October 6, 2010 - Injury Free Coalition for Kids of Baltimore
Accidents involving four-wheelers caused serious injuries and death significantly more often than those involving dirt bikes, Cassandra Villegas, MPH, of Johns Hopkins, and colleagues found.
Their analysis of the National Trauma Data Bank was presented at the American College of Surgeons meeting here. "All-terrain vehicles have been increasing in popularity, and we also know that their injuries have been increasing across the U.S.," Villegas said in an interview.
But even so, Villegas said she and her colleagues were surprised by the findings.
Four wheels are perceived to be a safer, more stable platform for off-road motor transportation and sports, the group explained.
However, that's not what they found among the 13,749 off-road motorcycle and 44,509 all-terrain four-wheeled vehicle crash trauma patients of all ages in the database.
Unadjusted mortality was more than twice as high for four-wheeler accidents at 2.6% compared with motorbikes' 1.2% (P<0.05).
The odds of mortality remained 1.51-fold higher (95% confidence interval 1.03 to 2.20) with all-terrain vehicles (ATVs) after adjustment for gender, age, race, geographic region, insurance status, injury severity score, severe head or extremity injury, Glasgow Coma Scale motor score, presence of shock on admission, and helmet use.
With ATVs, the likelihood of ending up in the intensive care unit was 55% higher (adjusted odds ratio 1.55, 95% CI 1.42 to 1.70), while the adjusted chance of an injury that required being put on a ventilator was 1.42-fold higher (95% CI 1.17 to 1.72) compared with off-road motorcycles.
Mean injury severity scores were largely similar, although the difference favored off-road motorbikes significantly (10.5 versus 10.9, P<0.05).
The reason for these differences wasn't clear from the database, Villegas noted.
"Some of the things we'd really like to know, whether there were crush injuries or not, just isn't inside that database," she told MedPage Today.
"But what we do know," she added, "is that those patients suffer severe thoracic and abdominal injuries and higher severe head injuries, which all point to the idea that they may be suffering from higher crush injuries, which may be specific to ATVs."
Not only are the four-wheeled vehicles heavier, but current off-road motorcycle helmet and safety laws do not apply to ATVs, the researchers noted.
The group urged efforts to inform riders of the risks involved as well as to increase the use of helmets and protective gear through education and regulation. Perhaps some of the same safety lessons learned in the automobile industry could be applied off-road, such as airbags or rollbars to prevent crush injuries, Villegas suggested.
"We want to raise awareness that ATVs are quite serious vehicles," Villegas said in the interview. "Almost anyone can jump on one and ride one but sometimes the risk of injuries, especially serious injuries, is underappreciated."
Cassandra Villegas, MPH
Bloomberg School of Public Health
Johns Hopkins University