Twin study shows what's good for the heart is good for the brain
Relationship between CV risk and cognitive decline
October 21, 2019
Science Daily/Emory Health Sciences
Researchers are giving us double the reasons to pay attention to our cardiovascular health - showing in a recent study that good heart health can equal good brain health.
Emory University researchers are giving us double the reasons to pay attention to our cardiovascular health -- showing in a recently published study in the Journal of Alzheimer's Disease that good heart health can equal good brain health.
The American Heart Association defines ideal cardiovascular health (CVH) across seven modifiable risk factors (blood sugar, serum cholesterol, blood pressure, body mass index, physical activity, diet and cigarette smoking). Higher CVH scores point to better heart health and lower risk for cardiovascular disease (CVD).
Prior studies have indicated that ideal CVH also benefits brain health and cognitive aging. However, it was unclear how genes and/or environment played into the relationship between cardiovascular risk factors and cognitive decline.
By studying pairs of twin brothers from the Vietnam Era Twin (VET) registry, researchers were able to observe the relationship between CVH and cognitive performance across all participants that may be explained by genetics and/or exposures or behaviors that are shared by members of the same family.
Twin studies are a special type of epidemiological study that allow researchers to examine the overall role of genes and environment in a behavioral trait or disorder. Identical twins share 100 percent of their genetic material, while fraternal twins share on average 50 percent of genetic material. For a given trait or medical condition, any excess similarity between identical twins compared with fraternal twins, is likely suggestive of genes rather than environment. Twin studies can serve to differentiate between "nature vs. nurture."
"Our study across the entire sample of twins confirmed that better CVH is associated with better cognitive health in several domains," says senior author Viola Vaccarino, MD, PhD, Wilton Looney Professor of Cardiovascular Research, Rollins School of Public Health, and professor, division of cardiology, Emory University School of Medicine. "The analyses further suggested that familial factors shared by the twins explain a large part of the association and thus could be important for both cardiovascular and brain health."
To determine whether these familial factors were genetically or environmentally driven, researchers further stratified the within-pair analysis to determine whether the relationship between CVH and cognitive function was different between identical and fraternal twins.
The within-pair association was similar in identical and fraternal twins. Therefore familial factors, such as early family environment, early socioeconomic status and education, and parenting -- rather than genetics -- may be important precursors of both cardiovascular and brain health -- thus explaining some of the association between CVH and cognition.
"Improving population-level CVH scores, which are extremely low in the United States, has the potential to reduce the burden of dementia along with heart disease," says study co-author Ambar Kulshreshtha, MD, PhD, assistant professor of family and preventive medicine, Emory University School of Medicine. "Because CVH factors are modifiable, prevention of cardiovascular risk factors and promotion of a healthy lifestyle beginning early in life should achieve the best results for promoting not only cardiovascular health, but also cognitive health."
https://www.sciencedaily.com/releases/2019/10/191021135040.htm
Running, cardio activities in young adulthood preserves thinking in middle age
April 2, 2014
Science Daily/American Academy of Neurology (AAN)
Young adults who run or participate in other cardio fitness activities may preserve their memory and thinking skills in middle age, according to a new study published in the April 2, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. Middle age was defined as ages 43 to 55.
"Many studies show the benefits to the brain of good heart health," said study author David R. Jacobs, Jr, PhD, with the University of Minnesota in Minneapolis. "This is one more important study that should remind young adults of the brain health benefits of cardio fitness activities such as running, swimming, biking or cardio fitness classes."
Cardiorespiratory fitness is a measure of how well your body transports oxygen to your muscles, and how well your muscles are able to absorb the oxygen during exercise.
For the study, 2,747 healthy people with an average age of 25 underwent treadmill tests the first year of the study and then again 20 years later. Cognitive tests taken 25 years after the start of the study measured verbal memory, psychomotor speed (the relationship between thinking skills and physical movement) and executive function.
For the treadmill test, which was similar to a cardiovascular stress test, participants walked or ran as the speed and incline increased until they could not continue or had symptoms such as shortness of breath. At the first test, participants lasted an average of 10 minutes on the treadmill. Twenty years later, that number decreased by an average of 2.9 minutes. For every additional minute people completed on the treadmill at the first test, they recalled 0.12 more words correctly on the memory test of 15 words and correctly replaced 0.92 more numbers with meaningless symbols in the test of psychomotor speed 25 years later, even after adjusting for other factors such as smoking, diabetes and high cholesterol.
People who had smaller decreases in their time completed on the treadmill test 20 years later were more likely to perform better on the executive function test than those who had bigger decreases. Specifically, they were better able to correctly state ink color (for example, for the word "yellow" written in green ink, the correct answer was "green").
"These changes were significant, and while they may be modest, they were larger than the effect from one year of aging," Jacobs said. "Other studies in older individuals have shown that these tests are among the strongest predictors of developing dementia in the future. One study showed that every additional word remembered on the memory test was associated with an 18-percent decrease in the risk of developing dementia after 10 years."
"These findings are likely to help us earlier identify and consequently prevent or treat those at high risk of developing dementia," Jacobs said.
http://www.sciencedaily.com/releases/2014/04/140402162333.htm