Study Quantifies Major Potential for Dementia Prevention
Greifswald/Boston, 9 December 2025. Around 36 percent of dementia cases in Germany are linked to risk factors that are, in principle, modifiable. These are the findings of a new study conducted by researchers from DZNE’s Rostock/Greifswald site and Harvard Medical School. The study is based on current data from the German Ageing Survey 2023 (DEAS), a nationwide, representative survey of people aged 40 and older.
Modifiable risk factors are influences that can be reduced through a healthy lifestyle, good medical care, or improved societal conditions. The international Lancet Commission identified a total of 14 such factors across the lifespan. Using data from the German Ageing Survey, the present study was able to examine 12 of them. The result: an estimated 36 percent of dementia cases can be attributed to these 12 modifiable risk factors. They include, among others, high blood pressure, hearing loss, elevated blood lipid levels, low educational attainment, and physical inactivity. These findings are in line with the Lancet Commission, which estimates that about 45 percent of all dementia cases worldwide could be prevented or delayed if all 14 known risk factors were addressed. “The added value of our study is that we have now examined this potential specifically for the situation in Germany,” explains Prof. René Thyrian from DZNE’s Rostock/Greifswald site.
Prevention could avert hundreds of thousands of cases
In Germany, an estimated 1.8 million people are currently living with dementia. Without additional prevention measures, this number could rise to around 2.7 million by 2050. Researchers Dr. Iris Blotenberg (Harvard Medical School) and Prof. René Thyrian calculated how many cases could theoretically be prevented or significantly delayed if modifiable risk factors became less common in the population. Their model calculation points to substantial potential: reducing risk factors by 15 percent could prevent about 170,000 cases by 2050; a 30 percent reduction could prevent more than 330,000 cases.
These factors weigh particularly heavily in Germany
According to the study, the strongest contributors to dementia prevalence are:
- depression
- hearing loss
- low educational attainment
- overweight/obesity
- diabetes
Many of these factors cannot be influenced by individual behavior alone. Medical care and social conditions also matter—for example, access to mental health services, hearing aids, or health education.
Risks are unevenly distributed: typical risk profiles
People do not all share the same risk of developing dementia. Therefore, in addition to estimating the overall risk, the researchers also examined typical risk patterns in the population. Using a statistical approach known as latent class analysis, they identified several risk profiles — groups of individuals with similar patterns of risk factors:
- Metabolic profile – about 18 percent: frequently high blood pressure, overweight/obesity, elevated cholesterol levels, and diabetes.
- Sensory profile – about 23 percent: mainly hearing and vision impairments.
- Alcohol profile – about 24 percent: increased risk related to alcohol consumption.
- Low-risk profile – about 36 percent: overall few risk factors.
The risk profiles are clearly associated with social and regional characteristics, including age, education, region, and urban–rural differences. People in eastern Germany and in rural areas are more likely to belong to risk groups. Older men and individuals with low educational attainment are also disproportionately affected.
An opportunity for tailored prevention measures
“To our knowledge, this is one of the first studies to describe such subgroups on the basis of nationally representative data for Germany,” says René Thyrian. “The results show that dementia prevention has enormous potential in Germany—and that risks are distributed very unevenly across the population. Prevention should therefore not follow a one-size-fits-all approach, but should target areas where risks cluster.”
First author Iris Blotenberg adds: “Our findings offer the opportunity to plan prevention measures more precisely—for example, with a stronger focus on mental health, hearing care, and metabolic conditions where the need is greatest. If prevention programs are adapted to typical risk patterns, we can prevent dementia more effectively and more fairly—while also reducing other diseases linked to these patterns.”
Data basis and methods
The Lancet Commission currently lists 14 modifiable risk factors for dementia across the lifespan. For Germany, available evidence has so far largely relied on older data. The present study uses representative data from the German Ageing Survey 2023 (nearly 5,000 participants aged 40 and older), published in March 2025. The research team combined these prevalences with international risk estimates to quantify the national prevention potential and to describe risk groups on a data-driven basis.
About Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE (German Center for Neurodegenerative Diseases): DZNE is one of the world’s leading research centers for neurodegenerative diseases such as Alzheimer’s, Parkinson’s and ALS, which are associated with dementia, movement disorders and other serious health impairments. These diseases place an enormous burden on patients and their families, but also on society and the economy of healthcare. DZNE contributes significantly to the development and translation into practice of novel strategies for prevention, diagnosis, care and treatment. DZNE comprises ten sites across Germany and collaborates with universities, university hospitals, research centers and other institutions in Germany and throughout the world. DZNE is state-funded and a member of the Helmholtz Association and of the German Centers for Health Research.