It shouldn’t be a surprise that bicycle helmets help protect riders. But now California researchers have found who is more likely to get injured when they don’t wear one — men, minorities, and children.

Only 22% of adults and 12% of young riders who suffered head and neck injuries were wearing helmets, Charles R. Drew University of Medicine and Science in Los Angeles researchers found.

The researchers analyzed data from the National Trauma Data Bank between 2002 and 2012, which involved about 76,000 cyclists who had been injured — 81.1% male and 18.9% female. Women had a higher percentage of helmet use at 28% compared with men at 20%.

The study appeared in a recent issue of Brain Injury.

More than 53% of those studied suffered a serious or critical injury, with 15% reporting minor injuries.

Of those cyclists who suffered head and neck injuries, men were 36% more likely to die than women. Black and Hispanic people had longer hospital and intensive-care stays and higher mortality than white people, the researchers found.

About 67 million U.S. residents use bicycles. In previous studies, wearing a helmet has been shown to protect against serious injury and death. Yet, fewer than half of children and adults report using helmets.

The refusers reported the helmets were “uncomfortable” and “annoying,” according to the study.

The researchers suggest that mandatory helmet laws could improve injury and mortality rates due to bicycling accidents.

In Pennsylvania, the number of bicycle crash fatalities has nearly doubled in the five years between 2013 and 2017, from 11 in 2013 to 21 in 2017, according to the Pennsylvania Department of Transportation’s most recent report. Total crashes, however, went from 1,383 in 2013 to 1,141 in 2017.

The state requires children under age 12 to wear a helmet when operating a bicycle or riding as a passenger. If they are cited for not wearing a helmet, the $25 fine can be waived and the charges dismissed if the offender gets a helmet before the hearing. There is a religious exemption for helmet use, according to PennDot.

Despite the law, more than 20% of the fatalities and injuries in the state involved children 5 to 14 years old. Five of the 21 fatalities in 2017 were in this age group, according to the PennDot report.

“The State Police encourage residents of the commonwealth to utilize the proper safety head gear when bicycling,” said Trooper Brent Miller, a Pennsylvania State Police spokesperson. “It could potentially save your life and reduce the risk of serious head injury.”