Researchers reported Sunday at the Alzheimer's Association International Conference that it was possible to delay dementia, even in people at genetic risk. Several studies show that the key is not a factor, but a combination of healthy lifestyle habits. And the more a person adopts healthy habits, the lower the risk of cognitive decline.
People who followed four out of five lifestyle habits, including regular exercise, cognitive stimulation, a healthy diet for the brain and the ban on smoking, presented a risk of developing dementia. Alzheimer's 60% lower than that of people who practiced only one. or none of these habits, according to researchers at Rush University in Chicago.
Similarly, a British study found that among people with a high genetic risk of cognitive decline, dementia was 32% lower among those with a healthy lifestyle.
In a third study at the University of California at San Francisco, researchers found that smokers were twice as likely to develop a cognitive impairment as non-smokers and those who had taken the habit .
"This reinforces the idea that some of these lifestyle-related factors may actually affect the trajectory of cognitive aging and the development of dementia," said Dr. Ronald Petersen, director of the Center for Disease Research. Alzheimer's of the Mayo Clinic. "We certainly accept that with heart disease. We must adopt a similar state of mind for cognitive aging. "
For people who fear that dementia is unavoidable because of their family history or genetic profile, it tells them that "the game is not over because they have increased the risk," he said. Petersen, who was not affiliated with the new studies.
The Rush study analyzed data from 1,845 participants in the Chicago Health and Aging Project and 920 participants in the Rush Memory and Aging Project who had no early dementia. Participants received lifestyle scores that depended on the number of healthy behaviors out of five that they had enrolled:
- no smoking
- exercise at a moderate to vigorous level for at least 150 minutes a week
- consume a diet supporting the brain
- light to moderate alcohol consumption
- engage in late cognitive activities
Each behavior has a zero or one, for a possible maximum score of five.
What is the MIND diet?
Participants' diets were evaluated according to their similarity to the "MIND" (Mediterranean-DASH Intervention for Neurodegenerative Delay), composed of leafy greens, beans, olive oil, nuts and poultry, while avoiding the meat, the fried foods, said the author of the study, Dr. Klodian Dhana, at NBC News. People with a diet in the top 40% have one point for what they consume, while others have zeros.
In about six years of follow-up, 608 participants developed Alzheimer's dementia. When the researchers analyzed their data, they found that the risk of Alzheimer's disease was 37% lower among people who adopted two or three healthy behaviors, and 60% lower among those who practiced four to five of these behaviors. , compared to those with a zero or one score.
According to the Centers for Disease Control and Prevention, Alzheimer's disease is the sixth leading cause of death in the United States. It is the most common form of dementia and the risk of Alzheimer's disease is generally higher in people with the APOE4 genetic mutation.
"But among this group, those who followed a healthy lifestyle saw their risk of dementia decrease," said Dhana.
The British study, which was also published in JAMA Neurology, followed 196,383 adults who participated in Biobank in the UK and who were all at least 60 years old and did not have early dementia of the study. Each group was assigned a risk score for dementia based on genes associated with an increased risk of dementia and a higher lifestyle score based on the number of reported healthy behaviors.
In the six years of follow-up to the UK study, 668 cases of dementia were identified, the odds being higher for those with a high genetic risk score. But the researchers reported that the risk was more than halved for participants with a high genetic factor but who adopted a healthy lifestyle. This would represent a case of dementia avoided for 121 people with high genetic risk over a 10-year period.
Can we prevent Alzheimer's disease?
The study shows that "leading a healthy lifestyle is associated with a reduced risk of dementia, regardless of genetic risk," Elzbieta Kuzma, co-author of the study and researcher in neuroepidemiology at NBC News, told NBC News. University of Exeter Medical School.
With so few drugs to treat Alzheimer's disease, the new studies "are a great way to steer us in research," said Juleen Rodakowski, assistant professor in the occupational therapy department at the University of Pittsburgh.
The studies are certainly good news, but they do not make it possible to know if a healthy lifestyle slows down the pathology at the origin of the brain in people suffering from Alzheimer's disease or simply by reinforcing it. resilience, said Dr. Jason Brandt, professor. in the Departments of Psychiatry and Behavioral Sciences and Neurology at the Johns Hopkins School of Medicine.
However, there are allusions to animal research, he added.
"If you administer genetically engineered mice to create an enriched environment in Alzheimer's disease, you will get better results in memory tests and, under the microscope, less amyloid substance," one of the proteins that disgust the brain of people with Alzheimer's disease. patients with the disease, said Brandt.