Loneliness can increase the risk for dementia, a large study shows

Feeling lonely increased risk for all-cause dementia by 31 percent and cognitive impairment by 15 percent.

The Washington Post
Meeri Kim
November 14, 2024 

Loneliness is a common — some would even say, universal — human experience.

It can range from fleeting feelings of social isolation that may not have a negative effect on our health to persistent, chronic loneliness that is associated with many damaging health conditions.

U.S. Surgeon General Vivek H. Murthy, who last year issued a public health advisory on loneliness, said the risk for premature death posed by chronic loneliness is akin to smoking up to 15 cigarettes a day. Poor or insufficient social connection has been associated with increased risk for heart disease, stroke, anxiety and depression.

Now, a meta-analysis, using longitudinal data from over 600,000 people, has found that loneliness increases the risk for dementia because of any cause, including Alzheimer’s disease. The results also reveal that loneliness is associated with cognitive impairment, an early stage of cognitive decline that may precede the onset of dementia.

“Loneliness is relevant to cognition in general, across the dementia spectrum,” said study author Martina Luchetti, an assistant professor of behavioral sciences and social medicine at Florida State University. “We know that dementia is a syndrome that starts decades before a diagnosis, and loneliness is associated with multiple cognitive outcomes besides the endpoint of dementia.”

Loneliness increases risk of dementia, cognitive impairment

The study, published in the journal Nature Mental Health in October, pooled 608,561 individuals across 21 population cohorts in the United States, the United Kingdom, China, Australia and other countries.

Loneliness was measured by asking participants questions such as “How often do you feel lonely?” or “How often do you feel that you lack companionship?” rated from never to always on a multiple-point scale. To assess cognitive status, studies either used a dementia diagnosis or performance on cognitive tests.

The pooled estimates indicated that feeling lonely increased risk for all-cause dementia by 31 percent and cognitive impairment by 15 percent. The associations persisted even after controlling for depressive symptoms, social isolation and dementia risk factors such as diabetes, hypertension and obesity. The effect size of loneliness on dementia risk, according to the researchers, is comparable to that of sedentary behavior or smoking.

“We may not yet have a cure for Alzheimer’s disease and other types of dementia, but we do have a cure for loneliness,” said Joel Salinas, a clinical assistant professor of neurology at NYU Langone Health and chief medical officer at Isaac Health, who was not involved in the research. “It’s a matter of helping to support people — asking if they need anything, being available to listen — and that’s something we’re all empowered to do.”

Loneliness differs from being alone

Loneliness is a perception of social isolation and differs from being alone. People can have active social lives and still feel lonely, or live a solitary life and not experience loneliness. Some experts believe that loneliness is the social equivalent of physical pain, hunger and thirst — an unpleasant emotional response that evolved to motivate humans to seek out social connections.

A study from this year suggests that there may be a vicious cycle between loneliness and cognitive decline, even on a day-to-day basis. Data from 313 older adults in the Einstein Aging Study showed that loneliness one day may decrease cognitive performance the following day. Also, when cognitive performance declined, loneliness increased a short time later.

One hypothesis is that feeling lonely leads to reduced social participation, meaning less opportunity for cognitive stimulation and greater vulnerability to cognitive decline. Another possibility is that loneliness is a symptom of dementia that appears decades before an actual diagnosis.

“Dementia develops very gradually over a long period of time, and it affects not just cognition, but all kinds of behaviors,” Wilson said. “So whenever we see a behavior that is predictive of developing dementia, one of the first things we have to wonder is whether it’s really an early sign of dementia.”

Strategies to reduce loneliness

Experts agree that more research is needed to tease out the exact relationship between loneliness and dementia. But if perceived social isolation is somehow contributing to cognitive decline, the good news is that several types of interventions have been shown to reduce loneliness. Interventions that enhance social skills, provide social support, increase opportunities for social interaction, and reframe perceptions of loneliness have had various levels of success in clinical studies.

Approaches to reduce loneliness should be tailored to the individual, but some general suggestions from Salinas include:

• Preserve what you have. Before trying to make new friends, Salinas recommends nurturing the social connections you already have, such as reaching out to family or friends you may have lost touch with. Forming new connections requires more vulnerability and effort than reigniting old ones.
• Find like-minded people. Search for opportunities where you can interact with others through a shared interest such as a book club, sports league or class. Meeting the same people regularly through a scheduled activity increases the chances that a lasting connection will form.
• Maintain good connection hygiene. Be proactive about reaching out to others, instead of waiting for others to reach out to you. Regularly maintain social connections with the people in your lives by asking about their lives and lending a sympathetic ear.
• Cognitive behavioral therapy. Sometimes, loneliness is more related to psychological factors, such as how a person perceives the world around them. Cognitive behavioral therapy is a form of psychotherapy that helps people modify negative thoughts, emotions and behaviors.