A new research shows that the rate of brain injuries increase with the bike-share programs.

For the study, the American and Canadian researchers analyzed ten cities - five with bike-share programs and five without. The cities included Montreal, Washington D.C., Minneapolis, Boston, and Miami Beach.

The team gathered the information from trauma centers in the cities before and after bike programs started. The researchers found a 14 percent increase in bicycle-related head injuries in cities with such programs and no increase of such injuries was reported in the cities without the programs.

Researchers noted that the bike riders who do not wear helmets were more susceptible to such injuries.

"Certainly the data are solid enough that we need to look more carefully at these kinds of programs," said Andrea Gielin, director of the Johns Hopkins Center for Injury Research and Policy, reports NPR. "I think it's an important study that raises some concerns that we need to pay attention to. When we're trying to promote more bicycling, we need to do that in the context of increasing helmet use."

The reason for the study, researchers explained, was they wanted to find out the incidences of bicycle-related head injuries in North American cities with bike-share programs because helmet rentals are not given with the bikes. Following this, the researchers said that helmet availability should be included into bike-share planning and funding.

The study, 'Public Bicycle Share Programs and Head Injuries,' was published in the 'American Journal of Public Health.'