By Jonathan Kaminsky
(Reuters) - Former NFL players who began playing tackle football before age 12 are more likely to suffer from memory and thinking problems than those who took up the game later, a new study has found.
The findings, published on Wednesday in the scientific journal Neurology, come amid heightened concerns over the effects that playing the physically punishing sport can have on the brain.
The National Football League has agreed to pay up to $5 million to each former player developing neurological impairment in a settlement that is under judicial review. Most of the 20,000 former players involved in a class-action lawsuit against the NFL back the deal, while others think the league should pay more.
"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," study author Robert Stern, a neurologist at Boston University, said in a statement. "If larger studies confirm this association, there may be a need to consider safety changes in youth sports."
Since the study focused on NFL players, the results may not extend to the general public, and more research is needed, he added.
The study consisted of 42 former NFL players with an average age of 52, all of whom had experienced memory and thinking problems for at least six months. Half the players started playing tackle football before age 12, with a similar number of concussions sustained between the two groups.
The researchers found that those who started playing earlier performed "significantly worse" on all test measures, including remembering words from a list they had been given 15 minutes earlier.
"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," said Christopher Filley, a University of Colorado neurologist, in an editorial accompanying the study.
He added that because the study could not take into account the precise number of hits each player absorbed, the results might be a reflection of more overall blows to the head rather than early exposure to football.
The NFL and the NFL Players Association did not immediately respond to messages seeking comment.