In one of the largest studies to date, researchers linked loneliness to a 31-percent higher risk of developing dementia.
In 2023, U.S. Surgeon General Dr. Vivek Murthy sounded the alarm about the social isolation and loneliness epidemic. A recent poll found that three in ten adults say they experience loneliness at least once a week, while one in ten say they feel lonely every day. These feelings are associated with higher rates of depression, anxiety, and cardiovascular disease.
Scientists have also looked at the effects of social isolation and loneliness on cognitive health, separately. Social isolation refers to a lack of contact with others —but, some people are happy alone. For this camp, isolation doesn’t cause as many additional health problems. On the other hand, loneliness means that you aren’t spending as much time with others as you’d want to be — and research shows it could be more of a health risk.
While individual studies have found loneliness increases the risk of dementia, Martina Luchetti, a researcher at Florida State University, wanted to pool all the data together to get a clearer picture.
Their recent study, which looked at more than 600,000 individuals, was published in Nature Mental Health. The researchers found that loneliness increased the future risk of developing any type of dementia by about 31 percent, Alzheimer’s by 39 percent, vascular dementia by 73 percent, and cognitive impairment by 15 percent.
And, in contrast to previous studies that found loneliness poses a higher risk to men, this study didn’t find any difference in risk between men and women.
Htet Lin Tun, a PhD candidate at Monash University who wasn’t involved in the study, was unsurprised by the results. “The human brain is naturally social, and aside from loneliness, other aspects of social connection also play a role in dementia risk,” he told Being Patient. “These findings encourage us to look beyond traditional risk factors for dementia.”
Loneliness is seldom only associated with cognitive problems, so the risk of only developing cognitive decline is lower than the risk of developing dementia. Loneliness “also leads to increased stress, reduced social engagement, and other negative health outcomes that, over time, collectively elevate the risk of dementia,” Lin Tun noted.
Although this new study is one of the largest to date, Luchetti and her authors pointed to some important limitations in the underlying studies.
Many studies measured loneliness differently and tracked participants for different periods. The measures of cognitive impairment and dementia weren’t perfect either, as most studies didn’t use biomarkers to confirm an Alzheimer’s diagnosis.
Does loneliness cause dementia?
Loneliness and dementia are closely linked. But does loneliness cause dementia? Taking into account depression, social isolation, and other modifiable risk factors of dementia attenuated the risk of loneliness — but didn’t eliminate it. Another study published in September 2024 cast doubt on the idea that loneliness is the cause of the many diseases with which it’s associated.
Luchetti noted that most studies measure loneliness at a point in time: Just because someone is lonely at the start of the study doesn’t mean they remain lonely throughout the next 10 or 20 years.
Researchers are starting to hone in on how changes in loneliness over time affect risk, and even how overcoming feelings of loneliness can improve outcomes. One study has shown that people who’ve experienced persistent loneliness for years and who then recover from loneliness are even less likely to experience dementia compared to people who’ve never felt lonely at all.
Like many other research fields, most of the data looking at the links between loneliness and dementia come from high-income Western countries.
“It would be interesting to look at the consequences of loneliness in other cultural contexts,” Luchetti said.
Can socializing help to prevent dementia?
Even if it’s not the lone cause, the demonstrable connection between dementia risk and feeling lonely is strong enough that remedying social isolation has been named one of 12 key lifestyle factors that could help prevent 40 percent of all dementia cases.
“With the WHO recognising social (dis)connection as a global public health priority, we have a real opportunity to advance prevention efforts,” Lin Tun said. “Alternative care models, such as social prescribing, which focus on supporting the broader social determinants of health, are now gaining momentum for this reason.”
Kasley Killam, a social scientist who studies social health, shared guidance on overcoming lonliness with Being Patient earlier this year. According to Killam, finding people who share the same hobbies and volunteering about causes you care about are two great first steps toward meeting new people.
Beyond that, Killam said, social health should be prioritized — because human connection “is as important as exercise, nutrition, and sleep” to one’s physical health.
Seeking out new opportunities to meet people, Killam says, could help fight loneliness — which may have benefits to health overall.
I am definitely at risk for dementia, at age 67 having lived most of my life with a traumatic brain injury. Little was know about TBI when I was injured in 1970, I have been divorced and living alone for 20 years. There has been help from family and friends but I get lonely. Finding volunteer work has been helpful.
Hi Leslie, thank you for sharing your journey. Living with TBI can be challenging, but it’s great that volunteering helps you stay engaged. You might find this article helpful in understanding more about the link between Alzheimer’s and social interaction: https://www.beingpatient.com/alzheimers-and-social-interaction-heres-what-you-need-to-know/?utm_source=organic&utm_medium=social – take care.