Objective: Despite convincing evidence regarding the risk of highway accidents due to sleepiness at the wheel, highway drivers still drive while sleepy. Sleep disorders can affect driving skills, but the relative impact of sleep complaints among a large population of highway drivers is still unknown.
Methods: Out of 37,648 questionnaires completed by frequent highway users (registered in an electronic payment system), we ran our analyses on 35,004 drivers who responded to all items. The questionnaire previously used in a telephone survey included socio-demographics, driving and sleep disorders items (Basic Nordic Sleep Questionnaire) and the Epworth Sleepiness Scale.
Results: Of all drivers, 16.9% complained of at least one sleep disorder, 5.2% reported obstructive sleep apnea syndrome, 9.3% insomnia, and 0.1% narcolepsy and hypersomnia; 8.9% of drivers reported experiencing at least once each month an episode of sleepiness at the wheel so severe they had to stop driving. One-third of the drivers (31.1%) reported near-miss accidents (50% being sleep-related), 2520 drivers (7.2%) reported a driving accident in the past year, and 146 (5.8%) of these driving accidents were sleep-related. The highest risk of accidents concerned patients suffering from narcolepsy and hypersomnia (odds ratio 3.16, p<.01) or multiple sleep disorders (odds ratio 1.46, p<.001). Other major risk factors were age [18-30 years (OR 1.42, p<.001)] and being unmarried (OR 1.21-fold, p<.01).
Conclusions: In regular highway drivers, sleepiness at the wheel or sleep disorders such as hypersomnia and narcolepsy are responsible for traffic accidents independent of age, sex, marital status or socio-professional categories.
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