There is no doubt that the violence of professional football results in severe physical injury with long-term consequences. The evidence is compelling and undeniable.

The news media have covered extensively the initial denials by the National Football League (NFL) of such physical and mental injuries. However, the league has reluctantly assumed some culpability and just this week conceded that one third of its players will suffer some degree of brain trauma.

However, these news stories fail to mention the degree of similar cognitive dysfunction among athletes who participate in other sports with a high degree of risk for head injuries.

We know that soccer players suffer concussions albeit at a lower rate than football players.Female athletes are especially vulnerable according to research, because they have thinner necks than men and thus their brains are more prone to injury from sudden head movements.

The term “punch drunk” is a term long used to describe the mental impairment many boxers display from too many fights.

Hockey players, too, participate in a risky sport. Are there fewer injuries now that the skaters wear protective gear? Decades ago the head was the only part of their bodies uncovered during games.  Despite today’s helmets players still suffer head trauma often with prolonged dysfunction.

Although professional wrestling matches are scripted, the cumulative physical contact on the athletes can be negative.

Chris Nowinski, the executive director of the Sports Legacy Institute, has a personal interest in brain trauma. A former Harvard University football player, he suffered a number of concussions that forced his retirement from WWE professional wrestling.

Given all this, missing are rigorous studies comparing the ratio of mental and physical decline among professional football players with cohorts in the general population:

–What is the ratio between heavy offensive and defensive linemen to non-athletic obese males of similar age?

–What is the ratio between educational achievement or IQs of athletes with a similar group among the general population?  Some studies show a relationship between years of education and the risk for Alzheimer’s disease.

–What is the impact of long-term exposure to higher than average levels of adrenaline that professional athletes experience prior to and during games?

Adrenaline causes the fight-or-flight reaction when faced with danger and the high levels of the hormone reduces cognitive function when physical reaction is most needed.

Could prolonged exposure to high levels of adrenaline be a factor, too, in early and permanent cognitive decline?

–What are the physical and mental ramifications of  performance enhancement drugs that are widely consumed by elite athletes?

None of this is to minimize these latest brain studies nor to excuse the NFL actions or inactions to date. However, further research is required to learn why some persons suffer greater than average mental and physical debilitation during their lives regardless of their professions.