A new study from researchers at Boston University points to risks associated with youth tackle football. (Photo by Marvin Joseph / The Washington Post)

A new study suggests a strong correlation between the age at which some athletes begin playing tackle football and the onset of behavioral and cognitive problems later in life, findings that become significantly more pronounced for those who take up the sport before age 12.

Researchers concluded that for every year younger an athlete begins to play tackle football, he could experience symptoms associated with Chronic Traumatic Encephalopathy 2½ years earlier. Those who begin playing before age 12 could start experiencing symptoms more than 13 years earlier.

The study was published Monday in the Annals of Neurology journal and was conducted by researchers with the Boston University School of Medicine and the VA Boston Healthcare System, including some of the leading CTE researchers, such as Dr. Ann McKee, Dr. Robert Stern and Dr. Robert Cantu. The lead author was BU’s Dr. Michael Alosco.

The study comprised 246 deceased football players who had donated their brains to the brain bank run by the VA, Boston University and the Concussion Legacy Foundation. Of that group, 211 were diagnosed with CTE.

While the research did not find a “statistically significant” connection between the age of first exposure and the severity of CTE later in life, the study says “youth exposure to tackle football may reduce resiliency to late life neuropathology.”

The researchers warned the results might not be representative of the broader population of football players. It did not include a control group and could suffer from ascertainment bias, meaning families might have been more likely to donate a loved one’s brain posthumously if they suspected something was amiss.

The study results were not impacted by the level of play and included those who had played football in high school, college and professionally. Researchers found that even the former players who were not diagnosed with CTE experienced an earlier onset of behavioral and cognitive impairments the earlier they took up the sport, “suggesting that the relationship between younger [age of first exposure] to tackle football and longterm neurobehavioral disturbances may not be specific to CTE,” the study says.

While CTE, like most neurodegenerative diseases, cannot currently be diagnosed in a living person, the symptoms surface earlier and become more pronounced as the person ages, often in the form of behavioral and mood issues followed by cognitive impairment.

“Youth exposure to repetitive head impacts in tackle football may reduce one’s resiliency to brain diseases later in life, including, but not limited to CTE,” McKee, the director of Boston University’s CTE Center, said in a statement. “It makes common sense that children, whose brains are rapidly developing, should not be hitting their heads hundreds of times per season.”

Research on traumatic brain injuries related to sports is a burgeoning field, particularly among youth athletes. Several recent studies have suggested head impacts before the age of 12 can be more damaging than those suffered by athletes who take up the sport later, though some research hasn’t found that age of first exposure is necessarily a contributing factor to cognitive functioning later in life.

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