Sleep disorders: A potential role in New Zealand motor vehicle accidents

Background: The potential role of sleep disorders in New Zealand motor vehicle accidents (MVA) has not been systematically studied. Aims: To trial a recruitment method and document the frequency of sleep disorders in drivers attending an emergency department with injury following MVA. Methods: Injured drivers admitted to Wellington Hospital Emergency Department were prospectively recruited by letter and follow-up telephone call. Data from a traffic accident, health and sleep questionnaire and polysomnography were collected and analysed using the SPSS statistical package. Results: Of 120 eligible drivers, 40 (33%) completed the study protocol. The mean age of participants was 44 ± 17 years. Non-participants were younger (mean age 33 ± 14 years, P < 0.01) and more often of Asian or Pacific Island ethnicity (P < 0.01). Twenty-seven (67%) felt unrefreshed on waking and 10 (25%) had an elevated Epworth Sleepiness Score (> 10/24). Six (15%) felt drowsy or fell asleep prior to the accident. Sleep disorders were common (40%): obstructive sleep apnoea 14 (35.9%), periodic limb movements of sleep three (7.7%), sleep restriction (< 6 h sleep on a regular basis) five (12.5%), and insomnia one (2.5%). Conclusions: Daytime somnolence and sleep disorders were commonly found in drivers attending the Emergency Department after accidents resulting in injury. Driver fatigue and sleep disorders should be considered as a potential contributing factor in New Zealand MVAs. Recruitment of drivers following a MVA via the Emergency Department is challenging. Strategies to improve recruitment are discussed.