A Cross-National Comparison of Social Isolation and Cognitive Functioning

Zhiyong Lin and James Raymo

Introduction and Background

As the global population ages, maintaining cognitive health has become a critical public health priority. We know that staying social helps the brain. However, most research looks at only one country or a single age group. This study looked at a bigger picture. Researchers wanted to see the effect of socially isolated on changes in cognitive function as people age. They compared four countries: the United States, England, China, and Mexico. This helped them see how isolation affects the aging brain in different cultures and economies.

Data and Methods

The researchers used longitudinal data from nationally representative health and retirement studies in the United States (N= 18,971) and England (N = 10,164), two high-income countries, as well as Mexico (N = 18,950) and China (N = 20,484), two middle-income countries. The study tracked cognitive performance in individuals aged 45 and older from 2010 to 2018 to see how cognitive health and social isolation interact and change over time. Social isolation status was measured through four specific types of social contact:

• Living with a spouse or partner
• Frequency of contact with children
• Frequency of contact with friends
• Social participation (engagement in community groups or activities)

The team used growth curve models to statistically compare the cognitive functioning trajectories by social isolation status from middle- to older-adult age across the four countries.

Results

The study showed that being socially isolated is a risk factor for worse cognitive health compared to non-isolated adults. However, the cognition gap differed across nations, and the type of isolation that matters most varied by culture.

• The Big Picture: In the U.S., China, and Mexico, isolated adults tended to have lower cognitive functioning than people who stayed social. The cognitive gap between social and isolated adults was more notable in China and Mexico than in the U.S., with the gap in Mexico almost double that of the U.S.

• The Partner Gap: Not having a partner was a strong influence for cognitive decline in China and the U.S., becoming more important with age in China.

• The Impact of Friends and Community: In China, Mexico, and the U.S., contact with friends was a critical factor for favorable cognitive trajectories. In the U.S. and Mexico, friendships became increasingly vital as individuals aged. Across almost all countries, staying active in community and social groups was also linked to better cognitive functioning with age.
• England as an Outlier: In England, the general link between overall isolation and cognitive decline was less distinct than in the other three countries, with differences appearing only after age 70. This discrepancy suggests that other protective factors of cognitive decline may be at play for middle-aged adults.

Policy and Practice Implications

Because the study is observational, the results reflect associations rather than showing direct causal relationships between social isolation and cognitive functioning. These results suggest that interventions must be tailored, as a single approach for social programs  may fail to improve cognitive health in different contexts. Policies and practices must be adapted to the local social structures, age, and cultural norms. Some examples of practices include:

1. Alternative Support: Connecting people through community and support groups can cognitively benefit those who are unpartnered or have limited contact with their children.
2. Offer Third Spaces: Investment should prioritize community centers, social clubs, and learning programs that make social participation and friendships accessible and safe for seniors.
3. Social Isolation Measures: Because social isolation is not universally defined, studies should strive to contribute to harmonization to facilitate cross-national comparisons in social isolation.

Reference

Lin, Z. and Raymo, J. (2026) Social isolation and cognitive functioning trajectories from midlife to later life in four high- and middle-income countries, Longitudinal and Life Course Studies, 17(2): 271–292, DOI: 10.1332/17579597Y2025D000000066

Suggested Citation

Lin, Z and Raymo, J. A Cross-National Comparison of Social Isolation and Cognitive Functioning. CAPAS Research Synopsis 1(2). doi:10.1332/17579597Y2025D000000066

Acknowledgements

Support for this research was provided by R13AG071246-01A1 (J.A. Kelley, PI), P30AG066614 awarded to the Center on Aging and Population Sciences at the University of Texas at Austin by the National Institute on Aging, and by the Office of the Vice President for Research at the University of Texas at San Antonio.