Mediterranean diet and risk of rheumatoid arthritis: a population-based case-control study

Kari Johansson,Daniela Di Giuseppe,Lars Alfredsson,Johan Askling

doi:10.1186/s13075-018-1680-2

Kari Johansson, Daniela Di Giuseppe + Show 2 more

Open Access

https://doi.org/10.1186/s13075-018-1680-2

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Abstract

BackgroundThe 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.MethodsData 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.ResultsIn 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.ConclusionsIn 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.

Highlights

The Mediterranean diet has been associated with lower mortality and lower risk of cardiovascular diseases and cancer
In contrast to the growing number of genetic loci associated with rheumatoid arthritis (RA) risk, the number of identified modifiable risk factors is still limited, which in turn limits the potential for primary prevention
Similar between the groups, and when assessed separately by food item category, the servings per day were similar between patients and controls, except for alcohol consumption, which was slightly lower among patients (7.1 g per day) versus controls (8.5 g per day)

Summary

Introduction

The Mediterranean diet has been associated with lower mortality and lower risk of cardiovascular diseases and cancer. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. In contrast to the growing number of genetic loci associated with RA risk, the number of identified modifiable risk factors is still limited, which in turn limits the potential for primary prevention. Smoking has been shown to increase the risk of RA [1], while a moderate alcohol intake has been associated with decreased risk. The Mediterranean diet is foremost a plant-based diet including high consumption of fruit, vegetables, whole grains and legumes, moderate consumption of fish, white meat and alcohol and low consumption of red meat and sugar. The Mediterranean diet has been associated with lower risk of overall mortality, cardiovascular disease and cancer [9,10,11]. Due to its presumed anti-inflammatory properties [12] the Mediterranean

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