MEDITERRANEAN DIET REDUCES 51% LOWER ARTHRITIS RISK IN MEN

Rheumatoid arthritis is an autoimmune disease that can cause painful swelling of the joints, and researchers wonder if lifestyle choices may help prevent its onset. In this study, researchers analyzed the eating habits of 1,721 patients with rheumatoid arthritis and 3,667 healthy controls in Sweden (matched for age, gender, and neighborhood). Those most closely following a Mediterranean diet had a 19% lower risk of rheumatoid arthritis. However, the findings seem to be driven primarily by men, and those with seropositive rheumatoid arthritis (a type of arthritis associated with more painful symptoms). Men who most closely followed a Mediterranean diet had a 51% lower risk of rheumatoid arthritis, while the trend towards lower risk in women was not statistically significant.

BACKGROUND:

The Mediterranean diet has been associated with lower mortality and lower risk of cardiovascular diseases and cancer. Although its components have been analysed in several studies, only one study has specifically investigated the association between Mediterranean diet and risk of rheumatoid arthritis (RA), and reported no association.

METHODS:

Data on 1721 patients with incident RA (cases) and 3667 controls, matched on age, gender and residential area, from the Swedish epidemiological investigation of RA (EIRA), a population-based case-control study, were analysed using conditional logistic regression. The Mediterranean diet score, ranging from 0 to 9, was calculated from a 124-item food frequency questionnaire.

RESULTS:

In the EIRA study (median age of participants 53 years), 24.1% of the patients and 28.2% of the controls had high adherence to the Mediterranean diet (a score between 6 and 9). After adjustments for body mass index, educational level, physical activity, use of dietary supplements, energy intake, and smoking, high adherence reduced the odds of developing RA by 21% (OR 0.79; 95% CI 0.65-0.96) as compared to low adherence (a score between 0 and 2). The OR was even lower among men (OR 0.49; 95% CI 0.33-0.73), but no significant association was found among women (OR 0.94; 95% CI 0.74-1.18). An association between high diet score and low risk of RA was observed in rheumatoid factor (RF)-positive (OR 0.69; 95% CI 0.54-0.88), but not RF-negative RA (OR 0.96; 95% CI 0.68-1.34), and in RA characterised by presence of antibodies to citrullinated peptides (ACPA), but not in ACPA-negative RA.

CONCLUSIONS:

In this large population-based case-control study, the Mediterranean diet score was inversely associated with risk of RA. However, an association was only found among men and only in seropositive RA.