How does heart health affect brain health?

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Updated data from the American Heart Association (AHA) emphasize the crucial link between heart and brain health. Image credit: Hiroshi Watanabe/Getty Images.
  • The 2022 Update of the AHA’s Heart Disease and Stroke Statistics emphasizes the bidirectional relationship between brain and heart health.
  • Globally, the number of dementia cases and deaths has increased alarmingly over the past 3 decades, more than heart disease.
  • Modifying risk factors for cardiovascular disease, such as smoking, diabetes, high blood pressure, obesity, and high cholesterol, may promote healthy aging and prevent cognitive decline.

Current evidence suggests a robust connection between brain health and cardiovascular health. Damage to the heart and blood vessels can increase a person’s risk of stroke and dementia.

A stroke occurs when a clot blocks blood flow or when a blood vessel ruptures in the brain. Strokes cause the death of brain tissue, sometimes resulting in a decline in memory and profound disability.

Additionally, the cumulative effect of multiple small silent strokes — which health experts call ministrokes — can cause vascular dementia. Dementia can have a detrimental impact on memory, cognitive functioning, and personality.

The AHA and the National Institutes of Health (NIH) update vital heart disease and stroke statistics annually. Their joint report highlights data related to important modifiable risk factors affecting cardiovascular health and outcomes associated with the quality of care, procedures, and economic costs for cardiovascular-related conditions.

The AHA Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee recently published “The Heart Disease and Stroke Statistics — 2022 Update: A Report From the American Heart Association” in the AHA’s peer-reviewed journal Circulation.

According to 2020 Global Burden of Disease (GBD) study data, the number of people worldwide with Alzheimer’s disease and related dementias increased at a greater rate than that of people with ischemic heart disease (IHD). From 1990 to 2020, the prevalence of Alzheimer’s disease and related dementias increased about 144% globally, compared with 120% for IHD.

The study reports more dramatic differences in Alzheimer’s disease and related dementias death rates during the same time frame, with an approximately 185% increase in Alzheimer’s disease and related dementias deaths and a 66% increase in IHD-related deaths.

A systematic analysis of the 2017 GBD study — the most recent data available — reports that 2.9 million people in the United States had an Alzheimer’s disease or Alzheimer’s disease and related dementias diagnosis.

It is the fourth most prevalent neurological disorder in the U.S., as well as the leading cause of death from neurological disease, surpassing stroke.

There is also a significant economic burden associated with Alzheimer’s disease and related dementias. Between 1996 and 2016, U.S. spending on dementias increased twofold, from about $39 billion to $79 billion.

Dr. Mitchell Elkind, the immediate past president of the AHA, a professor of neurology and epidemiology at Columbia University Vagelos College of Physicians and Surgeons, and attending neurologist at New York-Presbyterian/Columbia University Irving Medical Center in New York, spoke with Medical News Today about the new updates.

“Heart disease and brain disease share many of the same risk factors. Cardiovascular disease risk factors, or the health behaviors and conditions that can lead to heart attacks, include high blood pressure, diabetes, smoking, high cholesterol, and obesity,” he explained.

“For some time, we have known that these same risk factors also lead to strokes, which are injuries to the brain caused by blood vessel — i.e., vascular — disorders. What clinicians, epidemiologists, and other scientists have more recently found is that these same risk factors also contribute to other manifestations of brain disease, such as cognitive decline and dementia, that had not previously been recognized as [a] vascular disorder.”

– Dr. Mitchell Elkind

The 2022 Update highlights the effects of cardiovascular disease risk factors on cognitive dysfunction or dementia development.

In brief, a meta-analysis of 139 studies demonstrated that people with high blood pressure midlife were 55% more likely to develop impaired global cognition and about 20% more likely to experience impaired executive function, dementia, or Alzheimer’s disease.

Another meta-analysis of four studies found that people with heart failure were 80% more likely to develop dementia, while a meta-analysis of 14 studies found that females with diabetes had a 62% higher risk of developing dementia, and males had a 58% higher risk.

In terms of the risk of dementia linked to obesity, a meta-analysis of studies with up to 42 years of follow-up showed that people with midlife obesity had a 33% increased risk of developing dementia.

Smoking also remains an important risk factor. A meta-analysis of 37 studies demonstrated that people who smoked at the time had a 30% increased risk of dementia, a 40% higher risk of Alzheimer’s disease, and a 38% increased risk of vascular dementia.

The risk of cognitive dysfunction or dementia can vary depending on race, ethnicity, sex, education, occupation, and geography.

The 2022 Update highlights an analysis of 2016 Behavioral Risk Factor Surveillance System data that showed that Black adults were about three times more likely and Hispanic adults about four times more likely than white adults to need assistance with daily activities due to memory loss.

Additionally, Alzheimer’s disease and related dementias disproportionately affects females. According to GBD data from 2020, about 20 million males and 35 million females worldwide had a diagnosis of Alzheimer’s disease and related dementias, with a death rate of 1.28 million for females and 0.61 million for males.

Dr. Elkind commented:

“Because nearly half of all adults in the U.S. have elevated blood pressure, and 40% are obese, these data provide an inkling of what we can expect to see in the future as the population ages, and the impact of these risk factors begins to be felt. Recent data suggest that globally, dementia cases may triple over the next 3 decades, even as heart disease declines.”

Decreasing risk by modifying lifestyles and behavioral risk factors may help protect people from developing cardiovascular disease, stroke, and dementia. Dr. Elkind stated that a system-wide approach is necessary to achieve long-term behavioral change.

He explained: “Researchers are now testing technologies to see if they can improve our success rates with behavioral risk factors; some of these approaches involve moving the focus of care from the doctor’s office to the home and involving nonphysician providers in management to improve efficiency. For example, can in-home blood pressure monitoring with real-time connection to a doctor or nurse help improve blood pressure?”

Dr. Elkind also wondered: “Can we use nonclinical settings, such as barbershops, to reach Black men and women to detect high blood pressure and make changes in their lifestyles? […] These types of approaches may ultimately lead to bigger benefits than doctors prescribing specific medications or trying to convince individual patients to change their behaviors.”

Dr. Jason Tarpley — a stroke neurologist and director of the Stroke and Neurovascular Center for Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, CA — went on to comment, in an interview with MNT, that “the take-home message is that a lot of this is preventable” through a combination of a healthy diet, exercise, and medications.

He added: “The information age is helping people […] [P]atients know their cholesterol number, they know their LDL, they know their hemoglobin A1C — which is a long-term measurement of their blood sugar — and they know [their] blood pressures. I […] see that behaviors are changing, and I think that people are […] taking more their health into their own hands, and that’s really good.”