Rugby Linked to Higher Dementia Risk: New Zealand Study Reveals the Numbers

A new study from the University of Auckland has shed light on the long-term brain health risks associated with playing rugby at a high level. Researchers have found that men who played provincial or higher-level rugby in New Zealand between 1950 and 2000 face a 22% higher risk of developing Alzheimer’s disease or other dementias later in life compared to men in the general population.

Study Details and Scope

The research team analyzed health records of 12,861 male rugby players and compared them to a control group of about 2.39 million New Zealand men of the same age, ethnicity, and birthplace. The outcomes were tracked over a 35-year follow-up period, from January 1988 to June 2023. Mortality and hospitalization records were used to monitor neurodegenerative conditions in both groups.

The study was part of the Kumanu Tāngata project, which focuses on the long-term health of first-class rugby players using de-identified linked data from New Zealand’s Integrated Data Infrastructure (IDI).

Key Results

Across the follow-up period, around 52 men per 1,000 in the general population were diagnosed with or died from a neurodegenerative condition. Among rugby players, the number was 65 per 1,000. This translates to an extra 13 cases per 1,000 players, which equals roughly four additional cases per year within the player cohort.

The increased risks were clearly measurable:

• Any neurodegenerative disease: Hazard Ratio (HR) 1.22 (22% higher risk)
• Alzheimer’s disease: HR 1.61 (61% higher risk)
• Other dementias: HR 1.23 (23% higher risk)
• Parkinson’s disease: HR 1.05 (not statistically significant)
• Motor neuron disease: HR 1.16 (not statistically significant)

These findings confirm that rugby players were more likely to develop Alzheimer’s and other dementias, while conditions like Parkinson’s and motor neuron disease did not show a clear increase in risk.

Who Was Most at Risk?

The elevated risk of dementia typically appeared from age 70 onwards, with no evidence of earlier-onset illness. The study also highlighted key differences based on player position and career length:

• Backline players had greater risks than forwards.
• Players with longer rugby careers (six years or more) faced a 31% higher risk of any neurodegenerative disease and a 78% higher risk of Alzheimer’s disease.
• Players with 21 or more matches were more likely to develop a range of neurodegenerative diseases, including dementia and motor neuron disease.

These patterns suggest a dose–response relationship, meaning the longer and more intensely someone played, the greater the risk. The researchers also noted that the nature of head impacts may vary by position, which could explain why backs faced higher risks than forwards despite forwards being involved in frequent collisions.

Broader Context and Comparisons

This study adds to a growing body of evidence linking collision sports with later-life brain health risks. Similar research from the United States, Scotland, and Italy has reported comparable outcomes, though the effect sizes in this New Zealand study were slightly smaller. The differences may stem from how rugby was played in New Zealand over the decades, the inclusion of both provincial and international players, and the methodology used to identify cases.

Notably, this research comes in the context of broader awareness of rugby-related brain injuries. In 2024, Billy Guyton, a former professional rugby player, became the first in New Zealand to be posthumously confirmed with chronic traumatic encephalopathy (CTE) at just 33 years old, after repeated concussions ended his career. And in 2025, World Rugby’s Brain Health Service reported that a quarter of former elite players it assessed were at risk of cognitive issues.

Implications for Rugby and Player Safety

The University of Auckland researchers emphasized that while the study cannot conclusively prove causation, the consistent evidence across multiple studies makes the connection stronger. The fact that risks were higher for players with longer careers and more matches reinforces the importance of addressing exposure levels.

The authors recommend that collision sports organizations should:

• Limit player exposure to repeated head impacts.
• Manage concussions proactively when they occur.
• Communicate openly about both the benefits and risks of participation in sports like rugby.

They also stressed that the differences by position and career duration highlight how both intensity and duration of exposure matter in assessing risk.

Conclusion

This research provides strong, data-backed evidence that playing rugby at a high level increases the risk of Alzheimer’s and other dementias. With 22% higher overall risk, and even greater increases for players with long careers or backline roles, the findings underline the importance of safety measures, monitoring, and continued transparency from rugby organizations.

TLDR
A University of Auckland study of nearly 13,000 former rugby players found a 22% higher risk of dementia, especially Alzheimer’s, compared with the general population. Risks were greater for backs, long careers, and many matches, underscoring head-impact concerns in rugby.

Research Paper: Neurodegenerative Diseases in Male Former First-Class New Zealand Rugby Players (Sports Medicine, 2025)