OBJECTIVE: Vitamin D deficiency has been related to diabetes, hypertension, hyperlipidemia and peripheral vascular disease. In this study, we aimed to investigate the role of vitamin D status in non-alcoholic fatty liver disease. METHODS: We included 211 consecutive subjects to examine the presence of non-alcoholic fatty liver disease. Of these subjects, 57 did not have non-alcoholic fatty liver disease and 154 had non-alcoholic fatty liver disease. RESULTS: The non-alcoholic fatty liver disease group had significantly higher fasting blood glucose (p = 0.005), uric acid (p = 0.001), aspartate aminotransferase (p<0.001), alanine aminotransferase (p<0.001), γ-glutamyltransferase (p<0.0001), alkaline phosphatase (p = 0.028), HbA1c (p<0.001), ferritin (p<0.001), insulin (p = 0.016), C-peptide (p = 0.001), HOMA-IR (p = 0.003), total cholesterol (p = 0.001), triglyceride (p = 0.001) and white blood cell (p = 0.04) levels. In contrast, the non-alcoholic fatty liver disease group had significantly lower 25(OH)D levels (12.3±8.9 ng/dl, p<0.001) compared with those of the control group (20±13.6 ng/dl). CONCLUSIONS: In this study, we found lower serum 25(OH)D levels in patients with non-alcoholic fatty liver disease than in subjects without non-alcoholic fatty liver disease. To establish causality between vitamin D and non-alcoholic fatty liver disease, further interventional studies with a long-term follow-up are needed.

OBJECTIVE: Fetuin-A is a protein secreted from the liver that inhibits arterial calcification deposition and can contribute to insulin resistance. Hyperthyroidism is also associated with insulin resistance. It is not known whether hyperthyroidism has an effect on fetuin-A levels. METHODS: We measured fetuin-A levels and homeostasis model of assessment-insulin resistance before hyperthyroidism treatment was initiated and after euthyroidism was achieved. A total of 42 patients diagnosed with hyperthyroidism were enrolled in this study. Fetuin-A, insulin, high-sensitivity C-reactive protein, fasting blood glucose, free T3 (fT3), free T4 (fT4), and thyrotropin were measured before and after euthyroidism was established. RESULTS: Basal fasting blood glucose, high-sensitivity C-reactive protein, insulin, c-peptide, homeostasis model of assessment-insulin resistance, fT3, fT4 and fetuin-A levels were significantly decreased after euthyroidism was achieved (Table 1). Basal fasting blood glucose (r:0.407, p:0.008), high-sensitivity C-reactive protein (r:0.523, p<0.0001), insulin (r:0.479, p:0.001), homeostasis model of assessment-insulin resistance (r:0.541, p<0.0001), fT3 (r:0.492, p:0.001) and fT4 (r:0.473, p:0.002) were positively correlated with basal fetuin-A levels. Basal thyrotropin levels were significantly negatively correlated (r:-0.553, p<0.0001) with basal fetuin-A levels. CONCLUSION: Our findings suggest that hyperthyroidism influences fetuin-A levels.