The goal of this prospective, randomized, parallel-group design, double-blind, and 6-month follow-up is to evaluate the impact of 4000 IU/day vitamin D on 25-hydroxyvitamin D \[25(OH)D\] levels and inflammatory mediators in people with Rheumatoid Arthritis (RA).
The main questions it aims to answer are
* The level of 25(OH)D and inflammatory mediators of levels of RA differs at baseline and after 6 months of Vitamin D 4000 UI
* The disease activity of AR measured by visual analogue scale (VAS) and Disease Activity Score-28 (DAS-28 score) will change in baseline and after 6 months of Vitamin D 4000 UI Researchers will compare the group of participants with Vitamin D supplementation and group of participants without D Vitamin supplementation
Participants in active group will:
* Take Vitamin D every day for 6 months
* Visit the clinic in the first months and after 6 months for medical visits and tests.