Background25 (OH) D is a steroid prohormone that participates in calcium homeostasis and bone health.1 Nonclassical functions of this vitamin have been described in a variety of cells of the innate and adaptive immune system. Currently, the immunomodulatory role of 25 (OH) D in Systemic Lupus Erythematosus (SLE) continues in debate. In addition, a correlation between non-optimal levels of 25 (OH) D and disease activity has been observed.2 In the SLE, there is a high prevalence of non-optimal levels of vitamin D. A prevalence of 25 (OH) D insufficiency of 15% to 75% is reported.3 ObjectivesTo determine the relationship between vitamin D levels and disease activity in SLE.MethodsIt is a prospective, cross-sectional study, in all patients who attended the rheumatology clinic of the Hospital Docente Padre Billini in the period August – October 2017, where the levels of vitamin D and activity of the disease were measured with SELENA-SLEDAI (≤3 without activity, 3–12 moderate activity,≥12 high activity). Vitamin D deficiency is defined as serum levels of 25 (OH) D<10 ng/ml, insufficiency levels serum levels of 25 (OH) D of <30 ng/ml.3 Inclusion criteria: all patients with at least 18 years of age who met the SLE SLICC 2012 classification criteria were included with determination of vitamin D and calcium.Results45 patients who met criteria SLE SLICC 2012 were included. 97.7% (44) were women. The most frequent age range was 31–45 years. 24.4% (11) had decreased calcium values. The vitamin D values were insufficient in 77.7% (35) of the patients and deficient in 4.4% (2) According to SELENA-SLEDAI, 77.7% (35) had no activity of the disease, 20% (9) had moderate activity and 2.2% (1) had high activity. Of the patients who reported disease activity, only 13.3%6 had insufficient vitamin D. There is no significant difference between patients who have vitamin D values greater than or less than 20 ng/ml. In both groups, the majority had SELENA-SLEDAI in low activity.ConclusionsThe vitamin D levels were not associated with an increase in disease activity in our study patients. Although our country is an island, the use of sunscreen and avoid sunbathing is something common, it causes to find low levels of vitamin D, not only in patients with SLE, where avoiding sunbathing is a recommendation, but also in other pathologies that come to our service. We believe that vitamin D levels should be measured in the general population, to have a reference range and study their influence on health.References[1] Christakos S, Dhawan P, Verstuyf A, Verlinden L, Carmeliet G. Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects. Physiol Rev. 2016; 96:365–408[2] Mandal M, Tripathy R, Panda AK, et al. Vitamin D levels in Indian systemic lupus erythematosus patients: association with disease activity index and interferon alpha. Arthritis Res Ther. 2014;16: R49.[3] Hamza RT, Awwad KS, Ali MK, Hamed AI. Reduced serum concentrations of 25-hydroxy vitamin D in Egyptian patients with systemic lupus erythematosus: relation to dise...