The onset of dementia can come as a shock, but various signs could predict the condition as long as 20 years before symptoms.

A new study published by the RAND Corporation in California identified several major predictors occurring around age 60 that are likely to lead to cognitive impairment and dementia in individuals by age 80.

Researchers evaluated 181 potential risk factors, including demographics, socioeconomic status, lifestyle and health behaviors, health history, psycho-social factors and more.

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Below are some of the strongest predictors at age 60 that indicate a higher chance of developing cognitive impairment and dementia, according to the report.

See the list of 14 predictors. 

Woman sad on couch

RAND researchers uncovered several surprising predictors of dementia risk, like never drinking and never working. (iStock)

1. Poor physical health

2. History of stroke

3. Genetics

4. Being born in the Southern United States

5. Not having private health insurance at age 60

6. Never working or only working for a few years

7. History of diabetes

8. Having a body mass index of 35 or more

9. Never drinking alcohol or drinking excessively

10. Never exercising

11. Scoring low on physical tests

12. Being less conscientious

13. Low engagement in hobbies

14. Low cognitive function and engagement

Parental health, family size, marital history and demographics were the weakest predictors, according to the research.

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In an interview with Fox News Digital, study co-author Peter Hudomiet, a RAND economist in California, shared details of the study, which worked with a large dataset and followed individuals "for decades."

Senior Couple Sitting On The Bed And Looking Away

Parental health, family size, marital history and demographics were the weakest predictors, according to the research. (iStock)

"Overall, we found that risk factors had a similar effect in the short and long term, which reassured us that the findings from prior literature may hold in the long term," he said.

"Nevertheless, we also had quite a few surprising findings."

Digging into dementia drivers

The researcher said he was surprised to find that those who never exercised had a "substantially higher chance" of developing dementia than those who lightly exercised at least a few times per month.

"Exercising even more often (weekly or daily) had some additional benefits, but not that much," he noted.

"In other words, the main risk factor for dementia was never exercising."

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"These behavioral factors were more important predictors of dementia than having the right genes," Hudomiet added.

While having a body mass index (BMI) over 30 at age 60 was a weak predictor of dementia, a BMI over 35 was a "powerful predictor."

woman sitting on an exercise mat doing yoga and stretching

The risk of dementia is "about half as much among those who regularly exercise compared to those who never do," said the researcher (not pictured). (iStock)

Never participating in cognitive activities offered a much higher risk of developing dementia compared to sometimes participating, as well as only having zero to 11 years of education compared to having high school or advanced degrees, said Hudomiet.

Another unexpected finding was the substantially higher dementia risk faced by Americans born in the Southeastern U.S. compared to the rest of the country.

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"This differential remained strong even when our statistical models accounted for differences in income, health, and other differences between regions," the researcher noted.

"It is possible that the quality of education (which we could not measure in our data) was lower in the Southeastern part of the U.S., especially in the older cohorts we analyzed."

nurse holding hands with a senior patient

"Less than 1% of health care dollars go toward educating the public on positive health care strategies," according to a gerontologist.  (iStock)

People not covered by a private health insurance plan at age 60 had an 11% higher chance of developing dementia than those who had coverage, Hudomiet added.

That's "partly because private health insurance helps individuals remain healthy longer," he suggested.

"The choices you make now will determine how you will live later."

The study results suggested that "maintaining good physical and mental health is beneficial not just to staying in shape, but also to staying sharp and delaying cognitive decline," Hudomiet told Fox News Digital.

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Gerontologist Dr. Macie P. Smith in South Carolina, who was not involved in the study, also reacted to the findings in a separate interview with Fox News Digital, saying the researchers are "spot on."

"Having this researched information presented … brings about a heightened sense of responsibility to everyone who claims to be in the fight to end Alzheimer’s disease and related dementias (ADRD)," she wrote in an email response.

Elderly father adult son and grandson out for a walk in the park.

A person's genetics are less of a risk factor than certain habits and behaviors such as exercise, a researcher noted. (iStock)

Smith said it is "pretty shocking" that never drinking alcohol increases dementia risk.

"This stands out to me because drinking alcohol excessively increases one’s risk significantly of brain deterioration and can lead to alcohol-induced dementia," she said. 

The expert suggested that self-reported data could have led to this finding — or red wine could have been factored in, as it’s been found to "contain brain-enhancing nutrients, such as resveratrol."

Ways to reduce the risk

While cognitive decline is sometimes impossible to prevent, Hudomiet mentioned that some risk factors can be reduced through lifestyle changes.

These include exercising regularly, maintaining a healthy body weight, getting proper nutrition and engaging in challenging cognitive activities.

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"Health care providers and the government should consider promoting healthy behaviors in the adult population and strengthening individuals’ access to quality health care, which may decrease the prevalence of dementia and the burden of the disease in the future," Hudomiet recommended.

Older woman reading

"Understanding that what’s good for the heart is good for the brain and adopting healthy lifestyle practices puts people in control of their brain fate," one expert said. (iStock)

Smith added that reducing dementia risk "doesn’t begin or end with medication."

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For those who are middle-aged, paying attention to these early predictors is a "matter of life and death," she stated.

"It is incumbent on everyone with a brain to take heed of the warning signs that your body gives you," she said. "Your body always reminds you about what your brain sometimes ignores."

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"You have the power to take control over what your life looks like down the road," she went on. 

"The choices you make now will determine how you will live later."