Friday, September 05, 2025

 

Deaths from high blood pressure-related kidney disease up nearly 50% in the past 25 years



American Heart Association

 





Research Highlights:

  • An analysis of 25 years of the CDC WONDER database for death rates from hypertension-related kidney disease (also called hypertensive kidney disease or hypertensive renal disease) in the U.S. through 2023 found persistent differences across race, ethnicity, gender and region.
  • The highest death rates for hypertensive kidney disease were among Black individuals, followed by Hispanic individuals.
  • More men died from hypertensive kidney disease than women, and states in the South had the highest death rates from hypertensive kidney disease.
  • These findings highlight the urgent need for improved screening and management of high blood pressure to reduce the risk of hypertensive kidney disease, especially in communities at higher risk.
  • Note: The study featured in this news release is a research abstract. Abstracts presented at the American Heart Associations scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

Embargoed until 5:30 p.m. ET/4:30 p.m. CT, Thursday, Sept. 4, 2025

BALTIMORE, Sept. 4, 2025 — The  death rate from hypertensive kidney disease (high blood pressure-related kidney disease) increased by 48% in the U.S. over the past 25 years, with continued differences across demographic groups, according to preliminary research presented at the American Heart Association’s Hypertension Scientific Sessions 2025. The meeting is in Baltimore, September 4-7, 2025, and is the premier scientific exchange focused on recent advances in basic and clinical research on high blood pressure and its relationship to cardiac and kidney disease, stroke, obesity and genetics.

“This is the first study to examine 25 years of national data on hypertensive kidney disease deaths across all U.S. states and major demographic groups,” said Joiven Nyongbella, M.D., an M.P.H. candidate and internal medicine resident at Wayne State University/Henry Ford Rochester Hospital in Detroit. “Despite national efforts to reduce health inequalities, Black individuals still had over three times the death rate compared to other groups of people.”

High blood pressure (when the force of the blood pushing against the walls of vessels is too high) is a known risk factor for kidney damage. It is the second leading cause of end-stage kidney disease and contributes significantly to morbidity and mortality. Untreated high blood pressure can lead to serious outcomes, such as heart attack, stroke, heart failure and progression to kidney failure. Globally, the rate of death from chronic kidney disease increased 24% from 1990 to 2021, according to the American Heart Association’s 2025 Heart Disease and Stroke Statistics.

This study, looking at data from 1999 – 2023, found age-adjusted mortality rate (AAMR) for hypertensive kidney disease deaths increased 48%. Men, people living in the South and Black  or Hispanic adults had higher than average death rates.

“High blood pressure isn’t just about strokes or heart attacks - it’s also a major cause of kidney disease and death, especially in Black and Hispanic communities,” said Nyongbella. “The message is simple: check your blood pressure, treat it early and don’t ignore it, because it can quietly lead to life-threatening kidney problems.”

In this study, researchers reviewed data from the U.S. Centers for Disease Control and Prevention’s (CDC’s) WONDER database from 1999 to 2023 for all death certificates noted with hypertensive renal disease as the cause of death. The analysis found:

  • Kidney disease caused by high blood pressure resulted in 274,667 deaths from 1999-2023 among individuals ages 15 and older.
  • From 1999-2023, the age-adjusted mortality rate (AAMR) for hypertensive kidney disease deaths rose from 3.3 per 100,000 people in 1999 to 4.91 per 100,000 people in 2023, an increase of 48%.
  • Men had a higher average AAMR than women (4.48 vs. 3.69, respectively), with a 22% higher mortality in individuals with renal failure.
  • The highest average AAMR was for individuals who were identified as Black, at 10.37 per 100,000 people versus the range of 3.33 - 3.90 per 100,000 for people in other population groups. Hispanic individuals had a 15% higher AAMR when compared to non-Hispanic individuals (4.55 vs. 3.97, respectively).
  • Across the U.S., the West had the highest overall AAMR for hypertensive kidney disease deaths at 4.59 per 100,000. In the South, Washington, D.C., (7.6 per 100,000), Tennessee (5.9) and Mississippi (5.83) had the highest AAMRs.

“This study provides important observational data indicating a concerning rise (48%) in age-adjusted deaths due to high blood pressure-related kidney disease over the last 25 years, especially among men, and Black and Hispanic individuals,” said American Heart Association volunteer expert Sidney C. Smith Jr., M.D., FAHA. “These findings are in line with the recently released 2025 AHA/ACC High Blood Pressure Guideline and AHA’s Presidential Advisory on Cardiovascular Kidney Metabolic (CKM) Health. Both papers emphasize the importance of early treatment for high blood pressure, its direct link to kidney disease, as well as the impact of social factors among high-risk populations.” Smith is a cardiologist and professor of medicine at the University of North Carolina’s School of Medicine, a past president of the American Heart Association and a co-author of the 2025 AHA/ACC High Blood Pressure Guideline; he was not involved in this study.

There are several limitations to the study’s findings. Of note, the study relied solely on death certificate data, which may include errors due to missing or mislabeled causes of death. In addition, individual health factors like access to care, medication use or diet were not available, so future research is needed to investigate these factors in addition to health data.

Study details, background and design:   

  • Data from the CDC WONDER database was reviewed for all death certificates in the U.S. from 1999 to 2023 with any of the ICD-10 codes for hypertensive renal disease with and without renal failure listed as a cause of death.
  • The analysis included demographic information about people who had died with and without hypertensive renal disease, ages 15 to 85 and older; 54.9% were women, 23.5% were Black, 8.47% were Hispanic and 68% were from other racial and ethnic groups.
  • Age-adjusted mortality rates (AAMRs) per 100,000 were calculated and stratified by year, sex, race, ethnicity, state and region.
  • The abstract also details the additional calculations used to assess trends including average annual percent change (AAPC) in deaths statistical testing.

Note: Poster Presentation #FR524 will be presented during Poster Session 2, 9:00 a.m. – 10:30 a.m. ET, Friday, Sept. 5, 2025.

Co-authors, their disclosures and funding sources are listed in the abstract.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

The Association receives more than 85% of its revenue from sources other than corporations. These sources include contributions from individuals, foundations and estates, as well as investment earnings and revenue from the sale of our educational materials. Corporations (including pharmaceutical, device manufacturers and other companies) also make donations to the Association. The Association has strict policies to prevent any donations from influencing its science content and policy positions. Overall financial information is available here.

Additional Resources:

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U.S. survey finds salt substitutes rarely used by people with high blood pressure




American Heart Association





Research Highlights:

  • Despite their effectiveness in lowering sodium intake and managing blood pressure, salt substitutes were rarely used by people with high blood pressure, according to a review of almost 20 years of U.S. health survey data.
  • Researchers recommend increasing awareness of salt substitutes as a strategy to help effectively treat blood pressure, especially for individuals with difficult-to-treat or treatment-resistant high blood pressure.
  • Note: The study featured in this news release is a research abstract. Abstracts presented at American Heart Associations scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

Embargoed until 5:30 p.m. ET/4:30 p.m. CT, Thursday, Sept. 4, 2025

BALTIMORE, Sept. 4, 2025 — Few people with high blood pressure were using salt substitutes, even though they are a simple and effective way to lower sodium intake and manage blood pressure, according to preliminary research presented at the American Heart Association’s Hypertension Scientific Sessions 2025. The meeting is in Baltimore, September 4-7, 2025, and is the premier scientific exchange focused on recent advances in basic and clinical research on high blood pressure and its relationship to cardiac and kidney disease, stroke, obesity and genetics.

High blood pressure occurs when the force of blood flowing through the blood vessels is consistently too high. High blood pressure can lead to other serious events such as heart attack and stroke. Using data from 2017 to 2020, 122.4 million (46.7%) adults in the U.S. had high blood pressure  and it contributed to more than 130,000 deaths. Too much sodium and too little potassium in the diet are risk factors for high blood pressure.

“Overall, less than 6% of all U.S. adults use salt substitutes, even though they are inexpensive and can be an effective strategy to help people control blood pressure, especially people with difficult-to-treat high blood pressure,” said lead study author Yinying Wei, M.C.N., R.D.N., L.D., and Ph.D. candidate in the departments of applied clinical research and hypertension section, cardiology division, at UT Southwestern Medical Center in Dallas. “Health care professionals can raise awareness about the safe use of salt substitutes by having conversations with their patients who have persistent or hard-to-manage high blood pressure.”

Salt substitutes are products that replace some or all of the sodium with potassium. Potassium salt tastes similar to regular salt, except when heated it can have a bitter aftertaste. Many foods contain some sodium in their natural state, however, the largest amount of sodium comes from processed and packaged foods and meals prepared at restaurants. The American Heart Association recommends consuming no more than 2,300 mg of sodium a day, with an ideal limit of less than 1,500 mg per day for most adults, especially for those with high blood pressure. For most people, cutting back by 1,000 mg a day can improve blood pressure and heart health.                                                

This study is the first to examine long-term trends in salt substitute use among a nationally representative sample of U.S. adults. Using data from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2020, researchers analyzed the use of products that replace salt with potassium-enriched or other alternative salts.

The investigation focused on people with high blood pressure, and an additional analysis was conducted among adults eligible to use salt substitutes, including people with normal kidney function and those not taking medications or supplements that affect blood potassium levels. Some salt substitutes contain potassium, and they can raise blood potassium to dangerous levels in people with kidney disease or those taking certain medications or potassium supplements. Excessive potassium can lead to irregular heart rhythms.  People with high blood pressure who are thinking about switching from regular salt to a salt substitute should first consult with a health care professional.

The analysis found:

  • Overall, salt substitute use among all U.S. adults remained low, peaking at 5.4% in 2013–2014 before falling to 2.5% by 2017–March 2020. Data collection for 2020 stopped before March because of the pandemic.
  • Among adults eligible to use salt substitutes, only 2.3% to 5.1% did so.
  • Usage was highest in people with high blood pressure whose BP was controlled with medications (3.6%–10.5%), followed by those with high blood pressure whose BP was not controlled despite medications (3.7%–7.4%).
  • Salt substitute use remained consistently less than 5.6% among people with untreated high blood pressure and for people with normal blood pressure.
  • Adults who ate at restaurants three or more times a week appeared less likely to use salt substitutes compared to those who ate out less often, but this difference was no longer statistically significant after accounting for age, race/ethnicity, education level and insurance status.

“Salt substitute use remained uncommon over the last two decades including among people with high blood pressure,” Wei said. “Even among individuals with treated and poorly managed or untreated high blood pressure, most continued to use regular salt.”

“This study highlights an important and easy missed opportunity to improve blood pressure in the U.S.—the use of salt substitutes,” said Amit Khera, M.D., M.Sc., FAHA, an American Heart Association volunteer expert. “The fact that use of salt substitutes remains so low and has not improved in two decades is eye-opening and reminds patients and health care professionals to discuss the use of these substitutes, particularly in visits focused on high blood pressure.” Khera, who was not involved in this study, is a professor of medicine, clinical chief of cardiology and director of preventive cardiology at UT Southwestern Medical Center in Dallas.

The study has several limitations. First, information about salt substitute use was self-reported, so there may have been underreporting or misclassification. In addition, all types of salt substitutes were included in the analysis, therefore, the analysis could not specifically separate potassium-enriched salt from other types of salt substitutes. Finally, the survey data did not capture how much salt substitute the participants used.

“Future research should explore why salt substitute-use remains low by investigating potential barriers, such as taste acceptance, cost and limited awareness among both patients and clinicians,” said Wei. “These insights may help guide more targeted interventions.”

Study details, background and design:   

  • The analysis included 37,080 adults, ages 18 and older (37.9% were aged 18–39, 36.9% were aged 40–59 years, and 25.2% were aged 60 and older). 50.6% of participants were women, 10.7% of participants self-reported their race as non-Hispanic Black, and 89.3% self-reported they were from other racial and ethnic groups.
  • Participants were categorized into four subgroups based on presence or absence of high blood pressure (≥130/80 mm Hg) and whether they were using blood pressure lowering medication: 1) high blood pressure that was treated and controlled; 2) high blood pressure that was treated and not controlled; 3) untreated high blood pressure; and 4) those with normal blood pressure.
  • Salt types were classified as ordinary salt (iodized salt, sea salt, kosher salt), salt substitute (potassium-enriched or other salt substitute) and no salt use.
  • An additional analysis was conducted on a subgroup of individuals eligible to use salt substitutes—those with healthy kidney function (estimated glomerular filtration rate ≥ 60) and not taking medications or supplements that affect blood potassium levels. 
  • The frequency of eating at restaurants to assess its influence on salt substitute use was also evaluated.
  • All analyses incorporated NHANES sampling weights and complex survey design.

Note: Poster Presentation #TAC228 will be presented during Poster Session 1, 5:30 p.m. - 7:00 p.m. ET, Thursday, Sept. 4, 2025.

Co-authors, their disclosures and funding sources are listed in the abstract. The study is supported by a grant from the National Institutes of Health.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal. 

The Association receives more than 85% of its revenue from sources other than corporations. These sources include contributions from individuals, foundations and estates, as well as investment earnings and revenue from the sale of our educational materials. Corporations (including pharmaceutical, device manufacturers and other companies) also make donations to the Association. The Association has strict policies to prevent any donations from influencing its science content and policy positions. Overall financial information is available here.

Additional Resources:

###

The American Heart Association’s Hypertension Scientific Sessions 2025 is a premier scientific conference dedicated to recent advancements in both basic and clinical research related to high blood pressure and its connections to cardiac and kidney diseases, stroke, obesity and genetics. The primary aim of the meeting is to bring together interdisciplinary researchers from around the globe and facilitate engagement with leading experts in the field of hypertension. Attendees will have the opportunity to discover the latest research findings and build lasting relationships with researchers and clinicians across various disciplines and career stages. Follow the conference on X using the hashtag #Hypertension25.

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. Dedicated to ensuring equitable health in all communities, the organization has been a leading source of health information for more than one hundred years. Supported by more than 35 million volunteers globally, we fund groundbreaking research, advocate for the public’s health, and provide critical resources to save and improve lives affected by cardiovascular disease and stroke. By driving breakthroughs and implementing proven solutions in science, policy, and care, we work tirelessly to advance health and transform lives every day. Connect with us on heart.orgFacebookX or by calling 1-800-AHA-USA1.


Thursday, September 04, 2025

 

Can courts safeguard fairness in an AI age?



Santa Fe Institute






In the criminal justice system, decisions about when and how long to detain people have historically been made by other people, like judges and parole boards. But that process is changing: Decision-makers increasingly include artificial intelligence systems in a variety of tasks, from predicting crime to analyzing DNA to recommending prison sentences. The use of AI in these domains raises pressing questions about how these computing systems use data to make predictions and recommendations, as well as larger questions about how to safeguard fairness in an AI age. 

Notably, many AI systems are “black boxes,” which means their behavior and decision-making processes are opaque to scrutiny. This poses a problem in the justice system, in which public trust and the accountability of key players like judges are tied to an understanding of how and why life-changing decisions are made. In addition, even if a black box system is statistically fair and accurate, it may not meet standards of procedural fairness required by our constitutional system.

In April 2024, the National Institute of Justice (NIJ) issued a public request for information that could help inform future guidelines on safe and effective ways to use AI in the criminal justice system. The Computing Research Association — a large organization focused on innovative computing research related to timely challenges — responded by convening a team of experts from academic institutions and industry to crystallize a comment to submit to the NIJ. SFI Professor Cris Moore and External Professor Stephanie Forrest (Arizona State University) were among the submission’s authors. The group’s argument was clear: Where constitutional rights are at stake, critical decisions shouldn’t be made using AI with hidden processes.

“The idea that an opaque system — which neither defendants, nor their attorneys, nor their judges understand — could play a role in major decisions about a person’s liberty is repugnant to our individualized justice system,” the authors noted. “An opaque system is an accuser the defendant cannot face; a witness they cannot cross-examine, presenting evidence they cannot contest.” 

This August, the group followed up with an opinion published in the Communications of the ACM. While the original Executive Order 14110 that prompted the NIJ’s query has been rescinded, a new Executive Order 13859 calls for safe testing of AI and to “foster public trust and confidence in AI technologies and protect civil liberties, privacy, and American values in their application.”

In a criminal-justice setting, AI technologies would only fit this bill if they improve both the fairness and transparency of the current system, says Moore. This is part of what makes AI appealing. Human decision-making processes, after all, aren’t always transparent either. 

“We should use AI if it makes the judicial system more transparent and accountable,” Moore says. “If it doesn’t, we shouldn’t use it.”

He and his collaborators submitted their remarks to the NIJ in May, 2024. They highlighted key arguments that the Justice Department should consider as it develops and implements new guidelines about the fair and beneficial use of AI in sentencing and other cases. Many of those arguments emphasized the need for transparency: everyone who either uses AI or is affected by an AI-produced recommendation should have a clear understanding of the data it used, and how it came up with its recommendations or risk scores. In addition, the experts advised, the procedure by which a judge uses guidance from an AI system should be clear. 

Some researchers have warned that increasing transparency can reduce the usefulness of an AI system, but in the last few years, researchers in the field of “explainable AI” have developed approaches that help illuminate how these models process information and produce inputs. 

Explainable AI systems may help, but Moore notes that there is a range of ways to define transparency. Transparency doesn’t have to mean that everyone understands the computer code and mathematics under the hood of a neural network. It could mean understanding what data were used, and how. He points to the Fair Credit Reporting Act (FCRA), which requires credit-rating companies to disclose consumer information used to make credit decisions and set ratings. The companies can keep their process hidden, says Moore, but a consumer can easily download the information used in the algorithm. It also gives consumers the right to contest those data if they’re not accurate. On the other hand, he points out that the FCRA doesn’t let consumers question whether the algorithm is doing the right thing with their data. “It’s important to be able to look at an AI’s inner workings, not just its inputs and outputs,” he says.

In addition to recommendations about transparency, the researchers advised that output from AI systems should be specific and quantitative — reporting a “7% probability of rearrest for a violent felony,” for example, rather than describing a suspect with a label like “high risk.” Qualitative labels, Moore says, leave too much room for misinterpretation. 

“If the judge understands what the system’s output means, including what kinds of mistakes they can make, then I think they can be useful tools,” Moore says. “Not as replacements for judges, but to provide an average or baseline recommendation.”  

Critically, the authors warned that AI systems should never completely replace human decision-makers, especially in cases where detention and the constitutional rights of a person are at stake. In the optimal scenario, AI systems might become a kind of digital consultant that produces output taken into consideration by a judge or other decision-maker, along with other factors related to the case. “But we should always be prepared to explain an AI’s recommendation, and to question how it was produced,” says Moore. 

 

Less than half of England has access to Mounjaro on the NHS months after roll-out



Over 200,000 patients may be eligible for treatment in the first three years, but some commissioners are already considering tighter prescribing criteria or rationing Figures confirm the fear that the roll out is not fit for purpose, says expert



BMJ Group






Less than half of England has access to tirzepatide (Mounjaro) through their GP, despite the NHS roll-out of the weight-loss jab officially starting over two months ago, an investigation by The BMJ has found.

Due to the large number of people who could benefit from tirzepatide - an estimated 3.4 million people - and the drug’s price, NHS England and its spending watchdog, the National Institute for Health and Care Excellence, agreed the injections would be rolled out in phases over a 12-year period, which commenced on 23 June 2025, explains Elisabeth Mahase. Yet just 18 out of 42 commissioning bodies (43%) across the country confirmed that they have started prescribing tirzepatide in line with this roll-out plan.

The data, obtained through Freedom of Information requests, also shows that despite NHS England stating that it expects 70% of eligible patients to come forward for treatment, just nine Integrated Care Boards (ICBs) - responsible for planning health services for their local population - confirmed they have been allocated enough NHS funding to cover at least 70% of their eligible patients.

Experts are warning that the lack of funding and poor communication to the public about the roll-out are driving “distress and uncertainty both in patients and primary care” and have left ICBs in a difficult financial situation.

Of the 40 ICBs that responded to The BMJ’s request, four reported that the NHS funding they had received covers just 25% or less of their eligible patients, with Coventry and Warwickshire faring the worst at 21% of its patients.

And five ICBs have said they are already considering further tightening the tirzepatide prescribing criteria or rationing the treatment beyond this 12-year phased plan.

Birmingham and Solihull ICB says it received funding to cover just 52% of its eligible patients, and said: “Difficult decisions are having to be made to ensure money is spent in the most effective and efficient way possible and for the greatest patient benefit.”

In London just one out of the five ICBs - South West London - has started prescribing tirzepatide, while notices urging patients not to contact their GP as they cannot provide these drugs have been posted by practices around the country, including in Suffolk and North East Essex - where funding for just 25% of eligible patients has been provided.

Tamara Hibbert, chair of Newham Local Medical Committee, says: “While there is significant potential for these drugs to benefit patients, the messaging needs to be clear about what they can expect in terms of the criteria for accessing them on the NHS and the funding available at an ICB level.”

Ellen Welch, Doctors' Association UK (DAUK) co-chair, says: “These figures confirm the fear that the roll out is not fit for purpose. There is a huge discrepancy between national messaging and what patients are actually being delivered on a local level.”

Others warn that the underfunding will have a knock-on effect for the following years, especially as more people will become eligible each year.

Jonathan Hazlehurst at the University of Birmingham, says: “NHS England is talking about treating 220,000 patients in the first three years, but we can see that the initial funding for year one clearly only covers approximately 10% of that.” He also warns that there are patients who would “benefit from really urgent and immediate treatment” with tirzepatide, but are not currently considered a priority.

Nicola Heslehurst, president of the Association for the Study of Obesity, says the deficit in funding compared with need “is another blow for people living with obesity who deserve evidence-based care to manage their health needs,” adding that the current commissioning model has set up a “postcode lottery” of who can access obesity care.

The BMJ contacted NHS England for comment, but received no response at the time of publication.

 

Study establishes link between rugby and dementia



University of Auckland researchers link high-level rugby to dementia




University of Auckland





Former male high-level rugby players in New Zealand have a 22 percent increased risk of developing Alzheimer’s and other dementias later in life compared to men in the general population, according to new research from the University of Auckland.

The project is co-led by senior lecturer Dr Stephanie D’Souza from the COMPASS Research Centre in the University’s Faculty of Arts and Education and Dr Ken Quarrie from New Zealand Rugby.

Researchers examined long-term neurodegenerative disease risk outcomes for almost 13,000 men who played provincial-level or higher rugby between 1950 and 2000 and compared them with 2.4 million New Zealand men, matched on age, ethnicity and birthplace.

Out of every 1,000 men in the general population, 52 died from, or were diagnosed with, a neurodegenerative disease over the follow-up period from 1988 to 2023, but among former rugby players, the number was 65 per 100, says the study’s lead author, PhD student Francesca Anns.

“This is an extra 13 cases per 1,000 people over the study period, or around four extra neurodegenerative disease cases per year, given the size of the player cohort,” she says.

And she says both international/professional and provincial/first-class amateur players had higher risks than the general population, although the risks were greater at the higher playing level.

“Our analysis also showed that players in backline positions had greater risks than forwards, with the risk for backs increasing further the longer they played or the more matches they played, a pattern not observed for forwards.”

Anns says the increased risk of disease typically became apparent from the age of 70 onwards, with no evidence of earlier-onset illness.

Co-lead investigator Dr Stephanie D’Souza says these results are consistent with research into other collision sports from the US, Scotland and Italy, but the effect sizes in their study were slightly smaller than most previous reports.

“That may reflect differences in how the study was designed,” she says, “including the size and make up of our comparison group, the fact that our study included both provincial and international players, rather than only elite professionals, and how cases were identified, as well as differences in how rugby was played in New Zealand over the decades we studied.”

The study is part of the Kumanu Tāngata project, which is focused on investigating the long-term health outcomes of first-class rugby players using de-identified linked data, which mean names are removed.

It adds to growing evidence linking collision sports with later-life brain health risks, believed to be due to exposure to head knocks, says D’Souza.

“While the research can’t prove causation, the consistent pattern across multiple studies strengthens the case for a connection. In this study, higher risks were seen in players who competed at the international or professional level, as compared to those who only played provincially, and for backs whose risk increased with more years and matches played.”

She says these patterns showing higher risk with both greater intensity and longer duration of play suggest a possible ‘dose-response’ relationship.

“The position differences also indicate that the nature of contact, not just the number of head impacts, may be important in understanding risk.”

The study’s authors recommend that collision sports organisations limit player exposure to head impacts and manage suspected concussions proactively, while continuing to communicate openly about both the benefits and risks of participation in sports like rugby.

Neurodegenerative diseases in male former first-class New Zealand rugby players by Francesca Anns, Kenneth L. Quarrie, Barry J. Milne, Chao Li, Andrew J. Gardner, Ian R. Murphy, Evert Verhagen, Craig Wright, Susan Morton, Thomas Lumley, Lynette Tippett and Stephanie D’Souza has been published in Sports Medicine.

This study was supported by World Rugby Limited and the New Zealand Rugby Foundation. Statistics New Zealand, and its staff granted researchers access to the Integrated Data Infrastructure (IDI), a large research database which holds anonymous microdata about people and households in New Zealand.

The Public Policy Institute at the University of Auckland granted access to its Statistics New Zealand data lab. The funders had no role in the study design, data collection, analysis, interpretation, or writing of the manuscript.