The present investigation was based on the files of the Boards of Traffic Accident Investigation of insurance companies with regard to those fatal motor-car accidents in Finland during the period 1972-1979, where the driver or front seat passenger had died. The analysis concerned a total of 1197 fatalities. In collisions where the other vehicle had been clearly heavier (mass distribution smaller than 1/5) head injuries were significantly (p less than 0.001) more often found as the main cause of death (57.3%) than was the case when colliding vehicles had approximately the same weight (mass distribution 2/3-3/2), in which case head injuries were found in 37.8% of the cases to be the main cause of death. When the speed was over 80 kph , the number of head injuries as the main cause of death increased significantly (p less than 0.001) in collisions where the vehicles had approximately the same weight (mass distribution 2/3-3/2) and in single accidents of motor-cars. The wearing of seat belts had an effect on the distribution of causes of death in single accidents of motor-cars and in collisions where the vehicles had approximately the same weight but did not effect the distribution of causes of death in collisions where the other vehicle was clearly heavier. In single accidents of motor-cars where the victims had not used seat belts, there were more head injuries (54.2%) as the main cause of death than in victims who had used seat belts (head injuries in 36.8% as the main cause of death). In collisions where the vehicles had approximately the same weight, cervical spine injuries were more common causes of death in victims who had used seat belts than in those who had not (21.3%/13.7%). The mechanism of fatal cervical spine injuries in victims who had used seat belts was the rapid bending of the neck due to maximal deceleration in 38% of cases.
Fatal and nonfatal head and face injuries to unhelmeted bicyclists were analyzed to assess the injury-reducing potential of bicycle helmet use. Of the fatally injured, 64% (median age, 55 years) had fatal head and face injuries compared with 38% (median age, 18 years) with head and face injuries in the nonfatal injury group. The fatally injured often had multiple impact points, mostly to the occipital and temporal regions. Brain contusions, most often to the frontal and temporal lobes, were the most common cause of fatal injury, followed by subdural hematomas. In the nonfatal injury group abrasions/lacerations were most common type of injury, followed by cerebral concussions/contusions and superficial contusions. If all types of injuries to bicyclists are taken into account a helmet might have had an injury-reducing effect in two of every five fatal cases and in one of every five nonfatal cases. To increase the helmet use among bicyclists, a law, as in Australia, would be an excellent instrument.
The effectiveness of helmets at preventing cycling fatalities, a leading cause of death among young adults worldwide, is controversial, and safety regulations for cycling vary by jurisdiction. We sought to determine whether nonuse of helmets is associated with an increased risk of fatal head injury.
We used a case-control design involving 129 fatalities using data from a coroner's review of cycling deaths in Ontario, Canada, between 2006 and 2010. We defined cases as cyclists who died as a result of head injuries; we defined controls as cyclists who died as a result of other injuries. The exposure variable was nonuse of a bicycle helmet.
Not wearing a helmet while cycling was associated with an increased risk of dying as a result of sustaining a head injury (adjusted odds ratio [OR] 3.1, 95% confidence interval [CI] 1.3-7.3). We saw the same relationship when we excluded people younger than 18 years from the analysis (adjusted OR 3.5, 95% CI 1.4-8.5) and when we used a more stringent case definition (i.e., only a head injury with no other substantial injuries; adjusted OR 3.6, 95% CI 1.2-10.2).
Not wearing a helmet while cycling is associated with an increased risk of sustaining a fatal head injury. Policy changes and educational programs that increase the use of helmets while cycling may prevent deaths.