The National Institutes of Health formally acknowledges that CTE is caused in part by repeated TBI
By Minghong Kim. This article was initially published in our Concussion Update newsletter; please consider subscribing.
The National Institutes of Health (NIH) — a US federal government agency that serves as the nation’s largest biomedical research center — recently acknowledged that there is a causal link between repeated blows to the head and chronic traumatic encephalopathy (CTE). “Research-to-date suggests (CTE) is caused in part by repeated traumatic brain injuries,” states the NIH.
This formal acknowledgment aligns the NIH with the United States Centers for Disease Control and Prevention (CDC), which states that while “understanding of the causes of CTE is currently limited, the research to date suggests that CTE is caused in part by repeated traumatic brain injuries, including concussions.” Now, two of the world’s leading medical research bodies–the NIH and the CDC–agree that CTE is caused, in part, by repeated traumatic brain injuries.
According to The Guardian, “the NIH’s change in guidance was made after a group of 41 leading scientists, doctors and epidemiologists” from the Concussion Legacy Foundation co-signed a letter to the National Institute of Neurological Disorders and Stroke (NINDS), a division of the NIH. The letter cited a review article published in July in Frontiers in Neurology that applied the Bradford Hill criteria to investigate a link between repetitive head impacts [RHI] and CTE. The Bradford Hill criteria is “a framework to determine if one can justifiably move from an observed association to a verdict of causation.” The authors of the review article concluded that “we have the highest confidence in the conclusion that RHI causes CTE.”
Thus, the Concussion Legacy Foundation urged the NIH to update its official statement on CTE causation, writing that “if the NINDS and CDC were aligned on causation of CTE, we believe this (alignment) would ignite interest in CTE prevention, research into pathogenic mechanisms of CTE, diagnosis during life, and effective treatments.”
However, the NIH and the CDC’s position on CTE causation clashes with the one held by the influential Concussion in Sport Group (CISG), which is supported by the International Olympic Committee, FIFA, and World Rugby. CISG has published consensus documents that have “consistently played down the connection between CTE and brain injuries sustained in sport, a position that has been used by many sports federations as they defend themselves against legal challenges and calls to reform.”
On October 27 and 28, CISG convened in Amsterdam for its 6th International Consensus Conference on Concussion in Sport. The group has begun drafting a new version of the consensus statement, which they will publish early next year. Whether CISG will change its position on CTE, repetitive head impacts, and traumatic brain injuries in its new consensus statement remains to be seen.