Traumatic Brain Injuries (TBIs) are strongly suspected as being linked with the development of early onset dementia. This has implications for those who participate in combative sports (e.g. rugby, boxing etc.).
However, biological mechanisms which lead to dementia due to repeated minor brain injuries (e.g. as a result of 'headers' in soccer) have not yet been identified.
There remains no universally accepted neurobiological mechanism to explain the transition from acute TBI to the chronic effects of dementia. Studies of specialty populations, including athletes and military personnel are beset by secular and cohort effects, raising questions about the applicability of findings to the general population. No existing studies have been able to exclude the possible effects of confounding medical or lifestyle factors in facilitating the onset of dementia following TBI. Although the research findings suggest a general association between TBI and dementia, the specifics of the relationship remain poorly defined.
Source: Archives of Clinical Neuropsychology, Volume 35, Issue 2, March 2020, Pages 128–132