Former National Football League (NFL) who played tackle football were found to be more likely to suffer memory and thinking problems later in life.
The findings could ultimately lead to changes in the safety protocols used in youth sports, the American Academy of Neurology reported.
"Our study suggests that there may be a critical window of brain development during which repeated head impacts can lead to thinking and memory difficulties later in life," said Stern. "If larger studies confirm this association, there may be a need to consider safety changes in youth sports."
A research team looked at 42 former NFL players with an average age of 52, all of which had struggled with memory and thinking problems for at least six months prior to the study. Half of the players participated in tackle football before the age of 12 and half did not and the number of concussions suffered was relatively equal in both groups.
The researchers found the study subjects who had participated in tackle football before the age of 12 performed significantly worse on all test measures such as recalling words from a list.
"Football has the highest injury rate among team sports," said Christopher M. Filley, with the University of Colorado School of Medicine in Aurora, CO, in an accompanying editorial.. "Given that 70 percent of all football players in the United States are under the age of 14, and every child ages nine to 12 can be exposed to 240 head impacts during a single football season, a better understanding of how these impacts may affect children's brains is urgently needed."
The researchers noted that since the study focused on NFL players, the study's results may not necessarily be applicable to the general public, and more research will be needed before any policy changes are enacted.
"While the researchers did take into account the total years of football played, they were unable to assess the total number of head impacts. So it's possible that the number of impacts is responsible for the reported results rather than the early age of exposure to football," Filley concluded.
The findings were reported in a recent edition of the journal Neurology.
