THURSDAY, June 12 (HealthDay News) -- In the two years after Pennsylvania repealed its universal motorcycle helmet law, there was a 32 percent increase in motorcyclist head injury deaths and a 42 percent increase in head injury-related hospitalizations, a University of Pittsburgh study says.

The state's universal helmet law was repealed in 2003. Currently, only riders under age 21 and those with less than two years' experience who haven't taken a safety course are required to wear helmets.

The researchers analyzed data from the state's health and transportation departments for the years 2001-02 and 2004-05 and found helmet use by motorcyclists involved in reported crashes decreased from 82 percent to 58 percent in the two years after the helmet law was repealed.

While the head injury death rate increased by 32 percent, there was no increase in the non-head injury death rate.

Along with the 42 percent increase in head injury-related hospitalizations after the repeal of the helmet law, there was an 87 percent increase in the number of head-injured, hospitalized motorcyclists who required further care at facilities specializing in rehabilitation and long-term care.

Total acute care hospital charges for motorcycle-related head injuries increased 132 percent in the two years after repeal of the law, the study found.

The study was published online Thursday in the American Journal of Public Health and was expected to be in the August print issue.

"This relatively large increase in head injury deaths and hospitalizations after the repeal suggests that the (universal helmet) law was protecting riders," lead author Dr. Kristen Mertz, assistant professor in the department of epidemiology at the University of Pittsburgh Graduate School of Public Health, said in a prepared statement.

"Our findings strengthen the argument for more comprehensive helmet laws that help protect riders and lower the cost of health care," study co-author Hank Weiss, associate professor in the department of neurological surgery at the Center for Injury Research and Control, University of Pittsburgh, said in a prepared statement.

"Serious head injuries, causing anything from short-term memory loss, inability to concentrate, to coma and death, can severely impact quality of life and affect not just those injured, but their families as well," Weiss said.

Only 20 states have laws that require all motorcyclists to wear helmets.

More information

The U.S. National Highway Traffic Safety Administration has more about motorcycle safety.