The National Institutes of Health (NIH) has decided to end its relationship with the National Football League (NFL), despite millions of unspent dollars still being on the table. This news came only days after the results of a major study on chronic traumatic encephalopathy (Cte) were revealed by Boston University.

NIH ends relationship with NFL

Almost five years ago the NFL announced that they had donated $30 million dollars to the NIH as part of a partnership. This move has often been touted as the single largest donation in NFL history. At the time Commissioner Roger Goodell promoted the move as part of the league's commitment to help fund independent science to look into the connection between football and brain disease, most notably, CTE.

However, officials from the NIH, which is a government agency, apparently decided to end their relationship with the league months ago.

The agreement between the two sides is now set to expire on August 31st, with the NIH still having $16 million dollars unspent from the NFL. ESPN's "Outside the Lines" reported that the disagreement between the two sides stems from a 2015 incident. This was when the league backed out of a major study awarded by NIH to a group lead by Robert Stern, researcher that has been critical of the NFL. The NFL then unsuccessfully tried to rescind funding to Stern, leading to growing mistrust between the NFL and NIH.

Recent CTE study not helping NFL's stance

The recently released study on the major link between former NFL players and CTE, was done by Boston University and led by Ann McKee, a neuroscientist at the school.

That study found that 177 of the 202 brains of football players studied (87.6%) have CTE. For the brains of former NFL players, 110 of the 111 (99%) brains studied had CTE. For the remaining results 48/53 college players, 9/14 semi-professional players, 7/8 CFL players, and 3/14 high school football players also had it.

However, the report cannot confirm that CTE is common in all football players since the players or families who donated the brains likely knew that something was wrong with them due to mental issues or concussions.

McKee noted that researchers were uncertain how much lifestyle factors could factor into the results. It also raised more questions, like commonality, or possible genetic risk factors, that could only be answered by doing more researcher on former players' brains.