Researchers say they can show that brain inflammation from football head trauma may lead to the development of chronic traumatic encephalopathy, the devastating degenerative brain disease.
Inflammation can persist
And the longer someone plays contact sports, the greater the odds for chronic traumatic encephalopathy (CTE), the study authors concluded.
"This study provides evidence that playing football for a prolonged period can result in long-term brain inflammation, and that this inflammation might lead to CTE," said study first author Jonathan Cherry. He is a postdoctoral fellow in neurology at Boston University School of Medicine.
"Although inflammation may be protective in the brain especially right after an injury, our study suggests that years after a period of playing football, inflammation can persist in the brain and is linked to the development of CTE," Cherry said in a university news release.
CTE, a progressive brain disease, is thought to arise from repetitive head trauma, such as multiple concussions or even sub-concussive impacts. It can only be diagnosed during an autopsy.
For this study, the researchers analysed the brains of 66 deceased professional and college football players, as well as the brains of 16 non-athletes, looking for signs of cell damage and inflammation – swelling. The investigators also examined how long each athlete played the sport alongside degree of inflammation, CTE severity and dementia.
A predictive biomarker
Using a computer model, Cherry's team said it found that those who played football longer had greater inflammation. However, the study can't prove a direct cause-and-effect relationship.
The findings were published online in Acta Neuropathologica Communications.
In a related development, Boston University researchers said they discovered advanced CTE in the brain of former pro football player Kevin Turner, who died in March at age 46. They said this damage likely led to his early death from complications of amyotrophic lateral sclerosis (ALS), which is also called Lou Gehrig's disease. Turner, a fullback, played for the Philadelphia Eagles and New England Patriots.
The researchers next want to learn whether treating brain inflammation could help prevent CTE or lessen its severity.
Also, Cherry said, "Brain inflammation could be used as a predictive biomarker to help identify patients at risk of developing CTE in life."
Last year, Boston University researchers confirmed CTE in the brains of 87 out of 91 deceased former National Football League players tested.
Inflammation is thought to play a role in other brain-related diseases such as Alzheimer's disease, Parkinson's disease and ALS, Cherry and colleagues said in background notes.