Has there been any data collected as to if the danger is lessened at lower levels of competition (i.e. high school and younger) where the players are slower, smaller, and weaker?
Yes - and there is no proof that football even causes CTE in any large way - at any level. The much maligned "tau protein" that's used to diagnose CTE can be linked to all kinds of things - including alcohol, drugs, diabetes etc.
Unfortunately Americans have grown HIGHLY suggestible to media mentions of "studies" without even seeing if they are junk studies or not. Lots of people from lawyers to academics to politicians have made football (and the toxic males who play it) a mark. Its the "global warming" of sports.
Study of high school players find no link between years of play and decline in neurocognitive function
As more parents consider whether it's safe for adolescents to play football, a new Tulane University study of high school players found no link between years of play and any decline in neurocognitive function.
The results, which were presented at the 2014 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) in New Orleans on March 14, suggest risks of sport-related brain injuries are relatively low, said lead author Dr. Gregory Stewart, associate professor of orthopaedics at Tulane University School of Medicine.
https://www.news-medical.net/news/2...y-and-decline-in-neurocognitive-function.aspx