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A study published in Nature looks at the prevalence of Alzheimer’s Disease pathology in the community.
Prof Roslyn Bill, Professor of Biotechnology, Aston University, said:
“There is an urgent need for robust blood-based diagnostic markers that can be used to stratify patients with neurodegeneration. This study uses a large population to take a first step towards that goal. Further studies are needed to validate the authors’ findings. In the long term, blood tests like the one being used here should mean that patients can be treated with bespoke therapies most likely to delay the devastating effects of dementia and other consequences of neurodegeneration.”
Prof Louise Serpell, Emerita Professor of Biochemistry, University of Sussex, said:
“The study utilises the Alzheimer’s disease marker, Tau p217, which is a recent advance in diagnostics. This has allowed an analysis of a Norwegian cohort and provides some interesting and some surprising results.
“Importantly, the HUNT study includes a cognitive assessment for those over 70 for the diagnosis of Mild Cognitive impairment (MCI) or “Dementia”; while the specific diagnosis of Alzheimer’s disease is unclear. The use of the word Dementia is vague and does not clearly highlight those with Alzheimer’s disease. The Montreal cognitive assessment was used in the HUNT study and this detects cognitive impairment in general.
“Dementia is a general term that includes many different neurodegenerative diseases which include Alzheimer’s, dementia in Parkinson’s, as well as other causes.
“Alzheimer’s disease is defined by the deposition of Amyloid beta in amyloid plaques and tau in neurofibrillary tangles in the brain. Previously, this has been only confirmed at post-mortem. Early diagnosis is becoming more and more important to allow strategic therapy to be used to treat specific neurodegenerative diseases.”
David Thomas, Head of Policy and Public Affairs at Alzheimer’s Research UK, said:
“High quality studies like this are crucial to enhancing our understanding of how blood tests for Alzheimer’s could be used in clinical practice. These tests have huge potential in supporting an early and accurate dementia diagnosis. They are less invasive, relatively inexpensive and more scalable than existing tests that detect the biological signs of Alzheimer’s diseases, such as PET scans and spinal fluid sampling.
“However, the detection of the proteins linked with Alzheimer’s disease is not in itself a diagnosis. Some people will develop these proteins but never go on to experience the symptoms of the disease. Therefore, it’s important to interpret these findings with caution. Blood test results can also be less sensitive in older adults and future studies should address this by testing across a wider range of ages.
“We need to generate more evidence so we can use these tests in the NHS. Alzheimer’s Research UK and other partners are funding the READ-OUT and ADAPT studies of blood tests to develop these insights. Alzheimer’s Research UK is calling for the government to invest in the NHS services which provide dementia diagnosis in order to pave the way for new innovations in clinical practice.”
Prof Masud Husain, Professor of Neurology, University of Oxford, said:
“The findings are a potential gamechanger for screening for Alzheimer’s disease with a simple blood test combined with an assessment of cognitive function.”
“This is a very well conducted study with a large sample size. It combines good clinical assessment of cognition with the p-tau 217 blood test and provides a practical means of detecting early cognitive decline related to Alzheimer-related pathology, as well as from non-Alzheimer pathology.”
Prof Tara Spires-Jones, Director of the Centre for Discovery Brain Sciences at the University of Edinburgh, Division Lead in the UK Dementia Research Institute, and Past President of the British Neuroscience Association said:
“This is an interesting and important scientific study, adding to data indicating that Alzheimer’s disease prevalence is rising as our population ages. However, the top line of the press release “Dementia more prevalent in older people than previously thought” is exaggerated. This study looked at how commonly people had Alzheimer’s disease related changes and dementia symptoms across age groups in over 11,000 people in Norway. They found that around 60% of people over age 85 had Alzheimer’s-related biomarker changes similar to a large review of data from around the world published in 2023 which found 55-59% of people over age 85 exhibited these changes (ref 1). In the current study from Norway, scientists observed around 25% of people 85-89 years of age had dementia. Data from the Alzheimer’s association in 2025 indicate that over 30% of people over age 85 have Alzheimer’s disease (ref 2), meaning these new data are not a surprise. The strength of the current study is that scientists looked at a large group of people in a “population based study” meaning the data are highly representative of the Norwegian population. They also used strong clinical assessment of dementia symptoms and a highly accurate biomarker in blood tests. Limitations of the study include the relatively homogenous population in Norway with few people from diverse genetic backgrounds, which is important because Alzheimer’s disease prevalence is known to be different in people from different ethnicities.”
References for further info:
‘Prevalence of Alzheimer’s Disease Pathology in the Community – The HUNT Study’ by Dag Aarsland et al. was published in Nature at 16:00 UK time on Wednesday 17th December.
Declared interests
Prof Roslyn Bill: Roslyn Bill is a founder and shareholder in Estuar Pharmaceuticals.
Prof Louise Serpell: Professor Louise Serpell is an Emerita Professor of Biochemistry. She is a founder of Serpell-Science, a consultancy that advises on communication and research strategy for Neurodegenerative diseases.
Prof Masud Husain: I don’t have any conflicts of interest.
Prof Tara Spires-Jones: I have no conflicts with this study but have received payments for consulting, scientific talks, or collaborative research over the past 10 years from AbbVie, Sanofi, Merck, Scottish Brain Sciences, Jay Therapeutics, Cognition Therapeutics, Ono, and Eisai, and direct a company Spires-Jones Neuroscience, Ltd to act as a consultant. I am also Charity trustee for the British Neuroscience Association and the Guarantors of Brain and serve as scientific advisor to several charities and non-profit institutions.
For all other experts, no reply to our request for DOIs was received.