Are men who played high school football in Minnesota in the twenty-five years after World War II at increased risk of later developing dementia, Parkinson's or ALS compared with non-football playing high school males? Not according to two studies by researchers at the Mayo Clinic.
The first, published in 2012, compared the incidence of dementia, PD and ALS in 438 high school football players from Rochester, Minnesota who played the sport from 1946 to 1956 and 140 non-football playing male classmates. Researchers found that the football players were not at increased risk of later developing those neurodegenerative diseases.
The results were consistent with those of a 1990 study of individuals with Alzheimer's disease which also found no association between risk of disease and participation in contact sports, although, as noted in a 2013 paper, that study was limited by a small sample size.
In the second, published in 2017, researchers, using the same methodology as in the earlier study, extended their investigation to another group of varsity high school players from the next era, 1956 to 1970, a time when the rules, regulations, equipment, and physical ability of the football players was evolving to mirror more closely those of the present era, but a time in which football-related concussions were still often minimized or dismissed as "getting your bell rung."
Again, they found that individuals who played high school football between 1956 and 1970 did not have an overall increased risk of neurodegenerative outcomes or individual risks of dementia/mild cognitive impairment, parkinsonism, or ALS compared with their non-football playing classmates, this despite there being significantly more medically documented head trauma in football players.
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The Mayo Clinic researchers were careful to note in the two studies the many differences between today's high school football players and those who played in earlier eras: while today's players have better equipment, trainers and physicians who are more knowledgeable about concussions, play under rules which prohibit - at least in theory - leading with the head when blocking and tackling (spearing), and may be marginally more likely to report concussive symptoms than players from the two earlier eras, they also tend to be larger and quicker, increasing the force of impact, and wear helmets which, which, while "dramatically different from the marginally protective headgear of the earlier era, do not eliminate concussions and may give them a false sense of protection."
As a consequence, they cautioned that the results of the two studies should not be interpreted as evidence that football-related head trauma is benign. "The literature on chronic traumatic encephalopathy in college and professional football players," said the authors of the second study, "seems irrefutable," but there may be a "gradient of risk, with low potential in high school players."
Savica R, Parisi JE, Wold LE, Josephs KA, Ahlskog JE. High School Football and Risk of Neurodegeneration: A Community-Based Study. Mayo Clin Proc2012;87(14):335-340.
Pieter HHJ, Mandrekar J, Mielke MM, Ahlskog JE, Boeve BF, Josephs K, Savica R. High School Football and Late-Life Risk of Neurodegenerative Syndromes, 1956-1970. Mayo Clin Proc 2017;92(1):66-71.
Jordan BD, et al. Head trauma and participation in contact sports as risk factors for Alzheimer's disease. Neurology1990;40:347.
Jordan BD. The clinical spectrum of sport-related traumatic brain injury. Nat Rev Neurol2013;9:227-30.
