Keeping the Heart Healthy Could Help Lower Dementia Risk

Getting older can be unsettling for many people. Beyond the possibility of losing some abilities or facing new limitations, there is also the fear of losing the memories that define who they are. Still, there may be encouraging news: despite concerns about a future Alzheimer’s surge, dementia rates appear to be falling in Europe and the United States, by as much as 13% per decade over the past 30 years, according to research published in Neurology. The study’s authors, from the Alzheimer’s Cohorts Consortium, believe they may have an explanation.

Dementia Is Not an Expected Part of Aging

The consortium analyzed data from seven studies that tracked more than 49,000 people older than 65 for at least 15 years. In total, 4,253 participants developed dementia. Researchers reviewed in-person exams, genetic information, brain scans, and cardiovascular risk factors before drawing conclusions about possible causes. The National Institute on Aging defines dementia as “the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that it interferes with a person's daily life and activities.” Although it becomes more common with age, the NIA stresses that dementia is “not a normal part of aging.”

So why have rates declined? “When we tried to explain this, the natural thing to think about is cardiovascular risk factors,” said Albert Hofman, MD, PhD, in an interview with Medical Daily. Hofman, one of the study authors, is chair of the department of epidemiology at the Harvard T.H. Chan School of Public Health in Boston. Factors such as high blood pressure, high cholesterol, and smoking may be contributing to the reduction in dementia cases, even if the connection is not immediately obvious.

Protecting the Brain by Protecting the Heart

Improvements in modern medicine, along with lower smoking rates, have helped cardiovascular health. People who follow medical advice and make lifestyle changes such as quitting smoking, exercising, and eating a healthy diet may better control blood pressure and cholesterol. That may also support brain health, since these steps help preserve the fragile blood vessels in the head.

A research letter published in 2017 in the Journal of the American Medical Association, Cardiology, reported that average total cholesterol fell from 204 mg/dL in 1999/2000 to 189 mg/dL in 2013/2014, reflecting a steady decline. The Centers for Disease Control and Prevention has also said that current smoking dropped from 20.9% in 2005 to 13.7% in 2018, while the share of former smokers who have quit increased. In some ways, that means the population is becoming healthier overall.

But controlling cholesterol and blood pressure is only part of the story. Hofman said the issue is not just the numbers themselves, but also how much blood pressure fluctuates. “There is always variability in blood pressure but some people have higher and others have lower,” he said. Although blood pressure is linked to lifestyle factors such as body mass index, that variability has not been studied as thoroughly. “The relationship between lifestyle factors and variability is still largely unexplored although it is a focus of current research,” Hofman added.

What Can People Do?

Researchers do not know exactly when people should begin paying attention to dementia risk factors, but the earlier the better. “It’s never too late,” Hofman said. “You can always improve, but the most effective way is to do it as early as possible.” He said dementia risk may be reduced by “treating [cardiovascular] risk factors but also looking at preventative measures, to prevent hypertension and high cholesterol.”

Are women at greater risk? Many people assume so, but the study suggests that is not the case. “Incidence, the risk, of new cases is very similar for men and women,” Hofman said. “Women live longer, so there are more women living with dementia than men.”

The Bottom Line

Dementia rates are declining, and women do not appear to face a higher risk than men. Even so, protecting blood vessels may help protect the brain. Monitoring blood pressure and cholesterol, and talking with a doctor about any needed lifestyle changes, can support overall health. Researchers are still working to better understand blood pressure variability and what else may help keep the brain healthy for as long as possible.