Comparison of the Impacts of a Dynamic Exercise Program vs. a Mediterranean Diet on Serum Cytokine Concentrations in Women With Rheumatoid Arthritis. A Secondary Analysis of a Randomized Clinical Trial

Abstract

Background: Rheumatoid arthritis (RA) is a disease characterized by a chronic inflammatory state. High pro-inflammatory cytokine levels are associated with disease activity. Exercise and the Mediterranean diet (MD) exert anti-inflammatory effects; however, their impacts on inflammation in RA patients remains unknown. This study aimed to compare the effects of six-months of dynamic exercise program (DEP) vs. MD on pro- and anti-inflammatory cytokine serum concentrations.

Methods: Secondary analysis of a randomized clinical trial in which 90 women with RA were randomly assigned to the DEP (n = 30), MD (n = 30), or control group (n = 30). All patients received pharmacological treatment. Serum concentrations of pro-inflammatory (TNF-α, TNF-β, IL-1β, IL-6 pg/mL) and anti-inflammatory (IL-10, IL-Ra pg/mL) cytokines were measured at baseline and after 6 months using the Luminex technique.

Results: After 6 months of follow-up, we found an improvement of the median percentages changes concentrations of TNF-α (DEP, -12.3; MD, -13.3; control, 73.2; p = 0.01), TNF-β (DEP, -67.4; MD, -54.9; control, 0; p = 0.04), and IL-6 (DEP, -19.9; MD, -37.7; control, 45.5; p = 0.04) in the DEP and MED groups in comparison with control group. IL-1Ra concentrations increased only in the MD group (13.8) compared to levels in the control group (-31.7), p = 0.04. There were no statistically significant differences between DEP and MD groups. Only n = 27 participants in the DEP group, n = 26 in the MD group, and n = 21 in the control group completed the follow-up.

Conclusion: The DEP and the MD have potential effects in the concentrations of pro-inflammatory cytokines compared with those in a control group. Only the MD elevated the concentration of IL-Ra.

Clinical trial registration: [ClinicalTrials.gov], identifier [NCT02900898].

Keywords: clinical trial; cytokines; exercise program; mediterranean diet; rheumatoid arthritis.

FIGURE 1

Flowchart of patients included in the study.

FIGURE 2

Changes of (A) TNF-α, (B) TNF-β, (C) IL-1β, (D) IL-6, (E) IL-10, and (F) IL-1Ra, after 24 weeks of intervention. *Differences between groups were analyzed by Kruskal-Wallis test. ^**Post hoc analysis using Mann- Whitney U test with Bonferroni correction p < 0.05.