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Healthy lifestyle may lower risk of dementia, even when genetic risk is high, study suggests

REUTERS/Lucy Nicholson
Scientists believe both genetic and lifestyle factors help determine an individual’s risk of developing dementia.

Following a healthy lifestyle, including eating a plant-based diet and exercising regularly, may help lower the risk of developing dementia — even among people with a high genetic risk for dementia, according to a study published online Sunday in the Journal of the American Medical Association (JAMA) and presented Monday at the Alzheimer’s Association International Conference (AAIC).

Specifically, the study found that people with a high genetic risk were about a third less likely to develop dementia if they followed a healthy lifestyle than if they didn’t.

About 5 million people in the United States have some form of dementia, including Alzheimer’s disease, its most common form, according to the Centers for Disease Control and Prevention (CDC). There is currently no cure for the condition.

Scientists believe both genetic and lifestyle factors help determine an individual’s risk of developing dementia. But past studies that have tried to figure out just how much a healthy lifestyle might reduce the risk in people with a high genetic risk have produced inconsistent findings.

This new study is the first one that has been able to identify the extent to which a healthy lifestyle may offset the genetic risk of the disease, say its authors.

“Our findings are exciting because they show that we can take action to try to offset our genetic risk for dementia,” says Elzbieta Kuzma, one of the study’s authors and a research fellow at the University of Exeter, in a released statement. “Sticking to a healthy lifestyle was associated with a reduced risk of dementia, regardless of the genetic risk.”

Study details

For their study, Kuzma and her co-authors analyzed data from 196,383 British adults enrolled between 2006 and 2010 in UK Biobank, an ongoing research project aimed at finding better ways to prevent, diagnose and treat a wide range of serious and life-threatening illnesses, including dementia. At the start of the study, all the participants were at least 60 years old and none had dementia or any symptoms of cognitive impairment.

Using previously published data that has identified gene variants associated with dementia, the researchers categorized each participant as having a “low,” “intermediate” or “high” risk of developing the condition. Then, using the participants’ self-reported accounts of four lifestyle behaviors — smoking, alcohol consumption, physical activity and diet — they also gave each person a “favorable,” “intermediate” or “unfavorable” lifestyle score. (Not smoking, consuming alcohol only in moderation, exercising regularly and following a healthy diet were considered healthy behaviors.)

The study followed the participants for an average of eight years (through 2016 or 2017). During that period, 1,769 were diagnosed with dementia.

When the researchers analyzed the data, they found that 0.56 percent of the participants with a low genetic risk who maintained a healthy lifestyle developed dementia.

The risk was significantly higher for the participants with a high genetic risk who had a healthy lifestyle. In that group, 1.13 percent developed dementia.

But the highest risk was among the participants with a high genetic risk and an unhealthy lifestyle. The study found 1.78 percent of those individuals developed dementia.

Not always inevitable

The study comes with important limitations. The study was observational, and therefore can’t prove cause and effect. In addition, all the participants were of European ancestry. The results might have been different for a more ethnically diverse population.

It’s also important to point out that even if a healthy lifestyle can prevent dementia in some people, it is not able to do so for everyone. Many individuals will develop the condition no matter how conscientious they are about the foods they eat or the hours they exercise each week.

Still, the study’s authors find the findings encouraging — and hopeful.

“This research delivers a really important message that undermines a fatalistic view of dementia,” says David Llewellyn, the study’s senior author and a professor of neuroepidemiology at the University of Exeter, in a released statement. “Some people believe it’s inevitable they’ll develop dementia because of their genetics. However, it appears that you may be able to substantially reduce your dementia risk by living a healthy lifestyle.”

FMI: The study can be found on JAMA’s website.

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