A study of University of Wisconsin Hospital trauma patients found that motorcyclists who don't wear helmets are twice as likely to suffer neck injuries in crashes compared to those who use helmets.
The study looked at more than 1,000 patients who'd been treated for motorcycle crashes from 2010-15, the Wisconsin State Journal reported. Almost 70 percent of patients hadn't worn helmets.
More than 15 percent of those who hadn't worn helmets suffered neck injuries, including almost 11 percent with spinal fractures.
Just over 7 percent of riders who used helmets injured their necks, including almost 5 percent with spinal fractures.
"The helmet seems to be protective to these types of injuries," said Dr. Nathanial Brooks, an associate professor of neurological surgery at the UW School of Medicine and Public Health and an author of the study.
The university's study was published in the Journal of Neurosurgery: Spine this month.
The study counters laboratory research from 1986 and 2011 that argue that the weight of a helmet can make the neck more vulnerable to injuries.
"The goal of our study was to look at real-world situations, rather than the lab situations," Brooks said.
Wisconsin only requires riders 17 and younger to wear helmets. It's one of 28 states that have partial motorcycle helmet laws, according to the Insurance Institute for Highway Safety.
A Wisconsin motorcycle rights group opposes the helmet requirement and argues that it should be an individual decision.
"It's up to an adult to be able to choose," said Dave Charlebois, executive director of ABATE of Wisconsin.