The association between participation in high-impact contact sports and development of young-onset dementia: a narrative systematic review

Abstract Background There is growing concern that repetitive brain injury from high impact sports participation may be a risk factor for dementia, and brain injury has been linked to younger age of dementia onset. People with young-onset dementia often have unique needs and challenges, requiring support that is tailored to their age and interests; therefore, it is important for collision sporting worlds to have insight into whether young-onset dementia risk is an area of concern for their alumni. The aim of this review was to evaluate observational studies to ascertain the nature of association for young onset dementia and high impact contact sports in current empirical literature. Method Five databases were searched up to November 2025 with terms covering sports associated with concussion risk, including a wide variety of combat sports, team based high-impact and collision sports, and individual sports associated with high concussion risk, along with progressive neurodegenerative pathologies and as terminologies relating to concussion. Studies were eligible for inclusion if they included a measurement of a clinically diagnosable dementia in their samples and participants associated with a high impact contact sport. Analysis grouped studies based on comparability to young-onset dementia, either directly (group 1) or through a mean age below 65 (group 2). Due to heterogeneity of study methodology, a narrative synthesis was adopted to report the findings of the review. Results Eight studies were eligible for inclusion, consisting of 7,385 participants. Studies largely focused on soccer and American football, but cycling and ice-hockey were included in two studies. Most studies identified dementia through self-reporting ( n = 5), but telephone assessment alongside self-report ( n = 1), and assessment of medical and death records ( n = 2) were also utilised. NFL (National Football League) players may be at an increased risk of developing dementia at younger ages compared to the general population. Findings on association football were suggestive of an increased risk of dementia for younger people; however, a sensitivity analysis suggested this evidence is not consistent. Conclusions Existing evidence on the impact of sport-related brain injury and young-onset dementia is very limited to date. The sport and dementia literature may not be reflective of the experiences of those aged below 65. Future research should place emphasis on the concern around athletes at a young age reporting dementia diagnosis, as well as considering additional sports, countries, and demographics.