Center forSocial Connection
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Research Center · Est. 2021

Connection is a health outcome.
We publish the evidence.

Independent reviews of the research on social connection, isolation and loneliness. Quantitative. Sceptical. Cited across the field.

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1 in 6

people worldwide affected by loneliness

World Health Organization, Commission on Social Connection, 2025

~30%

higher risk of heart attack or stroke

Journal of the American Heart Association, 2022

871,000

deaths a year linked to loneliness

World Health Organization, Commission on Social Connection, 2025

1.29

mortality odds ratio for social isolation

Perspectives on Psychological Science, 2015

The same word, eight different numbers

Share of adults reported lonely, by survey. These figures are quoted interchangeably. They use different instruments, different thresholds and different populations, so the spread is a fact about the questions, not about a change in how lonely people are.

Cigna2020
61%

“Sometimes or always” lonely · US adults

Cigna / Evernorth2025
57%

Reported loneliness · US adults

HINTS-62025
37%

Moderate-to-severe loneliness · US adults

Harvard MCC2021
36%

“Serious” loneliness · US adults

AARP Foundation2018
33%

UCLA Loneliness Scale, 20-item · US adults 45+

Gallup2023
24%

“Very or fairly” lonely · 142 countries

WHO Commission2025
16%

Affected by loneliness · Worldwide

OECD2025
6%

Lonely most/all of past 4 weeks · OECD average

View as a table
SurveyYearReported lonelyInstrumentPopulation
Cigna202061%“Sometimes or always” lonelyUS adults
Cigna / Evernorth202557%Reported lonelinessUS adults
HINTS-6202537%Moderate-to-severe lonelinessUS adults
Harvard MCC202136%“Serious” lonelinessUS adults
AARP Foundation201833%UCLA Loneliness Scale, 20-itemUS adults 45+
Gallup202324%“Very or fairly” lonely142 countries
WHO Commission202516%Affected by lonelinessWorldwide
OECD20256%Lonely most/all of past 4 weeksOECD average

Research

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Commentary

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From the Library

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Fortune, 2026

America Is Running Out of Places to Hang Out as Movie Theaters, Bars, Diners and Bowling Alleys Drop to All-Time Low

The figures document supply-side contraction of informal gathering venues rather than measured changes in social connection or isolation itself; readers should treat the cost-driver explanation as journalistic interpretation, not a tested causal claim, and pair these counts with survey-based loneliness or contact-frequency data before drawing conclusions about population-level effects.

University of Bristol and Nature Communications, 2026

Loneliness Strongly Linked to Poorer Mental Health and Wellbeing

The findings reinforce a well-established association but the summary provided offers no quantitative effect sizes, sample characteristics, or discussion of directionality, limiting its independent evidentiary value; readers should consult the full paper before citing magnitude of effect or drawing causal conclusions.

Axios, 2026

A Loneliness Epidemic Meets Uneven Social Infrastructure

The piece presents an association between built-environment infrastructure and reported loneliness without establishing a causal mechanism or quantifying the relationship; the noted geographic unevenness suggests local infrastructure data may be more useful than national averages for policy targeting.

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