Zahra Bagheri-Hosseinabadi - Molecular Medicine Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Fatemeh Moadab - Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Zahra Kamiab - Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Amir Rahnama - Non-Communicable Diseases Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Mitra Abbasifard - Non-Communicable Diseases Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. Department of Internal Medicine, Ali-Ibn AbiTalib hospital, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.

Vitamin D level varies according to the geographic location. This study was conducted to evaluate Vitamin D level in the serumsamples of Systemic lupus erythematosus (SLE) patients from the Iranian population and determine its association with SLE diseaseactivity index (SLEDAI), sun exposure, smoking, photosensitivity, sun protector cream use, and drug regimen. In this crosssectional study, 200 patients were included. The patient’s data were obtained using a questionnaire. The enzyme-linkedimmunosorbent assay (ELISA) technique was used to determine Vitamin D level in the serum samples of the patients. The studypopulation was comprised of 27 (13.5%) males and 173 (86.5%) females, with a mean age of 38.46 ± 13.24 years. The serumlevel of Vitamin D was 13.62 ± 3.22 ng/ml in the patients. Vitamin D deficiency was observed in 104 (52%) patients. There wasa statistically positive correlation between vitamin D level and duration of sun exposure (CC = 0.57, P = 0.004). A statisticallysignificant negative correlation was seen between vitamin D level and SLEDAI (CC = -0.41, P = 0.013).Vitamin D level was significantly (P = 0.030) lower in the SLE patients with photosensitivity. SLE patients using sunprotector cream had significantly (P = 0.002) lower level of Vitamin D. Patients receiving glucocorticoid drugs hadsignificantly (P = 0.001) lower levels of Vitamin D in comparison to the patients not receiving glucocorticoids. Vitamin D isinvolved in the disease activity of SLE patients. It is important to include vitamin D supplementation in the drug regimen of SLEpatients, especially when it includes glucocorticoids.

Vitamin D, Systemic lupus erythematosus, Photosensitivity, disease activity, glucocorticoids