Evaluation of Serum Vitamin D Levels in Patients with Systemic Sclerosis and Healthy Controls: Results of a Pilot Study

BACKGROUND: The anti-inflammatory, immunomodulatory, and anti-proliferative effects of vitamin D in pathogenesis of autoimmune diseases have been highlighted in recent years but implications of vitamin D deficiency in systemic sclerosis (SSc) remain understudied. OBJECTIVES: To evaluate serum vitamin D levels in SSc patients and matched controls. MATERIALS AND METHODS: Serum vitamin D levels were estimated in 38 (M:F 5:33) patients aged 23–70 years of untreated SSc and age and gender matched healthy controls. Clinical and investigative evaluation for skin sclerosis by modified Rodnan skin score (mRSS), presence of digital ulcers, Raynaud's phenomenon, type of auto-antibodies, systemic involvement, and serum vitamin D levels were performed. Serum vitamin D levels were defined as normal (30–100 ng/ml), insufficient (10–30 ng/ml), and deficient (<10 ng/ml). RESULTS: Serum vitamin D levels (median ± IQR) were 19.5 ± 77.8 ng/ml in 38 patients and 100 ± 31.3 ng/ml in controls each. Vitamin D deficiency in 13 (34.2%) and insufficiency in 10 (26.3%) patients were identified. Only 2 (5.3%) controls had vitamin D insufficiency and the difference was statistically significant (P = 0.001). An inverse relationship was observed between mRSS and serum vitamin D levels. CONCLUSIONS: Patients with SSc have significantly lower serum vitamin D levels than healthy controls. Serum vitamin D levels do not correlate well with age, gender, disease duration or its variants, type of auto antibodies, presence of digital ulceration, or systemic involvement but has inverse correlation with skin sclerosis. Better-designed studies will perhaps resolve issues of potential benefits of vitamin D supplementation in modification of disease activity or severity in SSc.