Lifestyle choices at 60 linked to dementia risk decades later, study shows

Early predictors of dementia are emerging as critical tools for guiding health and lifestyle decisions long before symptoms appear.

The Health and Retirement Study, which looked at more than two decades of data from over 45,000 older adults in the United States, suggested that lifestyle, genetics and other factors at 60 years old can help predict brain health at 80.

"Our research confirmed that factors like low cognitive test scores and poor general health in one's 60s are strong predictors of dementia later in life," said Peter Hudomiet, the PhD-level researcher and economist at the RAND Corporation, who led the study, told ABC News.

"We also uncovered some surprising insights, such as the significant protective effect of education, particularly having a high school diploma, and the increased risk associated with living in the South," he added.

Among the study's findings, younger seniors who engaged in physical activity and mentally stimulating hobbies appeared to have a lower risk of cognitive decline. Conversely, those who led sedentary lifestyles and those who had few mentally stimulating interests to occupy their time were more likely to develop dementia by age 80. Excessive alcohol use was also bad for the brain, the study found.

"Lifestyle factors like minimal exercise, extreme obesity, and both excessive and no alcohol consumption also emerged as important contributors. These findings highlight the complex interplay of behavioral, social, and genetic factors in dementia risk," Hudomiet said.

Chronic health conditions including diabetes, obesity and stroke by the age of 60 were strongly linked to a higher chance of dementia later in life, according to the study.

Some groups were higher at risks than others, such as those born in a Southern state. Black and Hispanic people were also at higher risk as well, possibly because they lacked access to health care, the study said.

"We do see very large differences by socioeconomic status, measured in various ways -- for example, using education, income, wealth, and race. People with lower education, less income, less wealth, and racial minorities all face higher chances of dementia," Hudomiet said. "However, when we control for education and income, the racial disparities disappear, suggesting that the differences are related to socioeconomic factors."

This is good news, Hudomiet said, because it means addressing disparities could help close these gaps for high-risk groups.

While genetics and age can't be changed, the study emphasized that many other risk factors can be proactively addressed. For instance, getting regular exercise, finding a hobby, staying socially active and managing chronic conditions all may help keep the brain sharp. Limiting alcohol consumption, eating a healthy diet and getting good sleep all helped mitigate risk as well.

Kristine Yaffe, MD, professor of psychiatry, neurology, and epidemiology at the University of California at San Francisco said she thought the study added some impressive evidence for real strategies that help stave off dementia.

"The findings underscore the importance of genetics, behaviors, and lifestyle factors. In particular, they highlight critical considerations for promoting brain health across the life course," she said.

She urged people to start thinking about their brain health early.

"We need to increasingly think about ways to promote brain health, just as we focus on promoting cardiovascular health. This is something we should consider across every stage of life, not just when we're older and start worrying about memory," she said.

Despite its comprehensive findings, the study doesn't prove that changing lifestyle behaviors can help prevent dementia, only that they are associated with a lower risk of the disease. The authors call for further research to explore targeted interventions for a wider variety of people.

An estimated 6.9 million Americans are living with dementia, according to the National Institutes of Health. Those numbers will double by 2060, the Centers for Disease Control and Prevention projects.

Neil C. Bhavsar is an emergency medicine resident physician with New York Presbyterian, Columbia/Cornell and a member of the ABC News Medical Unit.