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Sleep Disorders & Accidents
  • An Introduction to Sleep
  • Sleep Disorders
  • Driver Sleepiness
  • Sleep Disorders and Accidents





      Whilst Sleep Deprivation due to excessive driving hours is probably the single most important cause of driver sleepiness, sleep disorders are thought to account for a significant number of sleep-related accidents due to excessive daytime sleepiness.

    Sleep Disorders account for a significant burden to the economy and disrupt the daily lives of millions of people worldwide. In the USA, more than 30 million people were referred to sleep disorder centres last year. In the United Kingdom, the prevalence of sleep disorders and medically related sleep disorders is increasing.

    The Common Causes of Excessive Daytime Sleepiness (EDS)
  • Insufficient Sleep Quantity or Sleep Deprivation
  • Insufficient Sleep Quality: Obstructive Sleep Apnoea, PLMS
  • Neurological Disorders: Narcolepsy; Idiopathic Hypersomnia; Head Injury
  • Disorders of our Sleep-Wake Cycle e.g. Shift Work Sleep Disorder
  • Drug and Alcohol use

    Insufficient Sleep Quantity (Insomnia) and Sleep Deprivation
    The inability to initiate and/or maintain sleep at the appropriate (nocturnal) time is highly prevalent in all populations. The accepted prevalence of Insomnia is between 5-12% of the general population and significantly higher for the medical and psychiatrically ill. Conservative estimates of prevalence estimate that about 5 million people suffer from short-term insomnia and approximately 2-3 million people in the UK have chronic sleep initiation and/or maintenance disorders. Excessive working hours, Economic demands and ambitions all lead to a problem of chronic sleep deprivation, subsequent sleepiness and a higher proven risk of fatal road accidents.

    Insufficient Sleep Quality – Obstructive Sleep Apnoea (OSA)

    A condition of interruptions or pauses in breathing whilst asleep – signs of this disorder include obesity, snoring, sleep interrupted by intermittent gasping for breath, and excessive daytime sleepiness.  

    Obstructive Sleep Apnoea (OSA) and other sleep related breathing disorders constitute a significant health and economic burden. OSA is commoner in men and has a prevalence of about 4% in men below 40years of age. The prevalence increases with age and about 8% of men above 50 years have a clinically diagnosable OSA syndrome. OSA is usually treated with Continuous Positive Airway Pressure (CPAP). The relationship between OSA and cardiac disease is only now emerging as significant. Recent international peer reviewed publications cite a possible causative role of OSA in the genesis of Essential Hypertension, Diabetes Mellitus and Ischaemic Heart Disease and Stroke.

    How common is OSA in Commercial Drivers
    Allan Pack and his colleagues at the University of Pennsylvania, USA, recently published the first comprehensive epidemiological study on the prevalence of OSA in commercial drivers. They found that 28% of Commercial Drivers have OSA i.e. 7 times more than the normal population. They calculated from these results that a comprehensive screening and treatment programme can prevent up to 60% of HGV related accidents. They have strongly recommended the implementation of sleepiness and OSA screening as an essential part of driver employment health evaluation;

    What is the Risk of people with OSA in causing road accidents?
    Drivers with OSA have been thoroughly researched as a group with regard to their risk of increased motor vehicle collisions (MVC). As a group, untreated patients with OSA have a 6 – 13 fold increased risk of causing a fatal road accident when compared to the normal population (Teran-Santos, NEJM 1999; 340: 847; Masa A J. Resp Crit Care Med 2000; 162: 1407) These studies have involved large groups of patients and are internationally recognised to reflect the degree of risk of fatal accidents by patients with OSA.

    The Evidence for Removal of Risk with Treatment
    Charles FP George and his team at The University of Western Ontario, Canada, published a seminal article in the world renowned journal Thorax in 2001. They have shown quite clearly a Reduction in Motor Vehicle Collisions following treatment of OSA. They studied 210 patients with OSA who were treated for at least 3 years. MVC rates were compared for 3 years before and after therapy for patients and for a control group. Untreated patients with OSA had more MVCs than controls and following treatment the number of MVCs/driver/year fell to same level as the control group i.e. normalised. They concluded that ‘’the risk of MVCs due to OSA is removed when patients are treated. As such, any restrictions on driving because of OSA could be safely removed after treatment’’.

    Cost benefits of a Screening Programme and Treating Sleep Disorders
    Alex Sassani and colleagues from the University of California have for the first time calculated the cost of fatalities and the cost benefit of treating sleep apnoea. Writing in the May 2004 edition of the international journal SLEEP, they conclude that: ‘’More than 800,000 drivers were involved in OSA-related motor-vehicle collisions in the USA in the year 2000.These collisions cost $15.9 billion and 3,400 lives in the year 2000. In the United States, treating all drivers suffering from OSA would cost $3.18 billion, saving $11.1 billion in collision costs, and 2000 lives annually. Annually, a significant portion of motor-vehicle collisions, costs, and deaths are related to OSA. With appropriate treatment, most of these collisions, costs, and deaths can be prevented. Treatment of OSA benefits both the patient and the public’’.