Adult athletes aren't the only ones at risk of long-term damage from jarring collisions during games. Lasting brain damage can occur after playing high school football for just a few years, a new study says. Researchers found such injuries to six young men who played football in high school, but stopped before college and didn't play professionally. Young hockey and soccer players also can be affected by repeated contact that causes concussions. “It starts with a whole bunch of hits, but it sets in motion the disease that gets worse and worse as someone gets older," explains Dr. Robert Stern, part of the study team at Boston University School of Medicine.

Last week's report in a science journal called Brain suggests a strong link between degenerative brain disease and serious head trauma. Eighty percent of men in a test group, all of whom played sports, had symptoms of a disease that can cause depression, memory loss and dementia long before a person is elderly. This adds to evidence of possibly severe consequences from routine hits to the head in sports. Severity and frequency of head trauma must be taken into account when assessing risk, the Boston researchers emphasize.

Concussions are just part of the problem. "All concussions are not created equal," says Robert Cantu, an author of the four-year study. He and colleagues don't know how much repeated brain trauma can cause the degenerative disorder, though Canto adds: "There is no available evidence that occasional, isolated or well-managed concussions trigger it." By "well-managed," he means not letting a player back in the game for at least several days after a hard hit to the head. Hospital checkups are recommended in most cases. Ohio senators are considering legislation that would require coaches or referees to remove a player from a game or practice if the athlete shows signs of a concussion or is suspected of having one. They'd need medical approval to play again. The bill also requires training to help coaches and refs spot head injury symptoms.

Teen player says: "Doctors say I should drop out of my contact sports or just limit it to one. I am disappointed because I want to play my sports.” -- Patrick O’Halloran, 13, of Bostron, who plays football, hockey and baseball

Researcher says: "If you consider this 'a concussion problem' it seems solvable. That's not the truth." -- Chris Nowinski, Boston University study co-author

Sports columnist says: "Calling the head-injury crisis a concussion crisis made it sound as if it stemmed from how the game is played, not from the game itself. Football is an inherently violent sport in which unremarkable plays can eventually add up to permanent brain damage." -- Jonathan Mahler, Bloomberg View