The corresponding author of a new study suggesting a correlation between cumulative hits to the head from youth, high school and college football and later-life impairments is urging caution when interpreting the results, emphasizing more research and a larger sample size is needed.
“The key finding with this study is there is a very clear and strong dose-response relationship,” Dr. Robert Stern told USA TODAY Sports in advance of the study’s publication Thursday in the Journal of Neurotrauma. “But it’s the first step in looking at causation.”
The study was part of dissertation work by one of Stern’s PhD students at Boston University, Philip Montenigro, who is the paper’s first author.
It used existing, published data from hit sensors in helmets to create a “cumulative head impact index” for estimating the number of hits taken by position and level of play. The index was then applied to 93 former football players who participated at no higher than the college level, played no other contact sports and underwent evaluation that included a standardized, telephone-based cognitive test and self-reported behavioral/mood tests as part of an ongoing, long-term study.
The initial findings showed a relationship between the index and later-life cognitive impairment, self-reported executive dysfunction, depression, apathy and behavioral dysregulation. But Stern stressed it’s just a starting point, with next steps including validating the index with further studies and examining other variables, such as genetic risk factors.
“We don’t want people thinking that, ‘Oh, man, I just played an extra year of high school football. Does that mean I’m going to have serious depression?’ No, that’s not how these results need to be interpreted,” Stern said. “The specific relationship for a specific individual is not known.”