Knocking a person unconscious or even causing a concussion may cause permanent brain damage.[71] There is no clear division between the force required to knock a person out and the force likely to kill a person.[72] Additionally, contact sports, especially combat sports, are directly related to a brain disease called chronic traumatic encephalopathy, abbreviated as CTE. This disease begins to develop during the life of the athlete, and continues to develop even after sports activity has ceased.
In March 1981, neurosurgeon Fred Sonstein sought to use CAT scans in an attempt to track the degeneration of boxers' cognitive functions after seeing the decline of Bennie Briscoe.[73] From 1980 to 2007, more than 200 amateur boxers, professional boxers and Toughman fighters died due to ring or training injuries.[74] In 1983, editorials in the Journal of the American Medical Association called for a ban on boxing.[75] The editor, George Lundberg, called boxing an "obscenity" that "should not be sanctioned by any civilized society".[76] Since then, the British,[77] Canadian[78] and Australian[79] Medical Associations have called for bans on boxing.
Supporters of the ban state that boxing is the only sport where hurting the other athlete is the goal. Bill O'Neill, boxing spokesman for the British Medical Association, has supported the BMA's proposed ban on boxing: "It is the only sport where the intention is to inflict serious injury on your opponent, and we feel that we must have a total ban on boxing."[80] Opponents respond that such a position is misguided opinion, stating that amateur boxing is scored solely according to total connecting blows with no award for "injury". They observe that many skilled professional boxers have had rewarding careers without inflicting injury on opponents by accumulating scoring blows and avoiding punches winning rounds scored 10–9 by the 10-point must system, and they note that there are many other sports where concussions are much more prevalent.[citation needed] However, the data shows that the concussion rate in boxing is the highest of all contact sports.[81][82][83] In addition, repetitive and subconcussive blows to the head, and not just concussions, cause CTE,[84][85][86][87][88][89] and the evidence indicates that brain damage and the effects of CTE are more severe in boxing.[90][91][92][93][94][95]
In 2007, one study of amateur boxers showed that protective headgear did not prevent brain damage,[96] and another found that amateur boxers faced a high risk of brain damage.[97] The Gothenburg study analyzed temporary levels of neurofilament light in cerebral spinal fluid which they conclude is evidence of damage, even though the levels soon subside. More comprehensive studies of neurological function on larger samples performed by Johns Hopkins University in 1994 and accident rates analyzed by National Safety Council in 2017 show amateur boxing is a comparatively safe sport due to the regulations of amateur boxing and a greater control of the athletes,[98] although the studies did not focus on CTE or its long-term effects. In addition, a good training methodology and short career can reduce the effects of brain damage.[99]
In 1997, the American Association of Professional Ringside Physicians was established to create medical protocols through research and education to prevent injuries in boxing.[100][101]
Professional boxing is forbidden in Iceland,[102] Iran and North Korea. It was banned in Sweden until 2007 when the ban was lifted but strict restrictions, including four three-minute rounds for fights, were imposed.[103] Boxing was banned in Albania from 1965 until the fall of Communism in 1991. Norway legalized professional boxing in December 2014.[104]
The International Boxing Association (AIBA) restricted the use of head guards for senior males after 2013.[105][106] A literature review study analyses present knowledge about protecting headgear and injury prevention in boxing to determine if injury risks associated with not head guard usage increased. The research of the reviewed literature indicates that head guards cover well against lacerations and skull fractures. Therefore, AIBA's decision to terminate the head guard must be considered cautiously, and injury rates among (male) boxers should be continuously evaluated.