In a groundbreaking new study conducted by researchers at the University of Auckland, compelling evidence has emerged linking participation in high-level rugby with an elevated risk of developing neurodegenerative diseases such as Alzheimer’s and other forms of dementia. This study, which focused specifically on former male rugby players from New Zealand who competed at the provincial level or higher between 1950 and 2000, reveals a 22 percent increase in the risk of these debilitating conditions later in life compared to the general male population. This research marks a significant step forward in understanding the long-term neurological consequences associated with collision sports, a topic that has garnered increasing global attention in recent years.
The research was spearheaded by senior lecturer Dr. Stephanie D’Souza from the University of Auckland’s COMPASS Research Centre, alongside Dr. Ken Quarrie from New Zealand Rugby. Together, they conducted an exhaustive comparison involving nearly 13,000 former rugby players matched against a control group of approximately 2.4 million New Zealand men. By carefully controlling for age, ethnicity, and birthplace, the study ensured robustness in its comparative analysis. This large-scale approach harnessed decades of data, shedding unprecedented light on the subtle yet impactful long-term neurological outcomes attributed to sustained exposure to rugby’s inherently physical nature.
The study’s data spanned a follow-up period from 1988 to 2023, allowing sufficient time to capture disease incidence across the aging population. Among the general population, 52 cases of neurodegenerative diseases per 1,000 individuals were recorded. However, in the former rugby cohort, this figure was notably higher, at 65 cases per 1,000. Lead author Francesca Anns, a PhD candidate contributing critical statistical analysis, highlighted the significance of this finding: “This increase equates to an additional 13 cases per 1,000 individuals over the study period, translating to approximately four extra cases annually, given the size of our cohort.” These statistics signify a measurable burden on the neurological health of those exposed to competitive rugby.
Intriguingly, the study revealed that increased risks were not uniform across all players but varied by playing level and position on the field. Both international and professional players experienced higher incidences of neurodegeneration than those who only played at provincial or amateur first-class levels. Moving beyond mere participation, the research highlighted positional nuances: players occupying backline positions were found to bear greater risk relative to forwards. Furthermore, for backs, the risk amplified with the length of their playing careers and the number of matches played, suggesting a dose-dependent relationship between cumulative exposure and disease manifestation.
This dose-response relationship – where risk increases with greater cumulative exposure – is particularly notable. It implies that repetitive head impacts, more prevalent or severe in certain positions and prolonged careers, could precipitate or exacerbate neurodegenerative pathways. Contrastingly, forwards did not exhibit this progressive risk trend, raising critical questions about the types of collisions encountered in different roles and their respective neurological consequences. These position-specific findings suggest that the biomechanical forces and contact nature intrinsic to rugby might play nuanced roles in long-term brain health outcomes.
Neuropathological effects of repetitive head trauma have been a subject of intense focus globally, especially in collision sports like football, boxing, and ice hockey. However, the current study’s results diverge slightly from previous international research regarding effect size. Dr. D’Souza posits that these differences may stem from methodological variances, such as study design, population size, and the inclusion criteria encompassing both provincial and international players, rather than exclusively elite professionals. Additionally, evolving gameplay styles in New Zealand rugby over the decades under consideration may have influenced exposure levels and risk magnitudes, underscoring the complexity of assessing long-term outcomes across varying historical contexts.
Notably, the increased incidence of neurodegenerative disease among former rugby players did not become apparent until later in life. The study found no evidence suggesting earlier onset of illness prior to age 70, indicating that neurodegenerative processes linked to rugby exposure manifest predominantly as late-life conditions. This delayed emergence emphasizes the necessity for longitudinal observation and underscores aging as a critical factor interacting with prior head trauma to influence disease development. The latency also presents challenges for early diagnosis and intervention in at-risk athletic populations.
These findings are situated within the broader context of the Kumanu Tāngata project, a comprehensive investigation into the long-term health outcomes of first-class rugby players in New Zealand. Utilizing de-identified, linked data from the Integrated Data Infrastructure (IDI), the project leverages a rich repository of anonymous microdata to maintain privacy while facilitating powerful epidemiological analyses. This approach allows for a meticulous, large-scale examination of health trajectories, thereby providing compelling evidence to support the observed associations between collision sports and neurodegenerative disease risk.
While causality cannot be definitively established through this research alone, the consistent pattern corroborated by this and other international studies lends increasing credibility to the connection between repetitive head trauma and later-life brain health deterioration. The study’s distinct observation of higher risks among those with the most intense and prolonged exposure, plus positional specificity in risk profiles, further strengthens the hypothesis of a direct mechanistic link rather than mere correlation.
The implications of these discoveries extend beyond academic interest, pressing collision sport governing bodies and health policymakers to re-evaluate safety protocols. The researchers advocate for proactive strategies that limit player exposure to head impacts, alongside rigorous management and monitoring of suspected concussions. Transparent communication about both the benefits and inherent risks of rugby participation is crucial to fostering informed decision-making among players, coaches, and medical teams alike. These measures could help mitigate future burdens of neurodegenerative diseases without compromising the cultural and physical significance of the sport.
Ultimately, this landmark study offers a sobering reminder of the hidden neurological costs that may accompany a celebrated athletic career in rugby. As the global scientific community continues to unravel the complex interplay between repetitive sports-related head trauma and neurodegeneration, such nuanced and extensive epidemiological research sets a new standard. The challenge now lies in translating these insights into effective preventative measures and therapeutic approaches to safeguard the brain health of current and future generations of rugby players worldwide.
Subject of Research: People
Article Title: Neurodegenerative Diseases in Male Former First-Class New Zealand Rugby Players
News Publication Date: 4-Sep-2025
Web References:
https://link.springer.com/article/10.1007/s40279-025-02299-y
References:
Anns, F., Quarrie, K.L., Milne, B.J., Li, C., Gardner, A.J., Murphy, I.R., Verhagen, E., Wright, C., Morton, S., Lumley, T., Tippett, L., & D’Souza, S. (2025). Neurodegenerative diseases in male former first-class New Zealand rugby players. Sports Medicine.
Image Credits: Not provided.
Keywords: Health and medicine, Diseases and disorders
