The shelf · Loneliness and solitude
Does The Lonely Century hold up?
The Lonely Century: A Call to Reconnect, by Noreena Hertz (2020)
An economist's account of loneliness as a defining condition of the 21st century, linked to economics, technology and the design of cities.
The short answer
Its health figures are real but come from observational studies, and its dementia figure is the correct result of one study, and a larger review now gives a smaller figure.
The claims, checked
Lonely people face about 29% higher risk of heart disease and 32% higher risk of stroke.
Holds with conditions Matches a 2016 meta-analysis of 23 studies. It combined loneliness with poor social relationships, and the studies show association, not cause.
Evidence: Newcastle University, 2016
Lonely people are 64% more likely to develop dementia.
Holds with conditions The figure is the correct result of one Dutch study of 2,173 people. A 2024 meta-analysis of 21 samples and 608,561 people puts the increase at about 31%.
Lonely people are almost 30% more likely to die prematurely.
Holds with conditions Holt-Lunstad (2015) reports 26% for loneliness, 29% for social isolation and 32% for living alone. These are associations, not proven causes.
Evidence: Holt-Lunstad et al., 2015
Loneliness is as bad for health as smoking 15 cigarettes a day.
Contested The figure comes from a 2010 meta-analysis of weak social relationships, not loneliness, and is a comparison of effect sizes, not a matched dose.
Evidence: Holt-Lunstad et al., 2010