Association Found Between Social Isolation and Reduced Brain Volume in Elderly Individuals

A higher level of social contact is associated with a higher brain volume in adults over 65, according to a new study.

In other words, spending time with family and friends is more than just enjoyable, it’s healthy.

On the other hand, more frequent social isolation was associated with smaller brain volume in seniors, particularly in regions of the brain typically associated with cognitive function.

The study was published on July 12 in Neurology, the medical journal of the American Academy of Neurology.

The brains of those who socialized the least, on average, took up 67.3% of the total cranial volume. Those who socialized the most had an average brain volume of 67.8%.

Researchers emphasized that the study doesn’t prove that a lack of social engagement can cause a lower brain volume, or vice versa. This is partly because the study did not follow participants as they aged.

“The authors do not show any dynamic measures showing greater selective ‘shrinkage’ from a baseline. They merely show that some regions show different volumes,” Michael Lee, MD, professor and director of neuro-ophthalmology at the University of Minnesota Medical School, told Health.

Loneliness is already a huge concern in the United States. A correlation between social contact and brain volume adds another layer to this concern—a shrinking (atrophy) of the brain can cause neurological issues such as dementia, difficulty communicating, memory loss, or disorientation.

“Social isolation is a growing problem for older adults,” study author Toshiharu Ninomiya, MD, PhD, said in a press release. “Providing support for people to help them start and maintain their connections to others may be beneficial for preventing brain atrophy and the development of dementia.”

In order to find an association between social contact and brain volume, the study authors looked at almost 9,000 people in Japan over the age of 65. The average participant age was 73, and going into the study, none of them had dementia.

Study participants had an MRI done of their brains, and were asked one question about their social behavior—people answered that they were in contact with relatives or friends either every day, several times a week, several times a month, or seldom.

In addition to finding a lower general brain volume amongst those who seldom socialized, that group also had lower volumes in specific regions of the brain that related to cognition—the temporal lobe, occipital lobe, cingulum, hippocampus, and amygdala.

People who were more socially isolated also had more white matter lesions—spots on the brain that can be indicative of issues such as cardiovascular disease or dementia.

Though the data clearly showed differences in people’s social behaviors and lower brain volume, determining how people ended up with low brain volume is a more difficult question to answer.

The study is a snapshot of a moment in time, so it’s hard to know how participants’ brains changed over the course of a lifetime, or what effect someone’s social life had on their brain.

It is possible, however, that those with lower brain volume once had a higher volume in line with the more social participants—this would mean that their brains would’ve shrunk.

This in and of itself isn’t necessarily as shocking as it may sound, Peter Whitehouse, MD, PhD, professor of neurology at Case Western Reserve University, told Health.

As someone ages, their brain begins to slowly and slightly lose volume, he said, and it may not have significant negative effects.

Besides just general aging, loss of brain volume has been associated with everything from traumatic brain injuries to drinking just a couple of glasses of alcohol—the symptoms can vary just as widely.

Though it’s hypothesized that study participants with lower brain volume experienced brain shrinkage, more research needs to be done.

Studies should examine brain volume and social contact over years, said Lee, to see if social behavior affects the degree to which the brain’s volume changes. It would also be helpful to know if social contact can be used as an intervention against brain atrophy, he explained.

Additionally, more could be gleaned from insight into people’s social habits over the course of a lifetime, Whitehouse said. A person who’s been isolated their whole life may have a different brain volume than someone who only became isolated in old age.

A shrinking brain can be related to cognitive impairment issues, such as dementia, but it’s also too soon to say whether a lack of social engagement causes these issues.

“It could be that the people with early dementia just decide not to socialize more, or the spouse keeps them in,” Whitehouse said. “So it could be that the dementia causes the social isolation.”

Though the group was deemed dementia-free when the study started, apathy—a lack of interest in activities—is a symptom of dementia. In the earliest stages of brain changes, people may feel less desire to spend time with others, the study authors explained, and the low of brain volume could be driving social isolation.

Depression is another variable that’s been associated with a loss of brain volume.

“It could be that the really important variable there is depression, and not going out and seeing people [is] related to depression,” Whitehouse said. “Depression was what could also be causing shrinkage, and ultimately, possibly a cognitive impairment.”

Study authors wrote that depression symptoms partly mediated the link between social isolation and brain atrophy, but depression wasn’t the driver in all cases.

Instead, the authors hypothesized that other health issues could be to blame.

People who were more socially isolated were more likely to smoke, be inactive, have diabetes, and have high blood pressure, the study found. These types of cardiovascular risk factors are also associated with brain atrophy. 

The study didn’t establish that lack of social contact causes the loss of brain volume or accompanying dementia, so it can be difficult to definitively guide people in avoiding cognition issues as they age.

However, there’s plenty of research that echoes the overarching connection between brain and bodily health.

“Our relationship to the external world has a great impact on our ‘hormonal’ balance, immune system, our activity, and our lifestyle,” said Lee. “For example, social contact can have profound modulatory impact on how much stress we feel. We know that excess stress hormones can negatively impact brain function.”

Eating, sleeping, exercising, relaxing, and building relationships with people can all impact the way that the human body functions.

How a person chooses to keep their mind sharp can vary. Whitehouse recommends dance as a good option for people as they age—it provides space to engage the mind and body, as well as an opportunity for social interaction, he said.

Another study released on Friday found that certain types of engaging leisure activities—such as writing letters, using the computer, playing games, or doing puzzles—may also lower dementia risk. Interestingly, authors didn’t find any correlation between dementia risk and interpersonal or social activities.

Some evidence suggests that the Mediterranean diet may help protect against cognitive impairment. But Whitehouse said any nutrient-rich diet can be helpful. Studies also show that exercise can have a positive impact on cognitive function and well-being.

“In general, what’s good for your brain is what’s good for your heart, and vice versa,” Whitehouse said.