A new study from the Journal of the American Medical Association shows that e-scooter injuries have increased dramatically nationwide in the last year.

Researchers with the University of California San Francisco evaluated data from emergency rooms across the U.S. and determined that between 2014 and 2018, 39,113 e-scooter injuries occurred and that there was "a dramatic increase in injuries and admissions from 2017 to 2018 associated with e-scooter use."

E-scooters are quickly becoming commonplace in Portland, but the study didn't specifically cite Portland data. Benjamin Breyer, one of the study's authors, says the injury data can't be separated out by city.

Nationwide, the study found that during the five-year period, the proportion of e-scooter-related hospital admissions for people 18 to 34 increased by 354 percent.

Related: E-Scooter Rider Is in Critical Condition After Wrecking While Crossing Northwest Portland Railroad Tracks

In 2018, 30 percent of e-scooter crashes led to head injuries while the most common types of injuries were fractures, contusions and abrasions.

"The nearly doubling of incident e-scooter trauma calls for improved rider safety measures and regulation," the study noted, adding that the percentage of e-scooter riders with head injuries was more than double that of bicyclists.

"E-scooter companies should facilitate and encourage helmet use by increasing helmet access," researchers wrote.

The study did not research the scenarios that caused the crashes, nor alcohol or helmet use.

Related: E-Scooter Rider Seriously Injured by Car in Southeast Portland

Portland is currently trying out e-scooters in a second pilot program. The trial started April 26, and last month the Portland Bureau of Transportation extended the program's end to Dec. 31, 2020. Six companies—Bird, Bold, Lime, Razor, Shared and Spin—are currently operating in Portland.

In 2019, PBOT wrote in a statement, the Multnomah County Health Department identified 183 e-scooter related emergency departments and urgent care clinic visits.