Roundup: Regular Exercise for Those with AFib Linked to Lower Stroke Risk, Living Longer; and More News

Even Light Exercise May Help People With AFib Live Longer, Lower Stroke Risk, Study Finds

Regular physical activity may help lower the risk of stroke and early death for people living with atrial fibrillation (AFib), according to a new study published in the Journal of the American Heart Association. Researchers found that even small amounts of exercise were associated with health benefits, while the greatest benefits were seen among people who were the most active.

The findings suggest that staying physically active is important for adults whether or not they have AFib.

What is Atrial Fibrillation?

AFib is the most common type of irregular heart rhythm. It occurs when the heart’s two upper chambers, called the atria, beat in a fast, disorganized way instead of contracting normally. This can allow blood to pool inside the heart, increasing the risk of blood clots, stroke and other heart-related complications.

Researchers estimate that more than 10 million adults in the United States have AFib.

What the Study Found

Researchers followed more than 87,000 adults in Norway for about 15 years, including more than 6,500 people with AFib. Participants reported how often they exercised, how long they exercised and how hard they exercised.

Compared with people who were inactive, those who reported low, moderate or high levels of physical activity had a 9 percent, 19 percent and 18 percent lower risk of stroke, respectively. They also had an 11 percent, 18 percent and 22 percent lower risk of death from any cause.

The benefits were nearly identical for people with and without AFib. Among participants with AFib, being physically active was also linked to living an average of six months to just over one year longer than those who were inactive.

Researchers said the results reinforce that even modest amounts of movement are better than none.

Why the Findings Matter

People with AFib are often less physically active than the general population, sometimes because they worry exercise could trigger symptoms. However, the study suggests that regular physical activity may be an important part of maintaining health for people living with the condition.

The American Heart Association recommends adults get at least 150 minutes of moderate-intensity aerobic exercise, such as brisk walking, each week or 75 minutes of vigorous activity, such as running. Adults should also perform muscle-strengthening activities at least twice a week.

Important limitations

The study shows an association between physical activity and better health outcomes, but it does not prove that exercise directly caused the lower risk. People who are more active often have other healthy habits that may also contribute to longer life and lower stroke risk.

In addition, participants reported their own activity levels, which may not have been completely accurate.

Still, researchers say the findings add to growing evidence that staying active—even at low levels—can provide meaningful health benefits for people with AFib and the general population.

Avoiding These 3 Vascular Risk Factors in Midlife May Delay Dementia Risk for Years Later, Study Finds

Taking care of your heart in midlife may also help protect your brain for years to come, according to a new U.S. study. Researchers found that adults with healthy blood vessels at age 55 lived significantly longer without dementia than those with multiple vascular risk factors such as high blood pressure, diabetes and smoking.

The findings highlight how managing common health conditions in middle age may help preserve both cardiovascular and cognitive health as people age.

What the Study Found

Researchers analyzed data from more than 12,400 adults participating in the long-running Atherosclerosis Risk in Communities (ARIC) Study. Participants were free of dementia at age 55 and were followed for a median of 26 years.

The researchers looked at three major vascular risk factors measured during midlife:

• High blood pressure (hypertension)
• Diabetes
• Current smoking

People were grouped based on whether they had zero, one, two or three of these risk factors.

Adults with no vascular risk factors were expected to live about 30 years free of dementia, from age 55 to 95. In contrast, those with all three risk factors averaged 17.5 dementia-free years—a difference of approximately 12.6 years.

Why the Difference Matters

The study found that people with more vascular risk factors were much more likely to develop dementia. Dementia is a group of conditions that gradually impair memory, thinking and the ability to perform everyday activities.

However, the highest-risk group was also much more likely to die from other causes before developing dementia. Researchers call this competing mortality, meaning death from another cause occurs before dementia has a chance to develop. As a result, although dementia occurred earlier among higher-risk participants, fewer survived long enough to be diagnosed by age 95.

Differences Among Groups

The study also found differences among demographic groups.

Women generally lived longer without dementia than men, even when they had multiple vascular risk factors. Among participants with all three risk factors, women averaged 18.1 dementia-free years compared with 16.6 years for men.

Black participants had fewer dementia-free years than White participants, reflecting longstanding differences in cardiovascular health and other factors that influence healthy aging.

A Practical Message for Healthy Aging

The researchers say expressing risk as "years of dementia-free life" may be easier for patients to understand than percentages or statistical risk. Instead of focusing only on the chance of developing dementia, the findings show how everyday health habits may influence how many years people remain cognitively healthy.

While this observational study cannot prove that controlling blood pressure, diabetes or smoking directly prevents dementia, it adds to growing evidence that maintaining good vascular health in midlife is an important part of healthy aging. Along with regular physical activity, a balanced diet, not smoking and managing chronic conditions, these steps may help support both heart and brain health over the long term.

NIH Lab-Grown ‘Cancer Models’ Could Help Speed Development of Precision Treatments

A large new collection of laboratory-grown human cancer models could help scientists better understand how tumors behave, why some cancers resist treatment and which therapies may work best for particular patients, according to a news release from the National Institutes of Health (NIH).

The NIH-funded Human Cancer Models Initiative (HCMI) has created an internationally available resource representing 25 types of cancer. Researchers say the models closely preserve important biological characteristics of the patients’ original tumors, making them potentially valuable tools for developing and testing cancer treatments.

Creating more realistic models of cancer

Patient-derived cancer models are created from tumor tissue donated by people with cancer and grown under controlled laboratory conditions. Scientists use these models to study how cancers develop and respond to treatments without experimenting directly on patients.

The HCMI collection includes 665 advanced laboratory models developed using tissue and data from a pool of 2,780 donors. The collection covers common cancer subtypes and many of the genetic changes known to drive them. It also includes 153 models of rare cancers.

Some models are grown as organoids, three-dimensional clusters of cells designed to reproduce important characteristics of actual organs and tumors. Others include neurospheres, clusters of brain cancer cells with characteristics similar to neural stem cells.

Models closely resemble patients’ tumors

A key question is whether cancer cells grown in a laboratory remain similar enough to the original tumor to provide useful information.

HCMI researchers compared 421 patient tumors with models derived from them. They reported 97.8 percent agreement in genetic alterations and 95 percent agreement in epigenetic characteristics. Epigenetics refers to biological changes that affect whether genes are switched on or off without changing the underlying DNA sequence.

The researchers also found 92 percent similarity in RNA expression. RNA carries instructions from genes that help control cell activity, so these patterns can provide clues about a tumor’s origin and behavior.

Importantly, the similarities persisted even after the models were grown for extended periods in the laboratory.

Studying why cancer treatments stop working

Researchers could also use the models to investigate treatment resistance, which occurs when cancer fails to respond to a therapy or begins growing again after initially responding.

For example, models of glioblastoma, an aggressive type of brain cancer, showed several genetic characteristics associated with resistance to temozolomide, a chemotherapy drug commonly used to treat the disease.

Understanding these changes could help researchers identify weaknesses in resistant cancers and develop strategies to target them.