Examining later-in-life health risks associated with sport-related concussion and repetitive head impacts: a systematic review of case-control and cohort studies

Abstract

ObjectiveConcern exists about possible problems with later-in-life brain health, such as cognitive impairment, mental health problems and neurological diseases, in former athletes. We examined the future risk for adverse health effects associated with sport-related concussion, or exposure to repetitive head impacts, in former athletes.DesignSystematic review.Data sourcesSearch of MEDLINE, Embase, Cochrane, CINAHL Plus and SPORTDiscus in October 2019 and updated in March 2022.Eligibility criteriaStudies measuring future risk (cohort studies) or approximating that risk (case-control studies).ResultsTen studies of former amateur athletes and 18 studies of former professional athletes were included. No postmortem neuropathology studies or neuroimaging studies met criteria for inclusion. Depression was examined in five studies in former amateur athletes, none identifying an increased risk. Nine studies examined suicidality or suicide as a manner of death, and none found an association with increased risk. Some studies comparing professional athletes with the general population reported associations between sports participation and dementia or amyotrophic lateral sclerosis (ALS) as a cause of death. Most did not control for potential confounding factors (eg, genetic, demographic, health-related or environmental), were ecological in design and had high risk of bias.ConclusionEvidence does not support an increased risk of mental health or neurological diseases in former amateur athletes with exposure to repetitive head impacts. Some studies in former professional athletes suggest an increased risk of neurological disorders such as ALS and dementia; these findings need to be confirmed in higher quality studies with better control of confounding factors.PROSPERO registration numberCRD42022159486.

How to identify and manage sports related concussions in primary care

“…The patient should be made aware (and reassured) that CTE and associated symptoms tend to occur as a result of repetitive trauma, and not from a single concussive event. A systematic review on concussions in amateur athletes did not find an association between concussions and future risk of mental health issues and neurodegenerative disorders,34 but the authors recognise the need for further studies in this area, with improved control of confounding factors in the study population.…”

Chronic traumatic encephalopathy neuropathologic change in former Australian rugby players

“…It is not known if, or the extent to which, CTE-NC is the underlying cause or contributing underlying cause of specific clinical problems during life, especially psychiatric problems [5,18]. In a large-scale clinicopathological association study [19], there was no association between CTE-NC and depression, suicidality, anxiety, paranoia, apathy, impulsivity, explosivity, violence or motor symptoms or problems during life.…”

Kumanu Tāngata: the aftermatch study – protocol to examine the health outcomes of high-level male rugby union players using linked administrative data

“…In addition, postmortem examinations have revealed evidence of chronic traumatic encephalopathy neuropathological change (CTE-NC) in the brains of former athletes,3 4 with associations observed between CTE-NC and repetitive head impacts in contact sports 5. Although questions remain about the clinical significance of CTE-NC,6 these findings have led to increasing attention, both in scientific publications6–8 and in books and media reports,9 10 of the potential long-term impacts of mild TBI and repetitive head acceleration events resulting from exposure to contact sports.…”

“…Consequently, much of the research on health outcomes linked to participation in contact sports has focused on neurodegenerative diseases. Recent systematic reviews and meta-analyses have indicated an increased risk of neurodegenerative diseases and mortality attributed to neurodegenerative diseases, particularly in professional-level contact sport athletes 6–8 11. In studies using large-scale administrative data, higher mortality from neurodegenerative diseases has been reported in professional association football players12–15 and former National Football League athletes16 17 when compared with the general population.…”