Dementia: New cases could double worldwide

Suddenly, the granddaughter’s name is gone, and the familiar walk to the bakery feels strange. This is how dementia begins for many families. Worldwide, about 11.4 million people are newly diagnosed each year. By 2050, that number could rise to nearly 25 million per year. This is shown by a new study published in the journal JAMA Neurology. The Institute for Social Medicine, Occupational Medicine, and Public Health at the University of Leipzig participated in the study.

The main reason is simple. People are living longer, and the risk of dementia increases with age. The team, led by the University of New South Wales in Sydney, analyzed data from more than 38,000 people aged 60 and older. The data came from 22 long-term studies in 18 countries and regions. In a meta-analysis like this, the results of multiple studies are combined and evaluated together. 

The team then calculated how many people might develop the disease for the first time in 2050. In doing so, the researchers assumed that the risk of developing the disease for women and men in the respective age groups would remain unchanged by that time.

Women and poorer countries more severely affected

The analysis also reveals differences. Women are more likely to develop dementia than men. This may not be due solely to their higher life expectancy. Cardiovascular diseases after menopause or poorer educational opportunities may also play a role.

In economically poorer countries, the rate of new cases is also higher than in wealthier nations. The researchers see one possible explanation in the fact that more is already being done for prevention in economically better-off countries.

However, the trend does not necessarily have to follow the path predicted by the model. “In fact, several long-term studies from Europe and North America show that the age-specific incidence of dementia has declined in some cases over the past decades,” says Prof. Steffi G. Riedel-Heller. She heads the Leipzig institute and was involved in the study. This means that in some countries, a proportionally smaller number of people within the same age group are developing the disease today than in the past.

“So this trend is not necessarily set in stone. Numerous risk factors can be influenced,” emphasizes Riedel-Heller. An international expert commission has compiled a list of 14 such risk factors. These include, among others, high blood pressure, smoking, hearing loss, and physical inactivity. According to their estimates, approximately 45 percent of dementia cases worldwide could be prevented or at least delayed if these risks were reduced. However, this is a mathematical estimate and does not mean that dementia can be reliably prevented in every individual case.

Leipzig seniors provide important data

Older adults from Leipzig have also contributed to the new findings. Data from the Leipzig long-term study LEILA 75+ were included in the international analysis. Since the late 1990s, participants from Leipzig have been examined repeatedly as part of this study. This allowed researchers to track how their mental health developed over an extended period. Combined with data from other countries, this provides a better understanding of how the risk of dementia varies among different population groups.

“Longitudinal studies like this one are indispensable for dementia research because they show how mental health develops over the years, which factors are associated with an increased risk of the disease, and where prevention efforts can be targeted,” explains Riedel-Heller. The Leipzig-based researcher has been studying how to reduce the risk of dementia for many years. Other studies from Leipzig also suggest that prevention should begin early in life.

In the nationwide NAKO health study, researchers found a link between a higher score on a dementia risk index and lower cognitive function even among young adults. This does not mean that these people will inevitably develop dementia later in life. However, it does show that factors related to brain health play a role even at a young age.

It is not just a matter of whether people get enough exercise, eat a healthy diet, or avoid smoking. Education, medical care, and living conditions also play a role. “This isn’t just about individual behavior. We also need to shape living conditions in such a way that healthy aging is possible for everyone,” says Riedel-Heller.

At the same time, society must prepare to care for more people with dementia in the future. Even if we succeed in reducing the risk of developing the disease, the aging global population means that more people are likely to require support and care.


Original publication:
Vella AS, Visontay R, Lipnicki DM, et al. Global Incidence of All-Cause Dementia: A Meta-Analysis. JAMA Neurol. Published online October 12, 2026.