High BMI, other health factors when young may increase later risk for Alzheimer’s disease

Liz Seegert

About Liz Seegert

Liz Seegert (@lseegert), is AHCJ’s topic editor on aging. Her work has appeared in NextAvenue.com, Journal of Active Aging, Cancer Today, Kaiser Health News, the Connecticut Health I-Team and other outlets. She is a senior fellow at the Center for Health Policy and Media Engagement at George Washington University and co-produces the HealthCetera podcast.

Poor cardiovascular health and a high body mass index during a person’s teens and 20s may be early predictors for developing Alzheimer’s disease later in life, according to research presented last week at the Alzheimer’s Association International Conference.

The research, presented in a virtual poster session, demonstrates the importance of preventive efforts at a younger age, especially among African Americans disproportionally affected by high blood pressure, high cholesterol, diabetes and similar conditions.

Older African Americans are about twice as likely to develop Alzheimer’s or other dementias as older whites, according to the Alzheimer’s Association. Identifying, verifying, and acting to counter these modifiable risk factors may help reduce new cases and, eventually, the total number of those with dementia.

“The research assessing cardiovascular risk factors and cognition has primarily focused on middle age or older adults,” noted Kristen George, Ph.D. MPH, who was lead author on one of the studies presented. “Much less is known about the effects of cardiovascular risk factors developed in adolescence and young adulthood on late-life brain health.”

“This is an especially important topic for Black Americans, who often have a higher prevalence of CVD risk factors and are at greater risk of developing dementia compared to other racial or ethnic groups,” said George, a postdoctoral scholar in the Department of Public Health Sciences at the University of California, Davis, in an email. “Our findings suggest that efforts to promote heart-and brain-healthy lifestyles must include younger adults and even adolescents who may be especially susceptible to the negative long-term effects of poor cardiovascular health on the brain.”

The research team looked at data from some 700 African American adolescents (ages 12-20), young adults (21-34) and adults (35-56) enrolled in the Study of Healthy Aging in African Americans (STAR). They found that high blood pressure and diabetes, or a combination of multiple heart health-related factors, are common in adolescence and are associated with worse late-life cognition. Cognition was measured using in-person tests of memory and executive function. The mean age at cognitive assessment was 68.

African Americans who were older than 50 and had diabetes, high blood pressure or at least two other CVD risks from adolescence to mid-life performed worse on memory tests and executive functions than their peers with no CVD-related risks. These differences persisted after accounting for age, gender, education and years since risk factors were measured.

These findings suggest that CVD risk factors as early as adolescence influence late-life brain health in African Americans. Efforts to promote heart and brain-healthy lifestyles must include not only middle-aged adults but also young adults and adolescents who may be especially susceptible to the negative impact of poor vascular health on the brain, researchers concluded. The National Institute on Aging (NIA) funded the study.

In another NIA-funded investigation presented virtually at the conference, a person’s body mass index (BMI) during higher early adulthood (ages 20 to 49) may be a risk factor for dementia in later life. Researchers say it is the first such study to target this issue.

Columbia University researchers looked at 5,104 older adults from two long-term studies: the Cardiovascular Health Study (CHS, n=2,909) and the Health, Aging and Body Composition Study (Health ABC, n=2,195). Of the total sample, 18% were Black and 56% were women. Using pooled data from four established cohorts spanning the course of adult life, the scientists estimated BMI beginning at age 20 for all older adults of CHS and Health ABC.

For women, dementia risk increased with higher early adulthood BMI. Compared to women with a healthy BMI in early adulthood, dementia risk was 1.8 times higher among those who were overweight, and 2.5 times higher among those who were obese. Analyses were adjusted for midlife and late-life BMI. No association was found between midlife BMI and dementia risk among women.

For men, the dementia risk was 2.5 times higher among those who were obese in early adulthood, 1.5 times higher if overweight in mid-life and 2.0 times higher if obese in mid-life, using models also adjusted for late-life BMI.

Among both women and men, dementia risk decreased with higher late-life BMI, which matches the conclusions of prior investigations.

“Research like this is important in addressing health inequities and providing resources that could make a positive impact on a person’s life,” said Maria C. Carrillo, Ph.D., chief science officer of the Alzheimer’s Association.

While this study only concluded an association, not causation, the researchers suggest that efforts aimed at reducing dementia risk may need to begin earlier in life, with a focus on obesity prevention and treatment. Journalists may want to explore:

  • What programs are available in their communities to educate teens and young adults on the importance of heart-healthy lifestyles, weight management and chronic disease prevention?
  • How has COVID-19 impacted local efforts targeted toward teens to encourage more exercise, eating healthy meals, and avoiding high-sugar, high-fat diets?
  • With many after-school programs closed or classes relegated to virtual learning, what are school districts doing to address health issues among those most at risk for developing CVD-related diseases?

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