A new study from the University of Auckland has found that former high-level male rugby players in New Zealand are more likely to develop dementia, including Alzheimer’s disease, later in life.
According to the research, these former players had a 22 percent higher risk compared to men in the general population.
The study was conducted by Dr. Stephanie D’Souza from the COMPASS Research Centre and Dr. Ken Quarrie from New Zealand Rugby.
They looked at data from nearly 13,000 men who played provincial-level or higher rugby between 1950 and 2000.
Their health outcomes were compared to more than 2.4 million New Zealand men who did not play rugby at that level. All participants were matched based on age, ethnicity, and place of birth.
The researchers found that for every 1,000 men in the general population, about 52 were diagnosed with or died from a neurodegenerative disease over the 35-year follow-up period from 1988 to 2023.
Among the rugby players, however, the number was 65 per 1,000. That means there were 13 extra cases for every 1,000 players over time, or about four extra cases each year in the study group.
Both international/professional and provincial-level players showed an increased risk of disease, though the risk was higher for those who played at the international level.
Interestingly, players in backline positions (like fullbacks or wings) had higher risks than forwards (like props or locks). For backs, the risk went up the more years or matches they played—a pattern not seen in forwards.
The increased risk generally began to show around age 70. There was no evidence that these players developed dementia earlier than expected.
Dr. D’Souza said these results are similar to findings from studies of other collision sports in countries like the United States, Scotland, and Italy. However, the risk levels in this study were a bit lower than in previous research.
She explained this might be because the study included a wider range of rugby players—not just elite professionals—and used different methods for identifying dementia cases. Also, rugby in New Zealand has changed over the decades, which may affect long-term health outcomes.
This research is part of the Kumanu Tāngata project, which studies the health of former rugby players using anonymous linked data. The study adds to a growing body of evidence that suggests repeated head impacts in collision sports may raise the risk of brain disease later in life.
While this study cannot prove that rugby causes dementia, the clear pattern of increased risk among those who played longer and at higher levels makes the link stronger. The findings also suggest a possible “dose-response” relationship—meaning that more time or intensity in the sport may increase the chance of long-term brain issues.
The researchers believe that rugby organizations should take steps to reduce head impacts and manage concussions more carefully. They also recommend that the risks and benefits of playing sports like rugby be clearly communicated to players and the public.
This important study gives players, families, and sporting bodies more information to make informed decisions about safety in rugby and similar sports.
The study is published in Sports Medicine.
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