Background: Low serum vitamin D has been associated with metabolic syndrome and Non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the impact of vitamin D supplementation in treatment of patients with NAFLD. Methods: In a double blind, randomized, placebo controlled trial patients with NAFLD were randomized to receive one weekly pearl of placebo, 50,000 U vitamin D3 (cholecalciferol) pearl per week and 0.25 mg calcitriol (1,25 dihydroxycholecalciferol) pearl per day for 3 months. Results: 106 NAFLD patients were randomized to receive calcitriol, vitamin D3 and placebo pearls for 12 weeks and data for 91 patients were analyzed. After 12 weeks of treatment, serum alkaline phosphatase levels was significantly decreased from baseline levels in vitamin D and calcitriol treated groups (P < 0.05). Serum and gamma glutamyl transferase (GGT) level was also significantly decreased compared to the baseline levels after 12 weeks of treatment with vitamin D. There was no statistically significant difference between placebo, calcitriol, vitamin D groups in terms of serum aminotransferase, alkaline phosphatase, serum GGT and lipid profile (P > 0.05). Conclusion: While significant reduction of serum alkaline phosphatase and GGT were seen with vitamin D and calcitriol supplementation from baseline levels, no beneficial effects was seen when comparing vitamin D, calcitriol and placebo groups at the end of trial. © ۲۰۱۸ Diabetes India. Published by Elsevier Ltd. All rights reserved.

Introduction

Non-alcoholic fatty liver disease (NAFLD) is a spectrum ranging from simple steatosis to steatohepatitis that may lead to liver cirrhosis [1]. It is a rapidly growing disease in many areas of the world with the highest prevalence in the Middle Eastern countries [2,3]. NAFLD is now the most common cause of liver enzyme abnormalities worldwide. It is usually considered as the hepatic manifestation of metabolic syndrome, however, there are patients with NAFLD without components of metabolic syndrome [4]. The precise pathophysiology of NAFLD and its progression to cirrhosis and hepatocellular carcinoma (HCC) is not still clear and several complex underlying mechanisms may involve. On the other hand, NAFLD is not a liver limited disease and extrahepatic diseases have been associated with NAFLD. Cardiovascular diseases are more prevalent in NAFLD patients and are the main cause of mortality among these patients [5,6]. NAFLD is more prevalent in patients with diabetes mellitus and diabetic patients are more susceptible to cirrhosis secondary to NAFLD [7]. Thyroid hormone abnormalities have also been reported in patients with NAFLD in several previous studies [8,9]. Recently, association between NAFLD with bone and vitamin D metabolism have been reported [10]. Vitamin D is a fat-soluble vitamin which is primarily involved in bone and mineral metabolism [11]. In recent decades, other functions have been proposed and discovered for vitamin D in human body. Several previous studies have shown that low serum vitamin D have been associated with metabolic syndrome and diabetes [12–۱۴]. Vitamin D supplementation has been shown to improve insulin resistance and glycemic control in patients with overt diabetes and those with impaired glucose tolerance [15,16]. Considering cumulative evidences about association of vitamin D and NAFLD, this study aimed to investigate the role of vitamin D therapy in amelioration of hepatic steatosis in patients with NAFLD.