Auto Accident Risks Significantly Increase Following Concussion Injury: Study

Researchers warn that the risk of an automobile accident is the greatest during the first month after a concussion or traumatic head injury.

New research suggests that individuals who suffer a concussion may face an elevated risk of being involved in a serious auto accident for up to ten years after their injury, with the greatest risk during the first few weeks after experiencing the head injury.

In a study published in the journal BMJ Open on November 5, researchers examined whether individuals who experience a concussion face a higher risk of serious accidents in the years that follow, both as drivers and as pedestrians.

A concussion is a mild form of traumatic brain injury that occurs when a sudden impact or jolt causes the brain to move or shake inside the skull. Like other traumatic brain injuries (TBIs), concussions have been linked to an increased risk of behavioral issues in children, strokes, and even the development of certain brain tumors later in life. 

They can also impair driving ability, as lingering symptoms such as dizziness, insomnia, depression, brain fog, and delayed reaction times may persist for weeks or longer after the initial injury.

In the new study, researchers from the Sunnybrook Research Institute in Ontario, Canada, found that the risk of serious auto accidents was especially high during the first month after a concussion, affecting individuals both behind the wheel and on foot.

Led by Donald A. Redelmeier, the researchers looked at more than 3 million patients who had experienced either a concussion or an ankle sprain. Of those participants, 425,158 had suffered a concussion, while 2,611,870 were treated for an ankle sprain.

In the decade following diagnosis, approximately 1 out of 15 of the study’s participants were injured in an auto accident, with those who had suffered a concussion being 49% more likely to be injured than those who had an ankle sprain.

In particular, patients with a concussion accounted for 33,508 car crashes over 3,166,718 patient years, which equals a risk of 10.58 per 1,000 years annually. On the other hand, patients with an ankle sprain suffered 167,095 crashes per 27,022,446 patient years, equating to 6.18 per 1,000 years.

For those suffering from a concussion, the increased risk of accidents was particularly high in the first month following diagnosis, with more than 5,000 crashes occurring during that period, equating to a sixfold increase.

Ultimately, the increased crash risk for concussion patients who were both driving and walking accounted for:

• 1,633 ambulance calls
• 59,978 hospital days
• $835 million in medical expenses

“The increased risk of a motor vehicle crash was especially evident for the first month after a concussion, distinct from other risk factors such as ADHD, unrelated to the risks of other medical emergencies and increased further after a second concussion.”

— Donald A. Redelmeier, Concussions and risk of a subsequent traffic crash: retrospective cohort analysis in Ontario, Canada

Researchers advised patients to address symptoms like insomnia, headaches, depression or substance misuse, and avoid driving at high speeds, late at night or in bad weather during the first month after a concussion. Redelmeier’s team also recommended that doctors provide guidance to patients on road safety during their most vulnerable period.

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