Good heart health in middle age may preserve brain function among Black women as they age

"Take care of your heart, and it will benefit your brain," said study lead author Imke Janssen, Ph.D., a professor of family and preventive medicine at Rush University Medical Center in Chicago. "Better cardiovascular health in women in their 40s is important to prevent later-life Alzheimer's disease, dementia and to maintain independent living."

Previous research has linked heart health to a lower risk of cognitive decline. This decline may begin years before the onset of dementia, Janssen explained. Questions that need to be answered include understanding when the cognitive benefits of heart health begin, whether they occur among people of different races and whether they affect different types of brain function including reasoning.

In this study, researchers compared key heart health metrics, known as the American Heart Associations' Life's Essential 8, among middle-aged Black and white women to cognitive testing conducted on the women every one to two years over a 20-year period.

Life's Essential 8^TM includes objectively measured weight, blood pressure, glucose, and cholesterol, as well as self-reported health behaviors such as eating healthy foods, being physically active, not smoking and getting enough sleep.

The cognitive tests assessed processing speed and working memory. Processing speed is the pace at which the brain has accurate recognition of visual and verbal information and is necessary for daily activities such as driving. In this study, cognitive processing speed was assessed as quickly and accurately recognizing sets of numbers, objects, pictures or patterns. Working memory is the ability to remember and use small pieces of information for daily tasks, including remembering names and doing math.

The study found differences in cognitive decline by race only in processing speed, not in working memory. Specifically:

• Black women with lower heart health, based on the Life's Essential 8 metrics, had a 10% decrease in processing speed over 20 years. Their scores were worse for all eight risk factors for heart disease, especially blood pressure and smoking.
• In contrast, Black women with good heart health showed little decline in mental processing during the 20-year study.
• Among white women with poorer heart health, processing speed did not decline.
• Heart health did not affect working memory for Black or white women.

"We were surprised that we did not find results like those of past studies, which showed cognitive decline in Black and white men and women, and found cardiovascular health to be more important for white adults rather than people in Black subgroups," Janssen said. "We think these differences are due to the younger age of our participants, who began cognitive testing in their mid-40s, whereas previous studies started with adults about 10 to 20 years older. The next step is a clinical trial to confirm whether optimizing heart health in Black women at midlife may slow cognitive aging, maximize independence and reduce racial inequities in dementia risk."

Several limitations may have affected the study's results. The study included women from a single study site and relied on self-reported measures of heart health, which may have been inaccurate. In addition, the study did not include measures that may account for racial differences in access to health care or the potential impact of structural racism on Black participants.

Study background and details:

• The study included 363 Black and 402 white women from the Chicago site of the Study of Women's Health Across the Nation (SWAN).
• The Chicago SWAN group started cognitive testing in 1997, when the women were between 42 and 52 years old. Cognitive testing continued every one to two years through 2017.
• The analytic sample consisted of 765 women who provided 5,079 cognitive processing speed and 4,933 working memory assessments over the 20-year period.
• Heart health based on Life's Essential 8 was assessed at time of enrollment only.