- Obesity, high blood pressure, and high blood sugar levels in young adults may be linked to greater declines in thinking and memory later in life, according to new research.
- More research is needed to know what effect managing these risk factors in young adulthood has on late-life cognitive abilities.
Young adults with risk factors for cardiovascular disease — high blood pressure, obesity, or high blood sugar levels — may also have a higher risk for greater cognitive declines later in life, suggests a new study.
“[The results from our study] are striking and suggest that early adulthood may be a critical time for the relationship between these health issues and late-life cognitive skills,” study author Dr. Kristine Yaffe, a cognitive aging and dementia researcher at the University of California, San Francisco, said in a press release.
People can modify, treat, or manage these risk factors with medications or lifestyle changes, such as diet and exercise.
Addressing them is already known to boost heart health, but may be good for the brain as well.
“It's possible that treating or modifying these health issues in early adulthood could prevent or reduce problems with thinking skills in later life,” Yaffe said.
The new study was published online March 17 in the journal Neurology.
Cardiovascular risk factors in young adulthood
For the new study, Yaffe and her colleagues pooled data from four other studies, which included a total of more than 15,000 adults 18 to 95 years old who were followed for 10 to 30 years.
These studies included measurements of people’s cardiovascular risk factors, including body mass index (BMI), fasting blood sugar level, systolic blood pressure, and total cholesterol.
Two of the studies, which included only older adults, also measured people’s cognitive abilities every 1 to 2 years.
Because these two studies began when participants were older, the authors of the new study had to estimate the participants’ early and midlife cardiovascular risk factors.
Yaffe and her colleagues analyzed the data to see whether cardiovascular problems in early adulthood, middle age, or later life were linked to greater declines in late-life scores on thinking and memory tests.
They found that people who had obesity, high blood pressure, or high blood sugar levels at any of the three life stages were more likely to have a greater decline in cognitive skills later in life.
The results were similar even when researchers took into account other factors that could affect cognitive abilities, such as age, sex, and education.
Having high total cholesterol during any life stage wasn't linked to greater cognitive decline later in life.
The link between these risk factors and late-life cognitive decline was greatest for younger adults, those in their 20s and 30s: The decline was 80 to 100 percent greater than what was seen in people without these health issues, the researchers wrote.
This was still true when researchers took into account people’s risk factors in midlife and late-life.
Few of the younger people had high blood sugar levels, but for those who did, there was a dramatic effect on late-life cognitive abilities.
“With more young people developing diabetes and obesity in early adulthood, along with higher levels of underdiagnosed and undertreated cardiovascular problems, this could have significant public health implications for cognitive health in late life,” Yaffe said.
More research needed to understand association
Dr. Christian Camargo, a neurologist with the University of Miami Evelyn F. McKnight Brain Institute, said we should be careful how we interpret these results.
Since this was an association study, it doesn’t show that cardiovascular risk factors in early adulthood cause cognitive decline in late-life, only that there is a link between them.
A few smaller studies, though, have found similar results.
One 2017 study found that higher blood sugar levels in young adults were linked to lower cognitive abilities in midlife.
A 2018 study found that better cardiovascular health at a younger age was associated with a lower risk of dementia in older age.
Camargo also cautions that just because these risk factors are linked to a bad outcome, in this case late-life dementia, reversing them won’t necessarily prevent dementia.
He points to a 2019 study in the journal JAMA that found intensive blood pressure control in people over age 50 did not reduce the risk of dementia.
However, he said this new study suggests several potential directions for future research.
For example, how do cardiovascular risk factors in early adulthood affect a person’s risk of late-life vascular dementia compared with Alzheimer’s?
Vascular dementia is a type of cognitive impairment due to reduced blood flow to the brain. It can occur alongside Alzheimer’s disease but can also occur by itself.
In addition, research is needed to know what effect managing these risk factors in young adulthood — such as through medications or lifestyle interventions — has on late-life cognitive abilities.
Even though more research is needed to understand the link between obesity, high blood pressure, and high blood sugar levels and late-life cognitive decline, there’s still benefit in treating or managing these health issues early in life.
“They’re called cardiovascular risk factors for a reason, because they’re bad for you,” Camargo said. “So, you’ll want to treat them anyway.”
And for physicians? “This reminds them to be a little more mindful of these risk factors in their earlier-age patients,” he said.