%0 Journal Article %T Vitamin D Levels Are Associated with Expression of SLE, but Not Flare Frequency %A Marline L. Squance %A Glenn E. M. Reeves %A Huy A. Tran %J International Journal of Rheumatology %D 2014 %I Hindawi Publishing Corporation %R 10.1155/2014/362834 %X This study explores links between vitamin D deficiency (25(OH)D = 50£¿nmol/L) and serological autoimmunity (ANA > 1£¿:£¿80) and frequency of self-reported flares (SRF) in participants with clinical autoimmunity (SLE). 25(OH)D levels of 121 females were quantified and compared. The cohort consisted of 80£¿ACR defined SLE patients and 41 age and sex matched controls. Association analysis of log2 (25(OH)D) levels and ANA 80 positivity was undertaken via two-sample -tests and regression models. Significant differences were found for 25(OH)D levels (mean: control 74£¿nmol/L (29.5£¿ng/ml); SLE 58£¿nmol/L (23.1£¿ng/ml), ), 25(OH)D deficiency (). Regression models indicate that, for a twofold rise in 25(OH)D level, the odds ratio (OR) for ANA-positivity drops to 36% of the baseline OR. No link was found between SRF-days and 25(OH)D levels. Our results support links between vitamin D deficiency and expression of serological autoimmunity and clinical autoimmunity (SLE). However, no demonstrable association between 25(OH)D and SRF was confirmed, suggesting independent influences of other flare-inducing factors. Results indicate that SLE patients have high risk of 25(OH)D deficiency and therefore supplementation with regular monitoring should be considered as part of patient management. 1. Background Systemic lupus erythematosus (SLE) is a systemic autoimmune illness with a complex and multifactorial pathogenesis [1]. Patients can exhibit a wide range of symptoms including increased photosensitivity to ultraviolet radiation (UV) exposure, combined with immunological markers of antinuclear antibody positivity. It is thought that UV exposure may be a catalyst to symptom exacerbation or flare events [2¨C4] and therefore SLE patients are often advised to adopt sun-protective measures of using both physical and chemical barriers on a routine basis. Although the use of UV protective measures is important as a management strategy, it is undertaken with reservation, as adopting such measures may result in vitamin D deficiency and insufficiency reducing individual patient capacity to maintain vitamin D synthesis within the skin. Mechanisms of UV-related influences in SLE range from induction of anti-double stranded DNA (anti-dsDNA) autoantibody production resulting in skin lesion exacerbation [3] through the possibility that vitamin D effects may be inhibited by SLE patient serum autoantibodies (anti-vitamin D) [5]. It is clear that vitamin D is an important hormone with immunomodulating properties [6¨C8] and has a vital role in a large number of biologic and biochemical pathways [3, %U http://www.hindawi.com/journals/ijr/2014/362834/