A study of e-scooter crashes during a three-month period in Austin, Texas showed nearly half resulted in head injuries and almost no one was wearing a helmet, according to research released Thursday at a Centers for Disease Control conference in Atlanta.

The study of the dockless e-scooters, similar to ones that just returned to the streets of Portland, was conducted between Sept. 5 and Nov. 18, 2018 in the Texas state capital.

The study cautioned that data on e-scooter crashes nationwide is limited even as rental programs begin to spread.

The researchers culled Austin Emergency Medical Service reports and narratives that contained the word "scooter" and systemic complaints in the Austin Public Health files. A list of individuals involved in crashes were then sent questionnaires, called or e-mailed.

Of 271 people contacted, 158 agreed to interviews and 130 confirmed they were in an e-scooter crash.

Of that latter group, half were male. The median age was 29. Some 45 percent had head injuries, 27 percent had upper extremity fractures and 12 percent a lower extremity fracture. One in 5 was hospitalized.

Half the crashes were on the street and 18 percent involved a motorized vehicle. Some 29 percent were first-time riders. Fewer than 1 percent of riders reported wearing a helmet.

"A high proportion of e-scooter related injuries involved potentially preventable risk factors, such as lack of helmet use, or motor vehicle interaction," the study concluded. "Interventions aimed at these risks and education to first-time riders could potentially reduce injury incidence and severity."

E-scooters re-appeared on Portland city streets in late April in the second year of an experimental phase on their feasibility. 

KGW traffic reporter Chris McGinness reached out to viewers for their take on e-scooters coming back to Portland city streets.

CNBC reported last March that the University of San Diego Medical Center tracked severe injuries admitted to its trauma center for 18 months.

Dr. Leslie Kobayashi, associate professor of surgery, said the center has admitted 42 patients for e-scooter related injuries in the past year, CNBC reported.

Ninety-eight percent of patients were not wearing a helmet. Forty-eight percent had a blood alcohol level above the legal limit for intoxication and 52 percent tested for an illicit substance, CNBC reported.