Influence of dietary habits on depression among patients with rheumatoid arthritis: A cross-sectional study using KURAMA cohort database

OBJECTIVE: Although mental disorder is one of the most common comorbidities of rheumatoid arthritis (RA) and is known as a critical influence on RA remission rates, there is little knowledge regarding a possible therapeutic strategy for depression or anxiety in a RA population. Most recently, clinical evidence of dietary improvement for depression has emerged in a general population, but the relationship between dietary habits and mental disorder has not been investigated in RA. The purpose of this study is to elucidate clinical associations between mental disorder (depression/anxiety), dietary habits and disease activity/physical function in patients with RA. METHODS: A cross-sectional study was performed with 267 female outpatients from the KURAMA database. Using the Hospital Anxiety and Depression Scale (HADS), we classified the participants into three groups by depression state, and their characteristics were compared. Using the 20-items on the self-reported food frequency questionnaire, we investigated the relationship between dietary habits and depression or anxiety, adopting a trend test and a multivariate standardized linear regression analysis for the HADS score of depression or that of anxiety as a dependent variable. RESULTS: According to the classified stage of depression, current disease activity (DAS28-CRP: 28-Joint RA Disease Activity Score-C-reactive protein) and the health assessment questionnaire disability Index (HAQ-DI) were significantly increased. Trend analyses revealed that the depression score was inversely associated with the consumption of three food (fish, vegetables and fruit) out of twenty as was the anxiety score with only fish intake. Furthermore, multiple linear regression analysis revealed that the depression score was negatively associated with frequent fish intake (≥ 3 times per week) (Estimate -0.53, p = 0.033), HAQ-DI score within normal range (Estimate -0.88, p ≤ 0.001) and MTX use (Estimate -0.60, p ≤ 0.023). For the anxiety score, multivariate analysis showed similar but not significant associations with variables except for HAQ-DI score. CONCLUSIONS: In a RA population, both depression and anxiety had a significant and negative association with HAQ-DI score, and depression rather than anxiety had negative association with frequent fish intake. Modification of dietary habits such as increased fish consumption may have a beneficial effect on the depression state in RA patients.