Overview: Loneliness and a lack of social support contribute to a higher risk of developing Alzheimer’s disease or other forms of dementia. The findings add to the growing body of evidence linking social isolation to Alzheimer’s disease.
Source: PLOS
Social lifestyle determinants, including social isolation, are associated with risk factors for neurodegeneration, according to a new study published this week in the open access journal PLOS ONE by Kimia Shafighi of McGill University, Canada, and colleagues.
Alzheimer’s disease and related dementias (ADRD) is a growing public health crisis, with an annual global cost of more than $1 trillion. There is increasing evidence that social isolation is associated with an increased risk of ADRD, but the links between social lifestyle and other known risk factors for ADHD are less well understood.
In the new work, the researchers examined data from 502,506 UK Biobank participants and 30,097 people who took part in the Canadian Longitudinal Study of Aging. Both studies had questionnaires that included questions about loneliness, frequency of social interaction, and social support.
The study found a host of associations between potentially modifiable risk factors for ADHD and both loneliness and lack of social support. Individuals who smoked more, drank alcohol to excess, experienced sleep disturbances, and participated infrequently in light to strenuous physical activity — all known risk factors for ADRD — were more likely to be lonely and lacking social support.
For example, in the CLSA, greater regular participation in physical activity with other people was associated with a 20.1% decrease in the likelihood of feeling lonely and a 26.9% decrease in having poor social support.

Physical and mental health factors previously associated with ADHD, such as cardiovascular disease, visual or hearing impairment, diabetes, and neurotic and depressive behaviors, have also been associated with both subjective and objective social isolation. For example, in the UKBB, hearing impairment with background noise corresponded to a 29.0% increase in the likelihood of feeling lonely and a 9.86% increase in the likelihood of missing social support.
The likelihood of feeling lonely and lacking social support was also 3.7 and 1.4 times greater, respectively, as a function of a participant’s score for neuroticism.
The authors conclude that social isolation, which is more easily modifiable than genetic or underlying health risk factors, may be a promising target for preventive clinical action and policy interventions.
The authors add, “Given the uncertain impact of social distancing measures imposed by COVID-19, our findings underscore the importance of examining the multiscale effect of social isolation to inform public health interventions for ADRD.”
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Source: PLOS
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Original research: Open access.
“Social isolation is linked to classic risk factors of Alzheimer’s-related dementias” by Kimia Shafighi et al. PLOS ONE
Abstract
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Social isolation has been linked to classic risk factors of Alzheimer’s-related dementias
Alzheimer’s disease and related dementias are a major public health burden that will increase in the coming years due to longevity. Recently, clinical evidence pointed to the experience of social isolation in precipitating the onset of dementia.
In 502,506 UK Biobank participants and 30,097 participants in the Canadian Longitudinal Study of Aging, we reviewed traditional risk factors for developing dementia in the context of loneliness and lack of social support.
In these measures of subjective and objective social deprivation, we identified strong associations between individuals’ social capital and several indicators of Alzheimer’s disease and related dementia risk, which replicated in both population cohorts.
The quality and quantity of daily social encounters had deep associations with key etiopathological factors, representing 1) personal habits and lifestyle factors, 2) physical health, 3) mental health, and 4) societal and external factors.
Our population-scale assessment suggests that social lifestyle determinants are associated with most neurodegeneration risk factors, highlighting them as promising targets for preventive clinical action.