Cigarette smoking increases the risk of rheumatoid arthritis. Results from a nationwide study of disease-discordant twins

Arthritis Rheum. 1996 May;39(5):732-5. doi: 10.1002/art.1780390504.


Objective: To test the hypothesis that cigarette smoking is associated with susceptibility to rheumatoid arthritis (RA) by comparing smoking history between twins with RA and their unaffected co-twins.

Methods: Interview questionnaires on smoking history were administered to 79 identical (monozygotic [MZ]) and 71 same-sex nonidentical (dizygotic, [DZ]) twin pairs who were discordant for RA, recruited from the Arthritis and Rheumatism Council Twin Study. Results were expressed as odds ratios (OR) with 95% confidence intervals (95% CI).

Results: Although most twin pairs were concordant for smoking history, there was a strong association between ever smoking and RA in the MZ pairs (OR 12.0, 95% CI 1.78-513), with a similar trend observed in the DZ pairs (OR 2.5, 95% CI 0.92-7.87).

Conclusion: The discordance in cigarette smoking history for individuals who are at presumed identical genetic risk for RA supports other data suggesting the role of smoking in disease susceptibility.

Publication types

  • Research Support, Non-U.S. Gov't
  • Twin Study

MeSH terms

  • Arthritis, Rheumatoid / etiology*
  • Disease Susceptibility
  • Diseases in Twins / etiology*
  • Female
  • Humans
  • Male
  • Risk Factors
  • Smoking / adverse effects*
  • Twins, Dizygotic
  • Twins, Monozygotic