Healthy living can counteract a high genetic risk of Alzheimer’s, study suggests

A healthy lifestyle can reduce the risk of developing Alzheimer’s or other forms of dementia even for those with a higher genetic risk of developing these mind-destroying diseases, according to new research.

People with a high genetic risk and poor health habits were about three times more likely to develop dementia than were people with a low genetic risk and good habits, researchers reported this week at the Alzheimer’s Assn. International Conference in Los Angeles.

Regardless of how much genetic risk someone had, a good diet, adequate exercise, limiting alcohol and not smoking made dementia less likely, the study authors found.

“I consider that good news,” said John Haaga of the U.S. National Institute on Aging, one of the study’s many sponsors. “No one can guarantee you’ll escape this awful disease,” but you can tip the odds in your favor with clean living, he said.

About 50 million people have dementia, and Alzheimer’s disease is the most common type. Genes and lifestyle contribute to many diseases, but researchers only recently have had the tools and information they need to conduct large studies to see how much each factor matters.

One such study a few years ago found that healthy living could help overcome one’s genetic risk for heart disease. Now researchers have shown the same to be true for dementia.

Dr. Elzbieta Kuzma and colleagues at the University of Exeter Medical School in England used the UK Biobank to study nearly 200,000 people 60 or older with no signs or symptoms of dementia at the start. Their genetic risk was classified as high, medium or low based on dozens of mutations known to affect dementia. They also were grouped by lifestyle factors.

After about eight years of study, 1.8% of those with a high genetic risk and poor lifestyles had developed dementia, compared with 0.6% of people with low genetic risk and healthy habits.

Among those with the highest genetic risk, just over 1% of those with favorable lifestyles developed dementia, compared with nearly 2% of those with poor lifestyles, the researchers found.

The results were published in the Journal of the American Medical Assn.

The study authors cautioned that their data was focused on people of European ancestry, so they don’t know whether the same is true for other racial or ethnic groups.

Still, the results should give encouragement to people who fear that gene mutations alone determine their destiny, said Dr. Rudy Tanzi, a genetics expert at Massachusetts General Hospital. Less than 5% of the mutations tied to Alzheimer’s are “fully penetrant,” meaning that they guarantee you’ll get the disease, he said.

“That means that with 95% of the mutations, your lifestyle will make a difference,” Tanzi said. “Don’t be too worried about your genetics. Spend more time being mindful of living a healthy life.”

A previous study in Sweden and Finland rigorously tested the effect of a healthy lifestyle by assigning one group of people to follow one and including a comparison group that did not. That study also found that healthy habits could help prevent mental decline.

The Alzheimer’s Assn. is sponsoring a similar study underway now in the United States.

In February, the World Health Organization released new dementia prevention guidelines that emphasize the benefits of healthy living.

Marchione writes for the Associated Press.