Loneliness is related to numerous age-related diseases. A recent study investigated the relationship between perceived loneliness and dementia risk. While loneliness has been linked to dementia in prior studies, this was the first study to examine loneliness and the risk of two common subtypes of dementia, Alzheimer’s disease and vascular dementia.
The participants were part of the Betula Prospective Cohort Study, a Swedish longitudinal study that began in 1988. There were six samples in the study overall. They were studied in six waves that were each about five years apart. The current study included 1,905 participants who were at least 60 at baseline and who participated in samples one through five. Loneliness was measured by a single item: “Do you often feel lonely?” Dementia was evaluated at each wave by a senior research geriatric psychiatrist. Multiple sources of information from diagnostic assessments and medical records were considered to make the final diagnosis. All-cause dementia included both Alzheimer’s disease and vascular dementia, as well as six other subtypes. As depression may increase the risk of loneliness, the researchers controlled for depression, which was measured by 20-item self-report scale.
The study found that individuals who were often lonely were more likely to develop all-cause dementia and Alzheimer’s disease even after accounting for factors such as depression. Further, even after the researchers excluded participants who developed dementia within the first five years—persons who could have experienced loneliness as an early sign of dementia—the relationship remained. However, loneliness did not increase the risk of vascular dementia. The relationship between loneliness and Alzheimer’s disease was consistent with a prior study demonstrating that increased loneliness was related to higher cortical amyloid burden, one of the primary components of plaque found in Alzheimer’s disease. While more research is needed, this study takes an important step forward in understanding the relationship between loneliness and types of dementia.
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Sundström A, Adolfsson AN, Nordin M, Adolfsson R. Loneliness increases the risk of all-cause dementia and Alzheimer’s disease. The Journals of Gerontology: Series B. 2020:75(5): 919-26.