The role of diet in susceptibility to rheumatoid arthritis: A systematic review

Objective. Many studies have examined the role of diet in the management of established rheumatoid arthritis (RA), warranting several recent reviews. However, none have considered the possible link between diet and the onset of RA in detail. Studies investigated a possible effect of individual components of diet and the development of RA, but the lack of a systematic review means there is no unbiased assessment of the evidence. Methods. We systematically reviewed studies with comparison groups that examined dietary intake or biological markers prior to the onset of RA. Four electronic databases were searched to identify relevant reports. Six quality criteria were agreed, against which the studies were assessed. The main outcome measure was a diagnosis of RA according to the ARA 1958 or revised ACR 1987 classification criteria. Results. Fourteen reports were included in the review. There was evidence of a protective effect of higher consumption of olive oil, oil-rich fish, fruit, vegetables and B-cryptoxanthin. Lower serum concentrations of antioxidants were associated with an increased risk of RA in 3 studies. Due to the heterogeneity of study designs and analyses, the results could not be pooled. Conclusion. Evidence exists that diet may play a role in the etiology of RA, but it is inconclusive due to the small number of studies available and variation in study design.