Asthma and allergies may be associated with increased risk of rheumatoid arthritis (RA), according to a recent study. However, passive smoke exposure and earlier age of starting smoking do not appear to influence risk of RA. This case‐control study identified 1,023 cases of RA (175 incident) within a single‐center biobank population using a rules‐based algorithm that combined self‐report with 2 diagnosis codes. Exposures were self‐reported on biobank questionnaires. Logistic regression models calculated the association of exposures with RA, adjusting for potential confounders. Researchers found:

• After adjusting for allergies, urban environment, and passive smoke exposure, asthma was associated with RA in the full cohort (OR 1.28) but not the incident cohort (OR 1.17).
• History of allergic disease was associated with RA in both the full (OR 1.30) and incident cohorts (OR 1.61), especially food allergy (OR 1.38 and OR 1.83, respectively).
• Passive smoke exposure at home or work was not associated with RA.
• Finally, age of starting smoking was not associated with increased odds of developing RA in either the full (OR 1.03) or incident cohorts (OR 1.00).