Mediterranean diet and remission in rheumatoid arthritis: findings from the EIRA study

Newly diagnosed patients with rheumatoid arthritis (RA) often ask whether diet can influence disease activity, yet evidence remains limited. We investigated whether prediagnosis adherence to a Mediterranean diet is associated with remission 6 months after diagnosis.

We included incident RA cases from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study, with follow-up through the Swedish Rheumatology Quality Register. Remission at 6 months was defined using 5 alternative criteria (eg, 28-joint Disease Activity Score [DAS28], Boolean or combinations of their components). Prediagnosis diet was measured with a 124‑item food‑frequency questionnaire, and Mediterranean diet adherence was scored from 0 to 9. Modified Poisson regression estimated adjusted risk ratios (RRs) and 95% CIs for remission, comparing the highest vs the lowest Mediterranean diet tertiles. Analyses were stratified by RA autoantibody status (rheumatoid factor and/or anticitrullinated protein antibodies).

Among 1510 incident RA cases (77% autoantibody-positive), higher Mediterranean diet adherence was associated with DAS28 remission in autoantibody-positive RA (59% vs 49%, RR: 1.24; CI: 1.07-1.44), but not in autoantibody-negative RA (49% vs 58%, RR: 0.84; CI: 0.65-1.09). A similar pattern appeared for Boolean remission (autoantibody-positive: 35% vs 28%, RR: 1.24; CI: 0.98-1.57; autoantibody-negative: 31% vs 32%, RR: 1.00; CI: 0.67-1.49). In contrast, Mediterranean diet adherence was not associated with minimal objective inflammatory activity (28-swollen joint count ≤ 1 and C-reactive protein ≤ 1 mg/dL).

Greater adherence to a Mediterranean diet at RA onset is associated with higher chances of remission in autoantibody-positive, but not in autoantibody‑negative RA.