These accidents also claimed the lives of more than one in 10 injured service members deployed to those conflicts, the study found.
"Nonbattle injury among deployed forces may have different possible causes, deplete medical resources, increase costs, decrease mission capabilities, and result in long-term disability for injured service members," wrote the research authors, led by Dr. Tuan D. Le
of the US Army Institute of Surgical Research at Fort Sam Houston in San Antonio.
Injuries unrelated to combat accounted for 13% of hospital admissions during the Vietnam War and 25% during both Operation Desert Shield and Operation Desert Storm, Le and his co-authors noted. And half of all US service member deaths during Operation Desert Shield were caused by nonbattle injuries.
Understanding the possible causes of injuries in Afghanistan and Iraq could help create better safety policies in the military, they said.
Le and his co-authors mined the Department of Defense Trauma Registry for data concerning 29,958 service members injured in three military operations conducted in Iraq and Afghanistan from January 1, 2003, through December 31, 2014.
Nonbattle injuries accounted for 34.1% of all injuries and 11.5% of all deaths among service members admitted to a military medical facility during the study period, the researchers found.
Rates of injuries unrelated to combat were higher among women than among men: about 63%, vs. 33%. A higher proportion of nonbattle injuries occurred among members of the Air Force (66.3%) and Navy (48.3%) than in members of the Army (34.7%) and Marine Corps (25.7%).
Injuries unrelated to combat included falls (21.3%), motor vehicle crashes (18.8%), machinery or equipment accidents (12.6%), blunt objects (10.8%), gunshot wounds (7.1%) and sports (6.8%). Blunt trauma was the diagnosis for more than two-thirds of all injured service members.
Dr. Todd E. Rasmussen, an associate dean of research at the Uniformed Services University of the Health Sciences in Bethesda, Maryland, wrote in a commentary
that the new study is "a wake-up call.'
Rasmussen, who was not involved in the research, added that the three leading causes of nonbattle injuries -- falls, motor vehicle accidents, and machinery or equipment incidents -- are mostly preventable.
"Not to be overlooked are successes identified in this analysis, such as the relatively low rate of unintentional firearm injury," he said. "The fact that only 728 service members sustained an inadvertent firearm injury during a 12-year period in which hundreds of thousands of troops were deployed with a great assortment of weaponry is notable."
He believes that the low rate of this type of injury "points to the professionalism of military members as it relates to possessing firearms as well as the success of training and safety initiatives."
"Armed with this information," Rasmussen wrote, the military should make new or increased efforts to reduce accidental injuries among service members.
Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York, said the study supports research showing that accidents, in particular falls and motor vehicle crashes, continue to be a leading cause of injuries unrelated to combat.
"While both world wars and Korea dealt with infectious diseases as the main reasons for nonbattle injuries, [accidental wounds] became the overriding concern starting with the Vietnam War," said Glatter, who was not involved in the new research.
The study's main weakness is that it looks at data collected in the past, so poor reporting of information may lead to inaccuracies, he said. Overall, though, the message is clear.
"What we're seeing in civilian life is exactly what's happening to people in the military. They have the same issues we have," he said. "The military needs to focus on keeping troops healthy while avoiding injury -- a task easier said than done."
In particular, the young and athletic service members should avoid distraction with smartphones and other electronic devices while performing noncombat tasks, Glatter said: "Getting proper amounts of sleep and staying well-hydrated can also help to reduce the risk of noncombat injury."
Le and his co-authors agree that military safety needs attention: "We propose that for future conflicts, rates of nonbattle injuries should be closely monitored and targeted safety interventions should be rapidly deployed."