LOS ANGELES - Even if you have a high genetic risk for developing Alzheimer's, new research has found that making healthy lifestyle choices can lower your overall risk for the disease, as well as your risk for other forms of dementia.
Researchers from Rush University Medical Center in Chicago found that a healthy diet, regular exercise, light to moderate alcohol intake, not smoking and engaging in cognitively stimulating activities reduced the risk of Alzheimer's by 60 percent -- when compared to those who only followed one or none of those habits.
The researchers found that even for people who adopted one more of these habits, whatever their current number of lifestyle factors, the risk of Alzheimer's dementia decreased by an additional 22 percent.
"This study highlights the importance of following multiple healthy lifestyle practices for lowering the risk of Alzheimer's dementia," said Dr. Klodian Dhana, an assistant professor at Rush University who participated in the study. "In the U.S., adherence to a healthy lifestyle is low, and therefore promoting these lifestyle factors should become the primary goal for public health policies."
The research was part of five studies reported at the Alzheimer's Association International Conference in Los Angeles.
About 50 million people have dementia worldwide, 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 to do large studies to see how much each factor matters.
One such study a few years ago found that healthy living could help overcome genetic risk for heart disease. Now researchers have shown the same to be true for dementia.
Another study, which included nearly 200,000 participants in the U.K., was also discussed at the conference and published online by the Journal of the American Medical Association.
Researchers at the University of Exeter Medical School in England used data from the UK Biobank to study participants, who were all 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 categorized by lifestyle factors based on their diet, physical activity, smoking and alcohol consumption.
People with high genetic risk and poor health habits were almost three times more likely to develop dementia versus those with low genetic risk and good habits, researchers found.
And regardless of how much genetic risk someone had, a good diet, adequate exercise, limiting alcohol and not smoking made dementia less likely.
"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.
The study only included information on mutations affecting people of European ancestry, so it was not known whether the same is true for other racial or ethnic groups.
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 percent of the ones tied to Alzheimer's are "fully penetrant," meaning that they guarantee you'll get the disease, he said.
"That means that with 95 percent 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."
One previous study in Sweden and Finland rigorously tested the effect of a healthy lifestyle by assigning one group to follow one and included a comparison group that did not. It concluded that healthy habits could help prevent mental decline.
The Alzheimer's Association is sponsoring a similar study underway now in the United States.
Healthy living also is the focus of new dementia prevention guidelines that the World Health Organization released earlier this year. A new case occurs every three seconds, and the number of people with dementia is set to triple by 2050, according to WHO.
The Associated Press contributed to this report.