Objectives Physical activity has been shown to decrease inflammatory markers; here we investigate the effect on the clinical presentation of rheumatoid arthritis (RA).

Methods We used the cases from the population-based EIRA study (N=617), followed in the Swedish Rheumatology Quality Register, calculating the odds of having above median level of 28-joint disease activity score (DAS28), physician assessment, pain (visual-analogue scale (VAS), VAS-pain) and activity limitation (health assessment questionnaire (HAQ)) at diagnosis, as an effect of physical activity 5 years before diagnosis, investigated both in categories and dichotomised.

Results Dose–response relationships were seen for all measures; the higher the level of physical activity, the lower the likelihood of having outcome measure above median. Further, regular physical activity associated with 42% reduced odds of having DAS28 above median (OR=0.58 (95% CI 0.42 to 0.81)). Effects were similar for VAS-pain (OR=0.62 (95%CI 0.45 to 0.86)) and physician assessment (OR=0.67 (95%CI 0.47 to 0.95)) but not for HAQ. Statistically significant effects were also found both for the combined objective components and the combined subjective components of DAS28.

Conclusions Physically active individuals seem to present with milder RA, which adds to the evidence of beneficial effects of physical activity on inflammatory diseases. The observation should be important for both health professionals and individuals seeking to reduce their risk.