Concussion rates for American high school athletes more than doubled from 2005 to 2012, according to Ohio State University researchers.
But scientists don't think this means sports are becoming less safe. Rather, heightened public awareness may mean concussions are reported more than they used to be.
"It's scary to consider these numbers because at first glance it looks like sports are getting more dangerous and athletes are getting injured more often," Dr. Joseph Rosenthal, lead author of the study, which appeared last month in the American Journal of Sports Medicine, said in a statement. "This study is observational, so it doesn't offer any proof about why the rates are going up. But I think in reality it's showing that concussions that were occurring before are now being diagnosed more consistently - which is important."
The researchers analyzed seven years of data from 100 high schools nationwide. The schools are part of the High School Reporting Information Online program, which monitors teen sports injuries. Scientists noticed concussion rates especially jumped after the 2008-09 school year, which was when states began passing laws requiring concussed athletes to sit out until a doctor approved their return to sports.
The study found that the number of concussions per 1,000 athlete exposures in 2012 was 0.51, more than doubling the rate of 0.23 in 2005. The total number of concussions high school athletes sustained from 2005 to 2012 at the 100 high schools surveyed was 4,024.