The same factors that raise the risk for heart disease also impact brain disease, including stroke, Alzheimer’s disease, and other dementias. “Heart disease is the leading cause of death and disability worldwide,” says Alice H. Lichtenstein, DSc, senior scientist and director of the Cardiovascular Nutrition Laboratory at the Human Nutrition Research Center on Aging and executive editor of Tufts Health & Nutrition Letter. “As the mean age of the world’s population is increasing, it’s not surprising the prevalence of stroke and dementias is on the rise.”
Stroke was the fifth leading cause of death overall in 2020, and many more people suffered disabilities from stroke. But deaths and disabilities from Alzheimer’s disease and other dementias combined outrank those attributed to strokes. In recognition of this, the American Heart Association’s 2022 Heart Disease and Stroke Statistics annual report includes a chapter on brain health for the first time. We talked to a member of the report’s writing committee, Mitchell S.V. Elkind, MD, MS, FAHA, to get the latest on the relationship between cardiovascular health and brain health—and what you can do to bolster both. Dr. Elkind is chief clinical science officer of the American Heart Association and a past volunteer president of the Association (2020-21). Until recently he was professor of neurology and epidemiology and chief of the Division of Neurology Clinical Outcomes Research and Population Sciences at Columbia University in New York.
Health & Nutrition Letter (HNL): How does vascular health impact brain health?
Dr. Elkind: Blood vessels supply oxygen and nutrients to the brain, so problems affecting those blood vessels or the heart itself can impair brain health. Accumulating evidence suggests cardiovascular risk factors lead to cognitive decline and dementia. Similarly, behaviors that promote vascular and heart health, such as physical activity and a healthy diet, also promote brain health and healthy aging—in effect, what is good for the heart and blood vessels is good for the brain.
HNL: What are vascular disease risk factors?
Dr. Elkind: Vascular risk factors include both genetic and behavioral factors. Genetic factors are important because they help identify those people at greatest risk. Behavioral factors are important because they can be modified. High blood pressure, high cholesterol, smoking, diabetes, excessive alcohol consumption, and obesity are among the most important factors.
HNL: What types of vascular or cardiovascular disease have been associated with higher risk of brain disease?
Dr. Elkind: Hypertension, or high blood pressure, is the most important risk factor for adverse brain health. Even mild elevations in blood pressure increase the risk of stroke and dementia compared to lower levels. High blood pressure in midlife, for example, is associated with a fivefold increase in the risk of late-life cognitive decline, and a doubling in the risk of dementia. Heart diseases themselves also lead to strokes and dementia: Atrial fibrillation (an irregular rhythm of the heart) increases the risk of stroke fivefold. Heart failure and atrial fibrillation both increase the risk of dementia by 40 to 80 percent.
Other vascular risk factors are also important: obesity is associated with a tripling in risk of dementia, and smoking is associated with a 40 to 50 percent increase in dementia risk.
HNL: How can people improve their vascular (and brain) health?
Dr. Elkind: Controlling blood pressure, blood sugar, cholesterol, and weight are essential. People should also avoid or quit smoking, and eat a healthy, Mediterranean-style dietary pattern.
Physical activity is crucial, and it is related to the other risk factors. Physical activity helps to reduce blood pressure and weight. Reducing sedentary behavior is also important, even apart from getting physical activity. So, if a person exercises daily but then spends the rest of the day seated at a desk or computer, that may negate the benefits of the exercise. It is important to work healthy behaviors, like getting up to walk every hour, into a daily routine. In fact, it probably doesn’t require a lot of exercise to see a benefit from physical activity. Walking thirty minutes a day reduces risk of stroke and reduces cognitive decline and dementia risk, and this is something that even older people can do.
Another way to improve vascular health and brain function is to get enough sleep. The American Heart Association has recently revised its recommendations for healthy lifestyle to include getting a sufficient amount of sleep every night: seven to nine hours. (See Eight Essentials for Heart Health on page 4.)
HNL: Is there anything else you want our readers to know about the connection between vascular health and brain health?
Dr. Elkind: The recognition that cardiovascular risk factors contribute to brain diseases reflects an awareness that vascular problems contribute to brain disorders, such as Alzheimer’s disease, that have long been considered exclusively degenerative. Most people who die with dementia are found at autopsy to have evidence of more than one brain disorder: the plaques and tangles of Alzheimer’s disease, the multiple strokes seen in vascular dementia, and other problems. Gradual blocking of brain vessels may thus worsen neurodegeneration. So healthy blood vessels may decrease the brain damage associated with brain aging from other causes as well.
The heart pumps blood through the vascular system to every part of the body. Problems with the heart or vascular system can impact the brain.