Effects of melatonin supplementation on disease activity, oxidative stress, inflammatory, and metabolic parameters in patients with rheumatoid arthritis: a randomized double-blind placebo-controlled trial

Abstract

Considering the pathologic significance of inflammation and oxidative stress in rheumatoid arthritis (RA) as well as the antioxidant, anti-inflammatory and hypolipidemic effects of melatonin, the current research is designed to investigate the effect of melatonin supplementation on disease activity, oxidative stress, inflammatory, and metabolic parameters in RA patients. In this randomized double-blind, placebo-controlled trial, 64 RA cases were selected and randomly assigned into 2 groups to take 6 mg/day melatonin or placebo for 12 weeks. Before and after trial, serum malondialdehyde (MDA), total antioxidant capacity (TAC), erythrocyte sedimentation rate (ESR), lipid profile, fasting blood sugar (FBS), and insulin levels were measured and disease activity was determined by disease activity score-28 (DAS-28). Compared to the baseline, melatonin significantly decreased DAS-28, ESR, MDA, and LDL-C by 50.5%, 59%, 97%, and 13%, respectively (P<0.001) and significantly increased TAC by 89% (P=0.013) and HDL-C by 22% (P<0.001). After treatment, considerable differences were only seen between the two groups in serum MDA (P<0.001) and LDL-C (P=0.007) concentrations, adjusted for baseline measures. Moreover, there were no significant changes in DAS-28, ESR, TAC, triglyceride, total cholesterol, HDL-C, FBS, and insulin levels compared to placebo group (P>0.05). Although melatonin supplementation had no beneficial effects on DAS-28, it could lower serum MDA and LDL-C levels. It seems that melatonin supplementation should not be used as a replace for routine drugs prescribed in RA treatment. Further investigations should be conducted to fully understand the effects of melatonin in RA. Key Points • Compared to baseline, melatonin significantly decreased DAS-28, ESR, MDA, and LDL-C and significantly increased TAC and HDL-C. • After treatment, considerable differences were only seen between melatonin and placebo groups in serum MDA and LDL-C concentrations. • After treatment, there were no significant changes in DAS-28, ESR, TAC, triglyceride, total cholesterol, HDL-C, FBS, and insulin levels compared to the placebo group.