LONDON — In the packed halls of the recent Alzheimer's Association International Conference in mid-July, over 10,000 experts in brain research discussed strategies to beat dementia. But in one room, attendees gathered to watch a video from a nonscientist named Isabel Beltre, whose life was transformed by a recent trial.

Beltre was one of 1,200 participants ages 60 to 77 who took part in the Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline (LatAm-FINGERS), the first trial to test a culturally adapted lifestyle intervention to prevent cognitive decline in Latin America. Rather than attempting to treat dementia after it has developed, the trial tackled risk factors that raise the likelihood of the condition, like smoking and a sedentary lifestyle.

In her native Spanish, Beltre thanked both God and the project for its impact on her life. There was a celebratory air in the conference room as the trial's results were released. The lifestyle interventions, which included exercise programs and brain training, had statistically improved participants' thinking skills, compared with a control group who received only bare-bones support, like general health advice.

Trials like LatAm-FINGERS — including a related U.S.-based trial called the POINTER study — ultimately aim to cut rates of dementia around the world. The LatAm trial is the most successful of these trials to date, raising hopes that this approach could help to prevent dementia en masse.

Whether that promise pans out remains to be seen, though, experts told Live Science.

The lifestyle factors that increase dementia risk

When it comes to dementia prevention, few guidelines are as influential as those written by the Lancet Commission, an expert-led review of the available evidence on dementia. Three editions of this review have provided comprehensive overviews of risk factors; the most recent, published in 2024, identified 14 factors, including smoking, infrequent social contact, and a lack of physical activity.

The commission estimated that, together, the identified risk factors contribute to 45% of dementia cases at a population level.

Long before the 2024 report, Dr. Miia Kivipelto, a professor of clinical geriatrics at the Karolinska Institute in Sweden, wanted to tackle these risk factors at the individual and population level in her work as a medical doctor and epidemiologist.

"I felt that I wanted to move on to interventions to really show that if you do something, you can change the risk," Kivipelto told Live Science.

The many contributing factors that lead to cognitive decline, and ultimately dementia, couldn't be tackled in isolation, Kivipelto realized. She designed a trial in her native Finland, called the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) study, that would aim to tackle many risks simultaneously.

The two-year project recruited 1,260 participants ages 60 to 77 and divided them into two groups. The first group received general health advice, such as tips on healthy eating and exercise, at the start of the study and then again after six and 12 months.

The other group additionally received a multipart intervention consisting of meetings with nutritionists to discuss personalized meal plans, brain training, exercise programs, social activities, and metabolic and vascular tests. These programs lasted throughout the study period, with the brain training alone including 144 sessions over 12 months of the study.

At the end, the two groups' cognitive skills, such as thinking speed and memory, were tested; the trial did not track dementia rates, only overall cognition. In both groups, these skills improved by the end of the study. But the headline finding was that in the group given the comprehensive intervention, overall brain function was judged to be 25% stronger than in the control group.

What did that difference mean in concrete terms? It turns out, the improvement was relatively small.

It was calculated in terms of a statistical measure called a z-score, which represented the extent of the improvement in brain-function test scores in each group. In the end, the difference in z-scores between the two groups was just 0.04 points, which a 2021 review defined as "small."

However, Kivipelto maintained that the improvement is significant. "It's as big as anti-amyloid treatments," she said.

Several drugs approved by the U.S Food and Drug Administration for the treatment of Alzheimer's disease target amyloid, a protein that forms unruly tangles in the brain. These drugs have been reported to marginally slow the disease's progression, but statistically, their overall effect is small.

Targeting those most at risk of dementia

Despite criticism of the trial's moderate effects, Kivipelto's FINGER intervention has since been repeated all over the world, including by the U.S.-based POINTER study, and, most recently, LatAm-FINGERS.

Dr. Gill Livingston, a psychiatrist at University College London who led the 2024 Lancet Commission report, told Live Science that the data from these trials shows that dementia interventions need to be tailored to the risks the participants actually face.

In the POINTER study, 70% of the participants had a college degree, compared with roughly 43% of the wider U.S. population. "People who are usually in randomized controlled trials are usually highly educated people who are very interested in health," Livingston noted. "And that means they're at less risk of developing dementia, and therefore, less can be done to help them" through lifestyle interventions.

The difference between the test group and the control group in the POINTER study was even smaller than in the original FINGER trial — just 0.029 points.

LatAm-FINGERS tried to maximize flexibility in its approach by better tailoring its interventions to its study participants, said study first author Dr. Lucía Crivelli, a neuropsychologist at the neurology center FLENI in Argentina. Dietary advice reflected the produce available in each region. Exercise programs considered local environmental factors; for example, sessions were held outside, avoiding hot gyms during the sweltering summers in Ecuador and Mexico.

The trial recruited volunteers across Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, Ecuador, Mexico, Peru, Puerto Rico, the Dominican Republic and Uruguay. The participants were less highly educated than the POINTER cohort had been; 37% had no education beyond a high school diploma, compared to just 5% in the POINTER study. That likely made the study participants more representative of people who might benefit from the trial's interventions.

When Crivelli announced the results of the trial at the conference, a large cheer filled the room. The intervention had achieved a difference of 0.11 points between the test and control groups' z-scores — more than twice the difference seen in the FINGER trial.

That difference corresponded to a relative 55% improvement in overall brain function in the test group compared to the control group at the end of the study.

What made the difference?

Crivelli, Kivipelto and Livingston all pointed to one key factor in explaining the project's relative success. "In Latin America, there are more modifiable risk factors," Kivipelto summarized.

The study participants had lower academic attainment and higher cardiometabolic risk factors, such as high BMI, than the participants in previous studies. The trial had reaped the rewards of delivering the intervention to people who needed it most, experts concluded.

But the approach wasn't perfect. said Dr. Claudia Suemoto, a neuroscientist at the University of São Paulo who presented a detailed breakdown of the trial's results. They found that the intervention didn't improve men's overall cognitive ability, compared with the control group. Only women benefited.

The difference may be that men simply didn't engage in the trial as much as women did, Suemoto's data suggested. Livingston pointed to the trials' exercise classes as an example of an activity that men may not be as likely to participate in, although that's an assumption rather than being based on the trial data.

Can we really prevent dementia?

The LatAm-FINGERS results show that addressing the dementia risk factors that people face is the most effective way to prevent dementia, Livingston said.

And Livingston is leaning into the idea. She's planning a dementia prevention trial in the U.K. that will ask participants about their risk factors and then give them tailored interventions based on the risks they can realistically avoid.

"We ask them to choose which ones they want," Livingston said. "If somebody doesn't want to stop drinking or smoking, then they're not going to."

While LatAm-FINGERS has been the most successful of the FINGER trials to date, it's still unclear whether such projects actually reduce dementia rates.

Only two previous prevention trials have attempted to measure dementia incidence, and neither saw a notable change in their test group. That said, neither trial included cognitive training interventions like FINGER did; they instead focused on cardiovascular risk factors, such as low exercise rates and high body weight.

Measuring changes in dementia rates requires trials much longer than two years, and they also need massive recruitment. Implementing an intensive study like LatAM-FINGERS in the wider community "is not practical," Crivelli said. Instead, she said the study's interventions would need to be distilled into their essential parts so that they could be implemented at scale.

Kivipelto is optimistic that advances in Alzheimer's screening, including new blood-based tests, could provide an early biological measure to show that FINGERS-style interventions can help stave off dementia. This would be an indirect measure but wouldn't require as long a trial as tracking dementia rates.

Some of the risk factors the Lancet Commission identified, like air pollution, can't be modified at an individual level, Livingston noted. A combination of personal and governmental change could address this, she said, as it has in the realm of infectious-disease prevention.

While the scientific field still has uncertainty about the scale of change that trials like FINGERS can bring about, Beltre has little doubt about the trial's impact.

While she previously relied on help from family members like her grandson to complete everyday activities, she said, "I do everything myself now."

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