Physical activity and healthy blood sugar levels during midlife may be linked to a significantly slower decline in thinking abilities later in life, according to new research from UT Health San Antonio, the academic health center at the University of Texas at San Antonio. The findings suggest that exercise may be especially important for Hispanic adults.
Scientists already know that cardiovascular problems in midlife can increase the risk of cognitive decline and dementia. This study is one of the first to investigate how specific cardiovascular health factors may relate to cognitive aging in different ethnic groups.
The researchers analyzed 402 people from San Antonio. Of the participants, 52% were Hispanic and the remainder were non-Hispanic white. The average age was 57.9 years and 58.5% were women.
Findings varied by ethnicity. Physical activity was particularly associated with slower cognitive decline among Hispanic participants, while lower fasting blood glucose levels were associated with slower cognitive decline among non-Hispanic white participants.
“By improving cardiovascular health through modifiable lifestyle changes, there is potential to significantly alleviate the public health burden of Alzheimer’s disease and other dementias, particularly in high-risk populations,” said Claudia Satizabal, PhD, associate professor in the Department of Population Health Sciences at UT Health San Antonio and its Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, where she directs the Population Neuroscience Core.
Satizabal is co-senior author of the study with Chen-Pin Wang, PhD, research associate professor in the Department of Population Health Sciences. The research, titled “Longitudinal association between midlife cardiovascular health and cognitive change in a biethnic cohort,” was published July 23 by Alzheimer’s and dementia: behavior and socioeconomics of aging.
All study authors are affiliated with the Glenn Biggs Institute or the University of Texas Rio Grande Valley.
Cardiovascular health and risk of dementia
As people around the world live longer and the proportion of older adults grows, age-related conditions such as dementia are becoming increasingly common. The study notes that 6.7 million people in the United States currently suffer from Alzheimer’s disease.
At the same time, research increasingly suggests that many risk factors for cognitive decline and dementia can be modified. Recent estimates indicate that almost 40% of Alzheimer’s cases may be related to these factors. Cardiovascular health, in particular, has become an important influence on how the brain ages.
A widely used approach to measuring cardiovascular health is the American Heart Association’s Life’s Simple 7 (LS7) framework. It includes three behavioral factors (healthy diet, non-smoking, and physical activity) and four health factors (blood pressure, body mass index, total cholesterol, and fasting blood glucose). According to the study, LS7 provides an overall measure of cardiovascular health and has also been proposed as a way to support better brain health.
Previous research has found that greater adherence to LS7 is associated with better cognitive performance, healthier brains, and a lower risk of dementia. However, these relationships do not appear to be identical in different populations.
Hispanic older adults face a disproportionate burden of Alzheimer’s disease and related dementias. About 14% of Hispanic adults age 65 and older have Alzheimer’s, compared with 10% of non-Hispanic white older adults. Mexican Americans, who make up the largest Hispanic population in the United States, also have particularly high rates of diabetes, obesity and dyslipidemia, conditions that can increase the risk of dementia.
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Despite these disparities, Hispanic populations remain underrepresented in Alzheimer’s research. The researchers note that this lack of representation makes it more difficult to understand how dementia risk develops over time and to identify prevention strategies that can work effectively for everyone.
To help address that gap, the UT Health San Antonio team investigated the relationship between midlife cardiovascular health, measured through LS7 scores, and subsequent cognitive decline among Mexican American and non-Hispanic white older adults. Participants had previously participated in the San Antonio Heart Study (SAHS) and the San Antonio Longitudinal Study of Aging (SALSA).
The SAHS was a landmark long-term project led by UT Health San Antonio to investigate the causes of type 2 diabetes and heart disease. Conducted from 1979 to the 2000s, the project followed more than 5,000 people to better understand why certain ethnic populations experience greater health risks.
SALSA later emerged from that work. Also conducted by UT Health San Antonio, it became a major long-term observational study focused on chronic diseases, healthy aging, and the process by which older adults develop disabilities. Its participants had previously been enrolled in the SAHS.
“Importantly, the inclusion of both ethnic groups from the same population of origin and geographic setting allows for direct comparison within a shared contextual framework and strengthens our ability to identify disparities in cognitive aging and its cardiovascular correlates,” the new study notes.
Tracking cognitive changes over time
For the new analysis, the researchers assessed cardiovascular health among SAHS participants who later enrolled in SALSA, using their LS7 scores.
Cognitive ability was measured up to four times with the Mini Mental State Examination, an established 11-question screening test that assesses memory, attention, and thinking skills.
The team also used generalized estimating equation modeling to examine how cardiovascular factors were related to changes in cognition. Statistical models took into account age, sex, income, and education.
Additionally, the researchers conducted sensitivity analyzes to assess attrition bias. These additional statistical checks were designed to determine whether people who dropped out of the study could have skewed the final results.
Exercise and blood sugar show different links
The analysis found that engaging in any physical activity, rather than leading a sedentary lifestyle, was particularly associated with slower cognitive decline among Mexican Americans.
Fasting glucose also emerged as an important factor. This measurement reflects the amount of sugar in the blood after fasting for eight to 12 hours. Among non-Hispanic white participants, fasting glucose readings of 126 milligrams per deciliter or less were associated with a slower rate of cognitive decline.
“Our findings suggest that engaging in any level of physical activity and potentially maintaining optimal fasting blood glucose levels in midlife are associated with a significantly slower rate of cognitive decline in old age,” said Janette Vázquez, PhD, first author of the study and currently a senior postdoctoral fellow at the Glenn Biggs Institute. But because the results differed by ethnic group, more research is needed in larger samples to replicate the differences, he said.
The findings suggest that cardiovascular health during midlife could influence cognitive aging many years later, but they also indicate that the most important factors may not be the same for all populations.
“Longitudinally exploring cardiovascular health across the lifespan, rather than assessing it at a single point in time, could also provide more information about the trajectory of phenotypes that contribute to cognitive decline by ethnicity,” Vázquez said.
Study participants are now invited to join the San Antonio Heart and Mind Study (SAHMS) at the Glenn Biggs Institute. Researchers hope the ongoing project will generate additional discoveries by collecting cutting-edge brain imaging and other neurological data.