Is being lonely really as bad for you as smoking 15 cigarettes a day?

The corpus does not support the claim that loneliness is equivalent to smoking a specific number of cigarettes. No study measured both exposures in a single population to establish this equivalence. This comparison originated from benchmarking pooled odds ratios from a 2010 meta-analysis of social relationships against a separate meta-analysis on smoking (Holt-Lunstad, 2010). A commentary by Smith, Holt-Lunstad, and Kawachi (2023) in the *American Journal of Epidemiology* explains that this analogy oversimplifies the risk, as relative measures of association cannot determine absolute risk differences. The commentary provides two population attributable fraction comparisons. Regarding general mortality, a meta-analysis of 90 cohort studies found that both social isolation (1.32) and loneliness (1.14) are associated with higher all-cause mortality, with isolation showing a larger association (Wang, 2023). Most mortality meta-analyses exclude deaths from suicide and unnatural causes, which may make these estimates conservative. Some figures on this topic are not yet verified in this corpus and have been left out.

Sources

  1. Holt-Lunstad J et al., 2015 — Loneliness and social isolation as risk factors for mortality: a meta-analytic review Read the source
  2. Holt-Lunstad et al., 2010 — Social Relationships and Mortality Risk: A Meta-analytic Review Read the source
  3. Wang F et al., 2023 — A systematic review and meta-analysis of 90 cohort studies of social isolation, loneliness and mortality Read the source
  4. Holt-Lunstad et al., 2018 — Why Social Relationships Are Important for Physical Health: A Systems Approach to Understanding and Modifying Risk and Protection Read the source
  5. Donovan et al., 2020 — Social Isolation and Loneliness in Older Adults: Review and Commentary of a National Academies Report Read the source
  6. Pantell et al., 2013 — Social Isolation: A Predictor of Mortality Comparable to Traditional Clinical Risk Factors Read the source
  7. Perissinotto et al., 2012 — Loneliness in Older Persons: A Predictor of Functional Decline and Death Read the source
  8. Hilliard et al., 2026 — Investigating relationships between loneliness, social isolation and health Read the source