Comparison of Vitamin D Serum Values between Rheumatoid Arthritis and Lupus Populations: An Observational Study

Sahebari Maryam1, Elham Atabati1, 2, *, Ravanshad Yalda3
1 Rheumatic Diseases Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
2 Cellular and Molecular Research Center, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran
3 Clinical Research Development Unit, Ghaem Hospital, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

© 2018 Maryam et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Rheumatic Diseases Research Center, Mashhad University of Medical Sciences, Elham Atabati, Mashhad, Iran; Tel:4989173000474 / +985138012753; Email:



In recent years, the role of Vitamin D (VitD), as an immunomedulator in autoimmune diseases, has been evaluated in basic science and practice. There is a considerable volume of data on the effect of VitD position in lupus and rheumatoid arthritis exacerbation.


This study aims to compare VitD serum values in lupus (SLE) and Rheumatoid Arthritis (RA) in the geographical region of northeastern Iran.


Lupus and RA Patients were selected with various disease activity levels. All the patients received an equal amount of VitD supplementation and were selected by the same inclusion and exclusion criteria. VitD serum values were measured by a commercial ELISA kit. Data were analyzed in SPSS-15.


A total of 148 SLE and 156 RA patients were studied. VitD serum levels were 66.54±41.2 nmol/l in the SLE group and 83.74±46.45 nmol/l in the RA group. Statistical analysis showed that VitD serum levels were lower in lupus patients than RA ones (p=0.006).


Since VitD deficiency is very common in Iran, physiologic doses of VitD supplementation in patients lead to higher serum levels of VitD. Lower VitD values in lupus patients compared with RA ones may stem from intestinal malabsorption, higher doses of corticosteroid therapy, renal involvement and proteinuria, different polymorphisms of VitD receptors, and more sun protection strategies in lupus patients.

Keywords: Vitamin D, 25(OH) D, VitD, Rheumatoid Arthritis, Lupus, SLE, RA.