New Harvard-led study links earlier tackle football start to worse brain health 50 years later

Findings elevate concerns about exposing children’s developing brains to hundreds of head impacts a year

BOSTON, MA – A new study from Harvard and Boston University researchers sounds a new warning on the risks of youth tackle football participation. Published in the Journal of Neurotrauma, the study examined 677 deceased former football players. Among those who died at 60 or older, families reported worse cognitive, behavioral, and neuropsychiatric outcomes in players who began tackle football at a younger age. Among this older group, each year younger they began playing football was associated with 10% greater odds of memory impairment that impacted their daily lives.

The study may help provide insight into why research on the long-term effects of pediatric repetitive head impacts in football players is mixed. Studies of middle-aged former youth football players do not always find an association between a younger start and brain health. This study suggests that symptoms may take decades to develop.

“It makes biological sense that brain damage from pediatric repetitive head impacts in tackle football may not fully manifest until decades later,” said Dan Daneshvar, MD, PhD, Chief of Brain Injury Rehabilitation in the Department of Physical Medicine and Rehabilitation at Spaulding Rehabilitation and Harvard Medical School. “I see the same thing in my patients who played contact sports that impacted their knees, hips and shoulders – the worst symptoms of progressive arthritis don’t appear until decades later.”

Among the 677 former players, 471 (70%) had CTE, but the association with earlier onset of symptoms was also present in the 30% without CTE. Associations were strongest in older participants, indicating that early exposure may reduce neurological resilience that only becomes apparent decades later. The research suggests that the developing brain may be particularly vulnerable to repetitive head impacts, with effects that manifest later in life.

“There is substantial evidence of repetitive head impacts being the primary risk factor for CTE,” said Michael Alosco, PhD, Co-Director of Clinical Research, Boston University CTE Center. “Now, it’s important to understand what can change to reduce that risk. The data should inform youth sports policies aimed at reducing early exposure to repetitive head impacts.”

While the presence and severity of clinical symptoms was associated with age of the first year of tackle football, age was not associated with the presence of CTE. The only known risk factor for the presence of CTE, to date, is years of football participation. The more years played is associated with greater odds of having CTE. The finding was also independent of years of football play, despite most players in the study going on to play in college or the NFL.

As with all brain bank studies, the findings apply to individuals who donated their brains and may not represent the general population of former players.