What percentage of people feel lonely?

In a 2021 Cigna survey, 58% of US adults said they felt lonely; the US Surgeon General called it an epidemic in 2023. In the UK, about 7% of adults say they feel lonely often or always. The often-quoted 'as deadly as 15 cigarettes a day' is a popularised reading of a 2010 meta-analysis, which found that weak social ties raise mortality risk by about 50%, comparable to well-known risk factors such as smoking and obesity.

Source: Cigna (2021); US Surgeon General Advisory (2023); ONS Community Life Survey (2023); Holt-Lunstad et al. (2010), PLOS Medicine