Kids who start playing tackle football before the age of 12 are at much higher risk of developing behavioral and emotional troubles as adults, according to a new study.
Researchers found much higher rates of depression, apathy and other neurological problems among those who started young — whether or not they suffered concussions.
Dr. Robert Stern of Boston University's Chronic Traumatic Encephalopathy Center tells Here & Now's Jeremy Hobson about the risks of repeated hits to the head.
On how they conducted the study
"This is a study of adults who were participating in a project called the [Longitudinal Examination to Gather Evidence of Neurodegenerative Disease] LEGEND study, and the average age was around 51 years old when they participated. And they had undergone a variety of cognitive tests on telephone interviews, and they filled out these questionnaires about depression and behavior and apathy, things like that, on the web. We asked them a lot about their history of playing sports, and this group were ones who only played football as their main sport. And there were people who played up through high school, up through college and then also some people who played through the pros.
"And we found out how many of them started playing tackle football before age 12 and compared that group to the ones who started at age 12 or older, and looked at how they are doing now as adults on all those different types of tests."
On the findings for those who had started playing at an age younger than 12
"In this case, they had a range of mood and behavior problems, and what we call executive dysfunction, or problems with initiating and planning, organization. So we weren't looking at the brain, per se, in this study. We've done that in the past with another study looking at this age of starting to play where we actually had brain scans. But in this case it was just how are they functioning, what are their symptoms like as adults?
"And the answer is that these folks who started to play tackle football before age 12 had a threefold increased odds of having clinically meaningful depression symptoms and twofold clinically meaningful apathy and behavioral dysregulation, meaning not being able to control their behaviors and their impulses, as well as self-reported difficulties with this executive functioning."
On the study not looking at only those who sustained concussions, but rather anyone who played
"We're not looking to concussions, we're not as concerned about the symptomatic concussions when it comes to long-term consequences.
"What we're really concerned about, and what I think people really need to start being concerned about, is this exposure to what we refer to as sub-concussive hits: these hits that don't necessarily result in the symptom right then, but people can get hundreds of them a year. Kids, youth, on average, have been found to have between 500 and 600 a year of these types of hits."
"We do all kinds of crazy things to make sure that they're healthy ... And then we drop them off at a field and put these helmets on and say, 'Hit your head over and over again, 500, 600 times per season.' "Dr. Robert Stern
On whether it mattered how long people played
"It didn't, and we statistically controlled for the number of years that everyone played. So it wasn't just that by starting younger they had more years of play. So, it wasn't the number of years. It also wasn't how high a level they played. So the same finding held true whether they played only up through high school, or whether they played up through college, or whether they played in the pros."
On what's happening at the biological level
"That's what we're trying to figure out. You know, there's a couple of things going on. Our group looks at this neurodegenerative disease CTE, chronic traumatic encephalopathy, which is kind of like Alzheimer's disease, but it's a unique disease, and it seems to start at that period of time when people are getting hit over and over again, and we're trying to understand exactly what the mechanism is. In this case, for this study, the concept is that we know from a lot of neuroanatomy research and development research that the brain is undergoing this incredible maturation and growth in the years between around 9 and 12 in boys. And so the feeling is that if it's going through all that growth and they're subject to getting hit after hit after hit, maybe that has some kind of long-term consequence, that there's this period of vulnerability in the brain's development."
On the significance of the age of 12 in the study
"It's based on previous research of ours, also, where we looked at just former NFL players, and we looked at really in-depth neuropsychological testing as well as brain scans and found changes in the integrity of their brains between the ones who started before 12 or 12 or older. But we chose it because of the understanding of the peak periods of development, the previous research, but we also in our study now looked at 11, looked at age 13, and 12 led to the most robust findings."
On the culture of youth football and starting to play football at a young age
"Oh, they start really, really young. Pop Warner, USA Football. These kids start at age 5 and 6 putting on these big helmets with facemasks that, you know, make them be bobbleheads. They can barely hold themselves up and yet then they're asked to do these drills where they're hitting their heads against each other, time after time after time. There's around over a million youth tackle football players in our country."
On his advice
"I don't think a single study really should determine policy change or dramatic recommendations, it's the growing evidence. But here's the thing. You know, we parents do all kinds of things to protect our kids. We do all kinds of crazy things to make sure that they're healthy, they don't have injuries, that they reach their full potential. And then we drop them off at a field and put these helmets on and say, 'Hit your head over and over again, 500, 600 times per season,' at a time when their brains are growing and developing that most precious organ in our body.
"So, my recommendation is, think about that. You know, we can't take our kids away from athletics and exercise and sports. That's critical. They need to have that kind of exposure to great things, and physical and emotional benefits. But we need to remove their exposure to hits to the head over and over again."
On how the national conversation about football's risks might change
"I never know. I really never know. Again, the science is really in its early stages. We don't have definitive understanding of a lot of these things. The brain is so unbelievably complex, and we've just started looking at these long-term consequences of repetitive hits to it. I have no idea if this is going to change the conversation, move it forward, there's going to be less or more people playing. The study itself should not have that dramatic an impact. The conversation needs to be one of logic: Should we be exposing kids to repetitive brain trauma while their brains are developing?"
On potential variables in the study
"There's all kinds of potential variables that could have clouded the findings. So we tried to statistically control for all those things. Can't control for everything. So we look at their age, their education, their number of years they played, things like that. We looked at learning disabilities because sometimes people have criticized work like this saying, 'Well, maybe it was kids with already vulnerable brains.' So we statistically controlled for learning disabilities. The same findings came out. There are so many potential possible reasons that what we're seeing may not be true. We tried to deal with that as much as we can, and the findings were pretty striking."
This article was originally published on September 19, 2017.
This segment aired on September 19, 2017.