Loneliness follows a U-shaped path across adulthood, study finds

A new study published in Psychological Science reveals that loneliness tends to follow a U-shaped curve across adulthood, decreasing from young adulthood to midlife and increasing in older adulthood.

Loneliness, defined as a subjective feeling of lacking meaningful social connections, is a widespread phenomenon that adversely impacts mental and physical health. Some research has suggested a U-shaped trajectory, with higher levels of loneliness in adolescence and older adulthood compared to midlife. However, findings have been inconsistent, partly due to methodological limitations like the reliance on cross-sectional data and varying measurements of loneliness across studies.

Eileen K. Graham and colleagues set out to address these gaps by conducting a coordinated data analysis (CDA) involving over 128,000 participants from more than 20 countries, ranging in age from 13 to 103. This approach allowed the researchers to harmonize data across multiple studies, providing a more comprehensive picture of how loneliness changes over the adult lifespan.

The study utilized data from nine longitudinal studies: the English Longitudinal Study of Aging (ELSA), the German Socio-Economic Panel (GSOEP), the Health and Retirement Study (HRS), the Household, Income, and Labour Dynamics in Australia (HILDA), Longitudinal Internet Studies for the Social Sciences (LISS), the Origins of Variance in the Oldest-Old: Octogenarian Twins (Octo-Twin), the Swedish Adoption/Twin Study of Aging (SATSA), the Survey of Health, Aging, and Retirement in Europe (SHARE), and the Swiss Household Panel (SHP).

Loneliness was assessed using different scales, including the UCLA Loneliness Scale, the Center for Epidemiologic Studies Depression Scale (CES-D), and a Rasch-Type Loneliness Scale. Data harmonization was a key aspect of the study, ensuring that loneliness scores were comparable across different scales and studies. The researchers also examined various baseline factors such as sex, marital status, physical function, and education to assess their impact on loneliness trajectories over time.

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The analysis revealed a U-shaped trajectory of loneliness across adulthood, with loneliness decreasing from young adulthood to midlife and increasing in older adulthood. This pattern was consistent across the nine longitudinal studies, despite variations in study design and population. The findings suggest that loneliness tends to be lower during middle adulthood, potentially due to more stable social roles and networks, but rises again in older age, possibly due to factors like loss of social connections and declining health.

Several baseline factors, including social isolation, being female, lower education, and greater physical limitations, were linked to higher levels of loneliness. However, most baseline factors did not significantly affect how loneliness changed over time, except for baseline age, which showed that younger individuals at the study’s start experienced a decline in loneliness until midlife, followed by an increase in older adulthood.

Most baseline factors did not significantly moderate the trajectory of loneliness across adulthood. This means that while certain factors, such as social isolation, education, and physical function, were associated with baseline levels of loneliness, they did not necessarily influence how loneliness changed over the lifespan. However, there was one notable exception: individuals who were younger at baseline were more likely to experience a decrease in loneliness until around midlife, followed by an increase in older adulthood.

The study underscores the need for targeted interventions to address loneliness, particularly in older adults who are at higher risk of increasing loneliness as they age.

A notable limitation of the study is the variability in loneliness measures across the nine studies. Although efforts were made to harmonize the data, differences in measurement tools and study designs may still have influenced the results.

The research, “Do We Become More Lonely With Age? A Coordinated Data Analysis of Nine Longitudinal Studies”, was authored by Eileen K. Graham, Emorie D. Beck, Kathryn Jackson, Tomiko Yoneda, Chloe McGhee, Lily Pieramici, Olivia E. Atherton, Jing Luo, Emily C. Willroth, Andrew Steptoe, Daniel K. Mroczek, and Anthony D. Ong.