While the topic of traumatic brain injuries in sports has gained national attention in recent years, most of the focus has been paid to preventing these injuries in high school, college, and professional level football due to their aggressive playstyle. But, a new study of NFL players suggests long-term damage may be done well before then.
The study of 40 former NFL players between the ages of 40 and 65 found that those who began playing tackle football before the age of 12 faced notable higher risk of altered brain development compared to those who waited until they were older to participate in contact football.
The results, published by researchers at Boston University School of Medicine and Brigham and Women’s Hospital, are the first to demonstrate an association between repetitive head impacts early in life and structural brain changes later in life, according to the researchers.
With growing concern over brain injuries in football, participation in youth leagues has been declining over the past years. These results, published online in the Journal of Neurotrauma, show making children wait to join the football team may be the right call, however the study team’s leader, Dr. Robert Stern suggested taking the findings with a grain of salt.
He cites the small number of players included in the study and emphasized the study only included those who went on to also play professional football.
“But it is a beginning,’’ said Stern, a professor and director of the BU Alzheimer’s Disease Center and director of clinical research for the school’s Chronic Traumatic Encephalopathy Center. “What it tells us is that we need to think rationally about when is it more or less likely that sustaining repetitive hits to the head [as children] will result in later-life problems.’’
The team says the study bolstered evidence of a “critical window” of brain development between the ages of 10 and 12 -when children’s brains may be particularly susceptible to injury.
“This development process may be disrupted by repeated head impacts in childhood possibly leading to lasting changes in brain structure,” said Julie Stamm, who conducted the study as part of her doctoral dissertation at BU and now is a post-doctoral fellow at the University of Wisconsin School of Medicine and Public Health.
All players included in the study had more than 12 years of organized football experience, including a minimum of two years participating in the NFL. Half of the players participated in tackle football before the age of 12, while the other half began playing at 12 or older. The players were matched so the number of concussions was similar among both groups.
The former players underwent advanced magnetic resonance imaging (MRI) exams of their brains so the researchers could assess the movement of water molecules in so-called “superhighways” which are essential for relaying commands and information in the brain.
The researchers said the results indicated the players who started playing football before the age of 12 were significantly more likely to exhibit changes in the largest structure of the brain that connects the two cerebral hemispheres.
While these findings may raise concern about the risk for long-term brain damage for children who play tackle football at young ages, the study’s authors say the findings may be significantly different if they examined a group of youth or school-aged players, rather than veterans of the sport.
“The results of this study do not confirm a cause-and-effect relationship, only that there is an association between younger age of first exposure to tackle football and abnormal brain imaging patterns later in life,” said Martha Shenton, a professor and director of the psychiatry neuroimaging laboratory at Brigham and Women’s.