Assessment of serum vitamin D level and its relationship with disease activity in adult patients with Systemic Lupus Erythematosus (SLE)

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.