Stress, Loneliness and Social Connection in Aging

Terms

The World Health Organization (WHO) defines loneliness as the painful feeling of a gap between the social connection you want and the connection you have, and social isolation as an objective lack of sufficient connections. [1] A person can be isolated without feeling lonely, and the reverse. This page describes research only; it is not mental health care.

Social connection and mortality

A 2010 meta-analysis of 148 studies (308,849 people) found people with stronger social relationships had a 50% greater likelihood of survival (odds ratio 1.50), strongest for broad measures of social integration (1.91) and weaker for simply living alone (1.19, interval including no effect). [2] A 2015 meta-analysis found about 29% higher likelihood of death with social isolation, 26% with loneliness and 32% with living alone, after adjusting for confounders, with comparable effects for objective and subjective measures. [3] Both reviews compared the size of the effect to well-established risk factors for death. [2][3] In the 2015 review, social deficits predicted death more in samples with an average age under 65. [3] WHO's 2025 commission estimated loneliness is linked to about 100 deaths every hour worldwide. [1] Label: established as an association; causation and size in any one person are uncertain.

Dementia and brain aging

A 2023 review of longitudinal studies (40 publications from 32 studies) found frequent social contact and strong social engagement associated with lower dementia risk (relative risks 0.86 and 0.81), and loneliness with higher risk (1.42). Social isolation and social support were not significant, and heterogeneity was high, so the authors called inference tentative. [4] Label: mixed.

Stress and aging biology

• Heart disease. A meta-analysis of 6 prospective studies (118,696 people) found high perceived stress associated with moderately higher risk of coronary heart disease (risk ratio 1.27). [5]
• Epigenetic clocks. A 2026 meta-analysis of 22 studies found loneliness, depression and stress each associated with higher "epigenetic age acceleration" from midlife on, consistently on the second-generation PhenoAge and GrimAge clocks (pooled estimates between 0.07 and 0.10). It noted that whether easing these adversities slows aging is untested. [6]
• What that means. An epigenetic clock score is a biomarker, not a health outcome. See epigenetic clocks and DNA methylation. Label: insufficient evidence that reducing stress changes biological aging or lifespan.

Can anything reduce loneliness?

An umbrella review of seven meta-analyses found three intervention types reduced loneliness: meditation or mindfulness, social cognitive training and social support. Certainty was low or very low. [7] NIA says loneliness and social isolation are associated with higher risks for heart disease, depression and cognitive decline, and offers practical tips for staying connected. [8] For stress, see how to relieve stress, social connection and loneliness and meditation for stress, sleep and anxiety. Label: promising but limited.

Who should get help

Persistent low mood, hopelessness or loneliness that affects daily life is a reason to talk with a health professional; see stress vs anxiety, burnout and depression. In the US, call or text 988 (Suicide & Crisis Lifeline) if you are in crisis; call 911 in an emergency.

Reading headlines

"Loneliness is as bad as smoking" compares statistical associations; it does not mean the effects are identical in an individual. The 2015 review found that participants' initial health status influenced the findings, so illness may be tangled up with isolation. [3]

Related guides

• Smoking, alcohol and healthy aging
• Cognitive health and brain aging
• Healthy aging