Fish consumption has been thought to reduce the risk of rheumatoid arthritis (RA), but the reported data are conflicting. We aimed to assess the association between fish consumption (overall, lean fish, and oily fish) and the risk of RA. The E3N Study is a French prospective cohort study including 98,995 women since 1990. Dietary data were collected via a validated food frequency questionnaire in 1993. Cox proportional hazards models were used to calculate HRs and 95% CIs for incident RA. Models were adjusted for age and for the main potential confounders including cigarette smoking. Among 62,629 women, 480 incident cases of RA were identified. In the overall population, we did not find a linear association between overall fish consumption and RA risk (p for trend 0.65), but a moderate consumption of fish was associated with a decreased risk of RA (HR 0.74; 95% CI 0.59-0.94 for tertile 2 compared with tertile 1), especially among current or former smokers (HR 0.61; 95% CI 0.44-0.85). Although not statistically significant, a trend towards an inverse association was only found with oily fish consumption (HR 0.81; 95% CI 0.65-1.02), but not with lean fish. Our results suggest that moderate fish consumption could reduce the risk or RA and potentially counterbalance the increased risk of RA induced by smoking. This inverse association might be explained by the omega-3 fatty acid content of oily fish.
Keywords: diet; fish consumption; rheumatoid arthritis; risk factor.