleep while driving at least once and 4.1% reported having had at least one car accident related to their sleepiness. All types of accident were reported more commonly by subjects living in urban compared to other residential areas. Car accidents were reported more commonly by employed subjects, whereas home injuries were reported more frequently by the unemployed. Car accidents were reported more frequently by males than by females, whereas home accidents were reported more commonly by females. Patients with insomnia have high rates of home accidents, car accidents and work accidents related to sleep disturbances independently of any adverse effects of hypnotic treatments. Reduced total sleep time may be one factor explaining the high risk of accidents in individuals who complain of insomnia.

Sleep debt and obesity

Abstract Short sleep duration has been shown to be associated with elevated body mass index (BMI) in many epidemiological studies. Several pathways could link sleep deprivation to weight gain and obesity, including increased food intake, decreased energy expenditure, and changes in levels of appetite-regulating hormones, such as leptin and ghrelin. A relatively new factor that is contributing to sleep deprivation is the use of multimedia (e.g. television viewing, computer, and internet), which may aggravate sedentary behavior and increase caloric intake. In addition, shift-work, long working hours, and increased time commuting to and from work have also been hypothesized to favor weight gain and obesity-related metabolic disorders, because of their strong link to shorter sleep times. This article reviews the epidemiological, biological, and behavioral evidence linking sleep debt and obesity.

Neuroendocrine, immune and oxidative stress in shift workers

Shift work is commonly associated with disturbed life rhythms, resulting in chronic exposure to circadian desynchronization and sleep restriction. Epidemiological data have shown that shift workers are at an increased risk of cardiovascular disease and breast cancer. In this review, we will explore how observed increases in neuroendocrine stress, non-specific immune responses and pro-oxidative status could act as biological mediators for these damaging health risks in shift workers. To explain these risks, compelling evidence from laboratory studies links circadian misalignment but also sleep restriction to disruptions in the neuroendocrine, immune and oxidative stress systems. Assessment of neuroendocrine, oxidative and immune stress in the shift worker population is still a limited and novel field, which may have considerable clinical relevance. Finally, we will consider the potential benefits of a countermeasure, such as napping, in minimizing the neuroendocrine and immune stress and cardiovascular risk imposed by shift work.

The role of actigraphy in the assessment of primary insomnia: a retrospective study

OBJECTIVE The aim of our study was to evaluate quantitative actigraphic criteria obtained using the Actiwatch device (AW64; Cambridge Neurotechnology Ltd., Cambridge, UK) to differentiate participants with insomnia from normal sleepers. METHODS In our retrospective study, we recovered 493 actigraphic records from two sleep measure databases of patients with insomnia (n=151) and one of normal sleepers (n=342). We considered the following actigraphic sleep parameters: time in bed (TIB), sleep-onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), number of awakenings (NWAK), terminal wakefulness (TWAK), fragmentation index (FI), and mean motor activity (MA). We also considered two actigraphic circadian indexes: interdaily stability and intradaily variability. Using the Youden index, we calculated the quantitative actigraphic criteria that performed best for each actigraphic sleep parameter. Finally, we created receiver operating characteristic curves to test the accuracy of each criterion identified. RESULTS All sleep parameters except TST and TWAK differentiated the two groups of participants, allowing calculation of quantitative actigraphic criteria. There were no differences in the circadian indices. CONCLUSIONS The quantitative actigraphic criteria obtained in our study were not the same as those obtained previously with a different device, suggesting the need to adopt shared technical solutions for actigraphy.

Socio-professional handicap and accidental risk in patients with hypersomnias of central origin

Narcolepsy and idiopathic hypersomnia profoundly affect quality of life, education and work. Young patients are very handicapped by unexpected sleep episodes during lessons. Professionals frequently complain about sleepiness at work. Motor discomfort (i.e., cataplectic attacks) surprisingly is less handicapping in narcoleptics than sleepiness but only a few studies clearly assess the problem. Quality of life is also largely impaired in its physical and emotional dimensions. Sleepiness is the major factor explaining a decrease of quality of life and unexpectedly cataplectic attacks have little impact on patients. Another potential problem for these patients is the risk of accidents at work or when driving. Narcoleptic and hypersomniac patients have a higher risk of accidents than apneic or insomniac subjects. But, confounding factors such as duration of driving, number of cataplectic attacks or even objective level of alertness are not always entered in the analytic models mainly because of small samples of patients. Unlike in apneic patients, the effect of treatment on accidental risk has not been studied in narcoleptics or in hypersomniacs. Epidemiological data are needed to improve knowledge concerning these areas. Clinical trials assessing the impact of treatment on driving and work are also urgently needed. Finally, medical treatment does not seem to be completely efficient and physicians should pay more attention to the education, work, life and social environment of their patients.