The global aging population is increasing rapidly, with WHO predicting that by 2050, one in five people will be 60 or older, with 80% residing in low- to middle-income countries. This demographic shift presents challenges for individuals, families, and public health systems, particularly in Mexico, where 7.8% of the population is over 65. Loneliness, a subjective feeling of isolation despite social connections, differs from social isolation, which is an objective lack of social contact. While the two are related, their correlation varies. Aging is a risk factor for both, with loneliness affecting 10–50% of older adults and social isolation ranging from 6–43%. In Mexico, loneliness prevalence is between 13.2% and 34.9%, while social isolation affects 34–43%. Both conditions are associated with increased risks of cardiovascular diseases, infections, sleep disturbances, cognitive decline, and depression. However, their impact on mortality remains debated, with some studies indicating an increased risk while others do not find them to be decisive factors. The combined effect of loneliness and social isolation on health is still unclear, especially in collectivist, middle- and low-income societies like Mexico, where cultural and socioeconomic factors influence health outcomes.
Methods
This study is an observational retrospective cohort study that included Mexican adults over 50 years old. Participants with incomplete data on loneliness and social isolation were excluded. The study utilized data from the Mexican Health and Aging Study (MHAS), a longitudinal cohort study initiated in 2001 to examine aging, disease, and disability. The 2015 wave of MHAS data was used to assess loneliness, social isolation, and other socio-demographic, clinical, psychological, and lifestyle factors. Mortality data was obtained from the 2018 follow-up.
Results
The study analyzed data from 11,713 participants, with a mean age of 66.6 years, of whom 58.2% were women. Most had no prior hospitalizations (86.7%), while 9.5% had experienced up to five, and 3.9% had more than five. Over a three-year follow-up, the all-cause mortality rate was 6.0% (n = 707). Loneliness and social isolation were prevalent, with 42.05% of participants experiencing loneliness and 53.34% classified as socially isolated. Higher loneliness levels were linked to financial difficulties, depressive symptoms, lower life satisfaction, and increased falls. Social isolation was also associated with financial struggles and depression, though life satisfaction was similar among isolated and non-isolated individuals. While multimorbidity increased with loneliness, it was not significantly higher among the socially isolated.
The study found a strong relationship between loneliness, social isolation, and mortality. Mortality was highest (10.5%) among individuals facing both severe loneliness and social isolation, while those with no loneliness and strong social integration had the lowest mortality rate (4.1%). In the unadjusted analysis, severe loneliness (OR = 1.73) and social isolation (OR = 1.50) were linked to higher mortality risk. However, after adjusting for socio-demographic, clinical, psychological, and lifestyle factors, only social isolation (OR = 1.30) remained a significant predictor of mortality, while loneliness alone did not significantly impact death rates. Correlation analysis showed a weak but significant link between loneliness and social isolation, indicating that social isolation contributes to feelings of loneliness. Living alone was moderately associated with both conditions. However, the interaction between loneliness and social isolation did not significantly increase mortality risk beyond the individual effect of social isolation.
Conclusion
The study found that social isolation is a significant predictor of all-cause mortality in older Mexican adults, while loneliness alone is not. This challenges the assumption that loneliness is equally harmful across all cultures, particularly in collectivist societies. The findings emphasize the importance of community integration and support systems in promoting better health outcomes. Public health interventions should prioritize reducing social isolation through community involvement, family engagement, and social programs that strengthen social networks. Addressing social isolation can enhance the well-being and longevity of older adults, especially in societies where family and community support are central.
Impact of the research
The research has significant public health implications, particularly for collectivist societies like Mexico. Combating social isolation through community-based programs, such as neighborhood support groups, social clubs, and intergenerational initiatives, could enhance social participation and improve health outcomes. Policies promoting active aging, including volunteer opportunities and social spaces for older adults, may further support mental and physical well-being. Given the cultural emphasis on family bonds, family-centered interventions are also essential. Encouraging family involvement in caregiving and social activities, while providing resources to caregivers, can help mitigate the negative effects of social isolation on older adults.
Keywords: Loneliness, Social isolation, Mortality, Older adults, Mental health.