For Black Americans, Cardiovascular Risks in Adolescence Are Linked with Worse Late-Life Cognition
By Thomas R. Collins
September 17, 2020
Article In Brief
Having two or more cardiovascular risk factors as early as adolescence in Black teens was associated with poor semantic memory, verbal episodic memory and executive function later in life.
In a study that examined health data for young African Americans, cardiovascular risk factors as early as adolescence showed trends of association with worse cognition later in life, according to findings presented at the virtual Alzheimer's Association International Conference.
Having two or more of four risk factors earlier in life—being overweight or obese, hypertension, hypercholesteremia, and diabetes—were linked with poorer executive function, semantic memory, and verbal episodic memory years later, said Rachel Peterson, PhD, MPH, MA, a postdoctoral fellow of epidemiology at the University of California, Davis.
Cardiovascular risk factors have increasingly been shown to increase the risk of cognitive impairments, and African Americans could be at an especially high risk since they are more likely to have cardiovascular risk factors than whites.
“Most of the research that looks at these factors tends to look in mid-life—often late 40s, 50s and older—to see these associations,” Dr. Peterson said. But survey data show that these cardiovascular risk factors tend to start fairly early in life.
“So the question is how these earlier life-course cardiovascular risks may be associated with late-life cognitive health,” she said.
Researchers with the Study of Healthy Aging in African Americans (STAR) examined previously collected data from health check-ups for 722 people in the Kaiser Permanent Northern California health system. They divided participants into three categories: “adolescent” which was ages 12 to 20 at the time of the first check-up, “young adulthood”, ages 21 to 34, and “adulthood”, ages 35 to 56.
Participants were considered to be overweight or obese if they had a body mass index (BMI) of at least 25; to have hypertension if they had a blood pressure of 140/90, an older benchmark due to the criteria at the time of measurement; hypercholesteremia if they had total cholesterol of 200 or higher; and diabetes if they had a fasting glucose of at least 120 or non-fasting glucose of at least 200. They were also considered to have these conditions if a physician had diagnosed them or if they were on medications for those conditions, Dr. Peterson said.
As expected, the cardiovascular risk factors increased with age. And a high number of those in adulthood groups had at least one risk factor—nearly 40 percent were overweight or obese, and more than 50 percent had high cholesterol, she said.
The STAR research team later used the Spanish and English Neuropsychological Assessment Scales to assess the cognition of the participants, who were age 60- to 80-years-old by that time.
Researchers found that having diabetes or having two or more of the risk factors were associated with lower executive function (ß=-0.5 and -0.18, respectively). Having two or more of the risks was associated with lower semantic memory (ß=-0.22). And having two or more of the risks was associated with lower verbal episodic memory (ß=-0.27).
“Across the board for all our cognitive domains, having two or more cardiovascular risk factors is associated with lower cognitive assessments in late life,” said Dr. Peterson, adding that researchers saw trends that deserve more exploration, not statistically significant associations.
When they looked at age-stratified data, they found that diabetes in adolescence had a stronger association with lower executive function than diabetes in the pooled analysis. And they found that hypertension in early adulthood had a stronger association with lower executive function than in the pooled analysis.
“There may be some patterns with diabetes and hypertension emerging earlier among African Americans, which have a greater impact on late-life cognition, but these really need to be explored further,” she said.
Still, she said, the data point to the possibility that earlier intervention could have a benefit on later cognitive health.
“This study suggests that targeting our interventions to reduce or prevent these risk factors as early as possible in the life course may help to reduce late-life cognitive disparities among African Americans.”
Jennifer Manly, PhD, professor of neuropsychology at Columbia University, said the assessment of risk factors as early as adolescence is “a major contribution to our knowledge about these links.”
“These data are unique,” she added.
Establishing causal links is accomplished more easily when the risk is measured directly, as in this study, rather than asking study participants what their blood pressure was at some age in the past, she said.
“One thing the investigators can't do,” she cautioned, “is determine whether cognitive function was always lower in the groups with worse cardiovascular disease. In other words, this might not represent change over time.”
She added, “The other major contribution of this study is that they are all non-Latinx Black people. There are very few cohorts of Black people that have adolescent cardiovascular status and later-life cognitive function, and that is important because we are trying to figure out what causes Black people to be at higher risk for dementia, and we need more information like this study to increase our understanding.”
“High burden of cardiovascular disease is linked to racism, discrimination, poverty, residential segregation, limited educational opportunities, and exposure to pollution,” Dr. Manly said. “From a public health perspective, these are the systems that need to change.”
Carey Gleason, PhD, MS, associate professor of geriatrics and gerontology at the University of Wisconsin, said the findings deepen the understanding of how cardiovascular risk is linked with dementia.
“We know that mid-life cardiovascular risk factors are associated with risk for dementia—these findings expand the association to adolescence,” she said. “The findings add urgency to addressing factors that contribute to poor health in Black communities. Phenomena like food deserts and racism appear to have life-long effects on health—well beyond adolescence.”
Dr. Gleason said she thinks dementia is only one of many illnesses connected to adverse social determinants of health.
“Pediatricians,” she said, “can join geriatricians in calling for cities and towns to promote the health of all their citizens.”
Drs. Peterson, Manly, and Gleason reported no relevant disclosures.