(Reuters Health) - Falls, car crashes and other accidents off the battlefield cause one-third of injuries and about one in 10 deaths among U.S. service members deployed to Iraq and Afghanistan, a U.S. study suggests.

Researchers examined data on almost 30,000 casualties from 2003 to 2014 in the Department of Defense Trauma Registry, including cases that happened both on and off the battlefield. Overall, roughly half of these injuries were caused by explosives, and another 15 percent were from gunshot wounds.

But overall, about 34 percent of injuries were not sustained in battle. Injuries off the battlefield often involved motor vehicle crashes; other incidents involved operating machinery or playing sports, the study also found.

“It was clear from my own experience as a physician deployed to Afghanistan in 2011 that the deployed environment presents a significant risk of injury due to accidents and mishaps,” said senior study author Dr. Kevin Akers, a lieutenant colonel at the U.S. Army Institute of Surgical Research at Fort Sam Houston in Texas.

“There is a lot of heavy machinery which may be operating day and night, in all weather conditions, and during periods of intense stress and distraction,” Akers said by email. “Even so, I was surprised by the proportion of casualties in the DOD Trauma Registry attributed to non-battle injury, which seemed higher than what I would have expected.”

Non-battle injuries were most common in the Air Force, accounting for 67 percent of cases, followed by the Navy at 48 percent, the Army at 35 percent, and the Marine Corps at 26 percent, researchers report in JAMA Surgery.

Falls were the most common cause of non-battle injuries, accounting for 21 percent of cases, followed by car crashes at 19 percent and heavy machinery or equipment accidents at 13 percent, researchers report in JAMA Surgery.

Another 11 percent of injuries off the battlefield were from blunt trauma, and sports and gunshot wounds each accounted for another 7 percent of cases.

These injuries are also becoming more common. Researchers estimate that 41 percent of injuries between 2015 and 2022 will occur off the battlefield.

Many of these accidents may be preventable, lead study author Dr. Tuan D. Le of the U.S. Army Institute of Surgical Research said by email.

One limitation of the study is that it included people seriously injured enough to be sent to the hospital, and excluded more minor cases as well as fatalities that happened before service members could reach a hospital, the authors note.

Dr. Todd Rasmussen, author of an accompanying editorial and a surgeon at Walter Reed Medical Center in Bethesda, Maryland, told Reuters Health by email that deployment conditions often make everyday tasks more dangerous than they would be in civilian life, and this contributes to injuries off the battlefield, Rasmussen, a colonel in the U.S. Air Force, said by email.

“In the deployed environment, even basic activities such as driving a vehicle, working on a logistics or maintenance mission, or even working out are not routine,” said Rasmussen, who is a colonel in the U.S. Air Force.

He added, “Mission-critical activities need to be accomplished in adverse environmental conditions (e.g., heat, dust storms, snow and ice) and in areas with little if any normal infrastructure (e.g., safe roads, utility and electric grids or communication systems).”

“These mission-critical activities are often completed by relatively young troops facing fatigue and possibly even psychological stressors,” Rasmussen added. “Couple this with the urgency of the mission, and it’s not surprising that unintended situations account for a good portion of injured service members.”

SOURCE: bit.ly/2M2vOBC JAMA Surgery, online May 30, 2018.