Loneliness may play a significant role in dementia risk, new research has found, with indications that such risk could be raised three-fold as a result of being isolated.
Researchers looking at links between social isolation in older adults and dementia found a notable link, with dementia risk found to the three times greater among lonely people younger than 80 who would otherwise be considered at low possibility of developing dementia, based on age and genetic risk factors.
The study also found that loneliness was associated with poorer executive function – including decision-making, planning, cognitive flexibility, and control of attention – and changes in the brain that indicate vulnerability to Alzheimer’s disease and related dementias (ADRD).
“This study emphasises the importance of loneliness and issues of social connection in addressing our risk of developing dementia as we age,” says lead investigator Dr Joel Salinas, the Lulu P. and David J. Levidow assistant professor of neurology at NYU Grossman School of Medicine and member of the Department of Neurology’s Center for Cognitive Neurology.
“Acknowledging signs of loneliness in yourself and others, building and maintaining supportive relationships, providing much-needed support for the people in our lives who are feeling lonely—these are important for everyone.
“But they’re especially important as we age, to increase the chances that we’ll delay or perhaps even prevent cognitive decline.”
With more than 55 million people worldwide currently living with dementia, many have experienced loneliness through the isolation of lockdowns during the COVID-19 pandemic.
“This study is a reminder that, if we want to prioritise brain health, we can’t ignore the role of psychosocial factors like loneliness and the social environments we live in day-to-day,” says Dr Salinas.
“Sometimes, the best way to take care of ourselves and the people we love is simply to regularly reach out and check in—to acknowledge and be acknowledged.
“We can share with each other when we’re feeling lonely, appreciate with each other how loneliness is common, and accept that giving and asking for support can be hard. Fortunately, loneliness can be cured. And although we might need to be vulnerable and creative in figuring out new ways to connect, chances are that even the smallest gesture will have been worth it.”
The study was carried out using retrospective data of the population-based Framingham Study (FS), with researchers reviewing 2,308 participants from the United States who were dementia-free at baseline, with an average age of 73.
Neuropsychological measures and MRI brain scans were obtained at examination and participants were asked how often they felt lonely, along with other depressive symptoms, such as restless sleep or poor appetite.
Participants were also assessed for the presence of a genetic risk factor for Alzheimer’s disease called the APOE ε4 allele.
Overall, 144 of the 2,308 participants reported feeling lonely three or more days in the past week.
The study population was assessed over a decade for dementia using rigorous clinical methods, and 329 of the 2,308 participants were subsequently diagnosed with the disease.
Among the 144 lonely participants, 31 developed dementia.
While there was no significant association between loneliness and dementia in participants aged 80 years or older, younger participants aged 60 to 79 who were lonely were more than twice as likely to develop dementia.
Loneliness was associated with three-fold increased risk among younger participants who did not carry the APOE ε4 allele.
Researchers concluded that the tripling in risk was possibly related to associations between loneliness and early cognitive and neuroanatomical markers of ADRD vulnerability, raising potential population health implications for observed trends in loneliness.
Additional findings showed that loneliness was related with poorer executive function, lower total cerebral volume, and greater white-matter injury, which are indicators of vulnerability for cognitive decline.
