Study: Contact Sport Athletes At Least 68 times More Likely to Develop CTE Than Non-Contact Sport Athletes

Researchers Find Conclusive Evidence That Repetitive Head Impacts Cause CTE

By Ken Reed

When it comes to brain trauma and CTE in sports, the research is showing that we’ve put too much emphasis on concussions.

For a long time, parents, coaches, players, members of the media and some doctors have blamed concussions for causing chronic traumatic encephalopathy (CTE), the brain disease often linked to contact sports like football and hockey.

To be sure, concussions are never good, but the fact is, research has revealed for some time now that it is repetitive sub-concussive blows to the brain that lead to the neurodegenerative disease commonly known as CTE.

An analysis done by leading international experts on chronic traumatic encephalopathy (CTE) found conclusive evidence that repetitive head impacts (RHI) cause the degenerative brain disease CTE. Another key finding in the study was that contact sport athletes were at least 68 times more likely to develop CTE than those who did not play contact sports.

Researchers from Harvard University, Boston University, University of Sydney (Australia), University of Auckland (New Zealand), University of Michigan, University of California-San Francisco, University of Sao Paulo (Brazil), University of Melbourne (Australia), Oxford Brookes University (UK) and the Concussion Legacy Foundation have issued a global call to action to sports organizations, government officials, and parents to immediately implement CTE prevention and mitigation efforts, especially for children.

The researchers analyzed the data through the “Bradford Hill criteria”, a trusted set of nine benchmarks developed by one of the pioneers of smoking and lung cancer research to gauge the confidence science can place in a causal relationship between an environmental exposure and an adverse health outcome.

“Even we were surprised by how strong the causal relationship between repetitive head impacts and CTE becomes when the data are analyzed within the appropriate framework and in an unbiased manner,” said study co-senior author Dr. Robert Cantu, Concussion Legacy Foundation medical director. “Scientists and policymakers must retire the word association and begin using causation in all forums in an urgent effort to educate the public.”

This study’s findings are consistent with findings from previous studies.

One of the implications of the studies pinpointing repetitive head impacts is that the current focus on concussion prevention and treatment protocols, while positive, really doesn’t fully address the development of CTE.

“The cumulative effect (of sub-concussive hits), when the brain is not fully healed, particularly in younger people, is really, really damaging, and that’s the problem,” said Dr. Lee Goldstein, an associate professor at Boston University’s School of Medicine and College of Engineering.

— Ken Reed, Sports Policy Director, League of Fans