Loneliness is a prevalent experience among older adults with significant implications for cognitive health. A recent study spanning 15 European countries found that loneliness was associated with lower cognitive performance across all assessed cognitive domains. This research was published in Psychology and Aging.
Loneliness refers to the gap between desired and actual relationships and presents a public health concern among older adults. Loneliness is associated with numerous negative health outcomes, such as poorer cardiovascular health, increased depressiveness, early mortality, and cognitive decline.
It can trigger physiological responses like inflammation and immune dysregulation, which can harm cognitive health. At the same time, cognitive impairments can worsen loneliness by affecting social relationships, indicating a bidirectional relationship between loneliness and cognitive decline.
Researchers Laura Cachón-Alonso and colleagues used data from the Survey of Health, Ageing and Retirement in Europe (SHARE), specifically Waves 5-8, ranging between 2013 to 2020. This survey employs probability-based sampling, ensuring the representativeness of the older population in each participating country. The final sample consisted of 55,662 adults aged 50 and older, drawn from 15 European countries. Participants were divided into two age groups: those aged 50-64 years and those aged 65-97 years.
Loneliness was assessed using the Three-Item Loneliness Scale, which includes questions about feelings of lack of companionship, feeling left out, and feeling isolated, and a direct question asking participants how often they feel lonely, all rated on a 3-point Likert scale from “often” to “hardly ever/never”. Cognitive function was evaluated across four domains including verbal fluency, numeracy, immediate and delayed recall. The study also controlled for various confounds, including age, sex, geographical area, educational level, partnership status, depressive symptoms, and chronic diseases at baseline.
The researchers found significant age differences in the link between loneliness and cognitive function. For participants aged 65 and older, higher levels of loneliness were predictive of lower cognitive performance across all cognitive domains in subsequent waves.
Specifically, increased loneliness was linked to declines in verbal fluency, numeracy, and immediate recall; however, the association with delayed recall was not significant in the fully adjusted model. Further, lower verbal fluency predicted increased loneliness over time, suggesting a bidirectional relationship. These results suggest that loneliness may be a significant psychosocial risk factor for cognitive decline in older adults.
Interestingly, the study found no significant associations between loneliness and cognitive performance among adults aged 50-64, indicating that the impact of loneliness on cognitive health may increase with age. Future research ought to explore interventions that mitigate the effects of loneliness on cognitive function.
The researchers note the limitation presented by potential selective attrition. While they handled missing data in their analyses, these methods cannot fully eliminate the risk of bias.
The study, “Loneliness and Cognitive Function in Older Adults: Longitudinal Analysis in 15 Countries”, was authored by Laura Cachón-Alonso, Christian Hakulinen, Markus Jokela, Kaisla Komulainen, and Marko Elovainio.
