The association between dietary intake of branched-chain amino acids and odds and severity of rheumatoid arthritis

Abstract

Abstract This study examined the relationship between dietary branched‑chain amino acids (BCAAs) and the risk of rheumatoid arthritis (RA) and disease severity. This case-control study was conducted on RA patients and age- and sex-matched healthy controls. Dietary intake of BCAAs was assessed using a food frequency questionnaire, and the amounts of valine, leucine, and isoleucine consumed were summed to calculate total BCAA intake. We assessed the disease severity using the disease activity score 28 (DAS-28), ESR, VAS, morning stiffness, and tender and swollen joints. 95 RA patients and 190 healthy participants participated in the study. After multivariate adjustment, the odds of RA were 2.57 times higher for participants in the highest tertile of BCAAs intake than for those in the lowest tertile (95% confidence interval (CI): 1.14–5.75; P for trend = 0.02); in addition, the highest compared to the lowest tertile of valine was associated with increased risk of RA (OR: 2.31; 95% CI: 1.06–5.02; P for trend = 0.04). However, dietary BCAA intake was not significantly associated with disease severity in either crude or multivariate models. Higher dietary intakes of BCAAs, particularly valine, may contribute to the development of RA.