Memory loss often accompanies healthy aging, but certain factors can exacerbate this decline. For example, social isolation and loneliness are significant but preventable contributors.
Social isolation refers to a lack of social connections, including the size of one’s social network, the frequency of social activities, and the diversity of these connections. Loneliness is the negative emotional state that arises from a gap between desired and actual social interactions.
Despite their recognized importance, few studies have examined the combined effects of social isolation and loneliness on memory over time. Most existing research looks at these factors separately in older populations (60 years or older) and over shorter periods (around three years).
To address these gaps, Ji Won Kang — a PhD candidate at the University of Waterloo — and colleagues examined the effects of social isolation and loneliness on memory over six years in participants aged 45 to 85 years old. They categorized participants into four groups: socially isolated and lonely (“both” group), only socially isolated, only lonely, and neither.
Published in the Archives of Gerontology and Geriatrics, the research used data from the Canadian Longitudinal Study on Aging, assessing participants at baseline, three, and six years. Social isolation and loneliness were measured using different subjective metrics, while memory was evaluated through immediate and delayed recall tests.
Of over 12,000 participants, 83% were neither socially isolated nor lonely. About 8% were only socially isolated, 8% were only lonely, and 1% were both isolated and lonely.
The “neither” group was generally younger, not clinically depressed, and had fewer chronic health conditions compared to the other groups. More women were in the “only lonely” group, and the “both” group had more health issues and lower incomes.
Memory impairment at baseline and three-year follow-up was twice as high in the “both” group compared to the “neither” group, and three times higher at the six-year follow-up. Loneliness alone had a greater negative effect on memory than social isolation, highlighting the powerful impact of negative subjective feelings (loneliness) on cognitive health compared to objective reality (social isolation).
The study confirmed that being in the “both” group was associated with more severe memory impairments. The researchers suggest, however, that those who are socially isolated and lonely may face structural barriers to social engagement due to lower socioeconomic status. Addressing these barriers could involve providing affordable transportation to remain social with friends and family, and implementing social programs to promote sociability, such as group-based social outings to museums in person or online.
Understanding these dynamics can help design interventions to mitigate memory decline in healthy aging, especially in lower-income middle-aged and older Canadians.
