Nearly one-third of older adults aged 45 and older feel lonely, and one-fourth of adults aged 65 and older are considered to be socially isolated. As these numbers continue to rise in the United States, a recent 10-year study found significant links between loneliness and dementia risk.
The study – published in Neurology this month – found a three-fold increased risk of subsequent dementia among lonely Americans younger than 80 who would otherwise be expected to have a relatively low risk based on their age and other genetic risk factors.
“Given the pandemic and people’s increase in social isolation, they’ve also been endorsing higher levels of loneliness. Loneliness is not only increasing in prevalence but also is tied to a pretty substantial increase risk in death,” Joel Salinas, MD, the lead author and an assistant professor of neurology at NYU Grossman School of Medicine, told Seasons.
How the study was conducted and what researchers found
Salinas and his colleagues used data from the population-based Framingham Study, which has been following different groups of people since 1948. They analyzed 2,308 participants who were dementia-free at baseline, with an average age of 73.
Participants were asked how often they felt lonely, along with different types of symptoms, such as depression, poor appetite or restless sleep, in a given week. Researchers also studied MRI brain scans and other neurophysiological measures to see if people who were feeling lonely had any differences in their brain structure and performance on cognitive tasks.
The researchers found after examining the participants for over a decade and using rigorous clinical methods, 144 of the 2,308 participants reported feeling lonely three or more days in the past week. Among the 144 lonely participants, 31 developed dementia. In addition, 329 of the 2,308 participants were diagnosed with the disease.
Salinas said no significant association existed between loneliness and dementia in participants aged 80 and older, but participants aged 60 to 79 who were lonely were more than twice as likely to develop dementia. Loneliness was also associated with a three-fold increased risk among younger participants who did not carry the apolipoprotein E gene, also known as the APOE ε4 allele (the strongest genetic risk factor for late-onset Alzheimer’s disease).
The authors concluded the tripling in risk could be related to associations between loneliness and worse neurocognitive markers of Alzheimer’s disease (AD) and related dementia vulnerability.
“In people younger than 80 who don’t have these typical genetic risks, that is where that risk went up much higher, meaning that loneliness had a much more significant role in predicting whether somebody would develop subsequent dementia,” Salinas said.
Researchers also found lonely participants without dementia had poorer executive function (judgment, planning, organization, attention and problem-solving), lower cerebral volumes (which may suggest an increase in vulnerability for developing cognitive decline due to something like AD or other related dementias) and a higher level of white matter injury (a sign of injury in the brain) compared to non-lonely participants.
“Loneliness increases our burden of vascular injury or vascular disease, which then leads to injury in the brain—which may increase our risk of developing Alzheimer’s disease and dementia,” Salinas said.
Other health risks associated with loneliness
Feelings of loneliness and social isolation can also be associated with other well-established dementia risk factors, such as diabetes, hypertension, physical inactivity and hearing loss, Sanul Corrielus, MD, a cardiologist in Philadelphia, told Seasons in an email.
The Centers for Disease Control and Prevention also found adults aged 50 and older who are feeling socially isolated or lonely can have poor social relationships; be at an increased risk of heart disease and stroke; develop higher rates of depression, anxiety and suicide; and have an increased risk of death, hospitalizations and emergency department visits.
Overcoming feelings of loneliness
While it’s not easy to overcome feelings of loneliness and social isolation, Salinas said one of the first things people can do is acknowledge and accept they’re feeling lonely. The next thing is to reach out to people in your network, including family members and people you haven’t been able to keep in touch with.
“They’re going to provide some support that you might be needing and help to kind of articulate what support you actually need,” he said.
Salinas also encourages people to find opportunities to make new connections through volunteering, group activities/classes and virtual events. But if those things don’t help, it’s recommended that people talk with their doctor about their feelings and any symptoms.
“If you are connecting with a friend or family member, just listen to them, notice what’s going on in their life and begin to create new memories and stories,” Salinas said. “All of these types of things can begin to address some of these feelings of loneliness through a greater sense of belonging and connection.”
Researchers from the Boston University School of Public Health, Boston University School of Medicine, University of California, Davis, and the Briggs Institute for Alzheimer’s and Neurodegenerative Diseases at the University of Texas Health Sciences Center San Antonio were also involved in the study.