One in ten people over the age of 70, an unexpectedly high proportion, meets the criteria to be offered drug treatment for Alzheimer's disease, according to the first population-based study in the field.
The study, published in the journal Nature, was led by researchers at the University of Gothenburg, King's College London and Stavanger University Hospital. The research is based on a collaboration with the large Norwegian population study Helseundersøkelsen i Trøndelag (HUNT).
The current study provides the first population-based data on the prevalence of neuropathological changes in Alzheimer's disease, an important factor behind the development of dementia. The picture of how common these changes has previously been based on estimates.
Based on the Norwegian population study, 11,486 blood samples were analyzed from participants over 57 years of age in the local population. What was measured was a biomarker for protein deposits in the brain (p-tau217) that leads to the death of nerve cells and synapses, which is crucial for memory.
High age is a major risk factor
Through the blood test analyses, the researchers were able to determine that eleven percent of the participants over 70 met the criteria to be offered the drugs that can potentially slow cognitive decline, and which have become available in an increasing number of countries.
The analyses also showed that the Alzheimer's-related changes increased with increasing age. The relevant biomarker was found in the blood of almost eight percent of the participants aged 65 to 69, and in just over 65 percent of those over 90.
In the group of people over 70 with dementia, the marker was found in 60 percent. In people in the same age group, with mild cognitive impairment, the proportion was 32.6 percent. In those over 70 without symptoms, the Alzheimer's-related changes were found in 23.5 percent.
- If they live another ten years, it most likely that symptoms will arise, but the important thing in this study is the large group of elderly people who already have early symptoms and where there is an opportunity to offer treatment, says Henrik Zetterberg, professor of neurochemistry at the University of Gothenburg and chief physician at Sahlgrenska University Hospital.
Early detection is crucial
The study challenges the notion that Alzheimer's disease mainly affects women. There were no gender differences in any of the age groups. However, the study was able to establish that the neuropathological changes were less common in those with higher education.
Based on the results, the researchers assess that dementia due to Alzheimer's disease is more common in the group from 70 years of age than previously thought, but that the proportion with Alzheimer's-related changes in the younger age groups was lower than expected.
The increase in Alzheimer's disease, mainly as a result of us living longer, is described as a global challenge, where early detection is crucial. The researchers are now further investigating how blood-based biomarkers can predict the development of dementia.
Study: Prevalence of Alzheimer's Disease Pathology in the Community - The HUNT Study
