Study objectives: To assess the association between insomnia symptoms and risk of fatal unintentional injuries.
Design: Population-based prospective cohort study with a mean follow-up of 14 y, linking health survey data with information on insomnia symptoms to the National Cause of Death Registry.
Setting: Nord-Trøndelag County, Norway.
Participants: A total of 54,399 men and women 20-89 y of age who participated in the Nord-Trøndelag Health Study between 1995 and 1997.
Interventions: N/A.
Measurements and results: There were 277 unintentional fatal injuries, including 57 fatal motor vehicle injuries during follow-up. There was a dose-dependent association between the number of insomnia symptoms and risk of unintentional fatal injuries (P for trend 0.001) and fatal motor vehicle injuries (P for trend 0.023), respectively. The proportion of unintentional fatal injuries cases that could have been prevented in the absence of difficulties initiating sleep, difficulties maintaining sleep, and having a feeling of nonrestorative sleep were 8%, 9%, and 8%, respectively. The corresponding estimates for motor vehicle injuries were 34%, 11%, and 10%.
Conclusion: Insomnia is a major contributor to both unintentional fatal injuries in general as well as fatal motor vehicle injuries. Increasing public health awareness about insomnia and identifying persons with insomnia may be important in preventing unintentional fatal injuries.
Keywords: accidents; injuries; insomnia symptoms; motor vehicle injuries; sleep; unintentional fatal injuries.