In recent years, some scientists and advocates have warned that playing contact sports like football and hockey may increase the risk of brain diseases like Alzheimer’s disease or chronic traumatic encephalopathy (CTE) due to a buildup of a specific protein in the brain.

But a new Northwestern Medicine study of 174 donated brains, including some from former high school and college football players, pumps the brakes on that theory.

“The long and short of it is no, this protein in this specific brain region is not increased in people who played football at the amateur level. It throws a little bit of cold water on the current CTE narrative,” said corresponding author Dr. Rudolph Castellani, professor of pathology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neuropathologist.