It's been established by several research studies that playing American football can cause head trauma and lead to dementia, Alzheimer's disease and chronic traumatic encephalopathy (CTE) What hasn't been well understood is how the risks are related to age.
Researchers at Boston University School of Medicine, which is the epicenter of concussion and head injury research, have recently published a study that looks at the age of players when they first began the game and their risk of cognitive, behavioral and emotional issues later in life.
Researchers began the study by conducting clinical interviews with family members and friends of 246 football players who had passed away. After collecting data on the age when the athletes first began playing the game and the first onset of concussion-related symptoms, there was a clear relationship between the factors. Players that started the game before the age of 12 developed symptoms an average of 13 years sooner than players who didn't get into the game until after age 12.
Michael Alosco, an assistant professor of neurology at Boston University School of Medicine, and lead author on the study explained, "Thirteen years is a huge number. The younger they started to play football, the earlier these symptoms began. There is something unique about the age you start playing football. There is something about it that is contributing to those symptoms" Alosco also noted that some of the players had first started tackle football when they are 5 or 6 years old.
The numbers were crunched by the team, who controlled for factors like total years of play, level of play, and styles and rules that were in place when the athletes began the game. They found that for every year younger that any given player started playing, there was a 2.4 year earlier onset of cognitive issues and a 2.5 year earlier onset of behavioral or emotional problems.
The researchers began the work believing that players who started the game at a younger age would have increased pathology in the brain, but that was not the case. Also, the earlier onset of cognitive and behavioral issues was the same regardless of whether or not a player had a diagnosis of CTE.
Professor Alosco pointed to the critical amount of development that is happening in the human brain as evidence for holding off on tackle football until after age 12. He wrote, "Those are the ages where the gray matter of your brain is really growing, the vasculature of your brain is really growing, the connections between neurons are forming. Neurodevelopment is really at its peak." Dr. Ann McKee, who is the director of BU's CTE Center said the research was a warning to all athletes, stating, "This finding wasn't just for people who died of CTE, this was for people with any disorder that affected their cognition, behavior, or mood. Early exposure made them more susceptible to any later life pathology." The video below talks more about the problem of youth football and head injury, take a look.