论文范文
Relationship between Nonalcoholic Fatty Liver Disease and Vitamin D Nutritional Status in Extreme Obe
时间:2017-07-10 12:33 来源:未知 作者:admin 点击: 次
Abstract:Aim. To evaluate the relationship of nonalcoholic fatty liver disease (NAFLD) with nutritional status of vitamin D in extreme obesity. Methods. Descriptive cross-sectional study in individuals with class III obesity (BMI ≥ 40 kg/m2), aged ≥ 20 years to < 60 years. Data were obtained for weight, height, waist circumference (WC), and serum 25-hydroxyvitamin D (25(OH)D) levels. Vitamin D analysis was performed by high performance liquid chromatography (HPLC) and the cutoff points used for its classification were < 20 ng/mL for deficiency and 20–29.9 ng/ml for insufficiency. NAFLD gradation was conducted through histological evaluation by liver biopsy. Results. The sample is comprised of 50 individuals (86% female). BMI and average weight were 44.1 ± 3.8 kg/m2 and 121.4 ± 21.4 kg, respectively. Sample distribution according to serum 25(OH)D levels showed 42% of deficiency and 48% of insufficiency. The diagnosis of NAFLD was confirmed in 100% of the individuals, of which 70% had steatosis and 30% had steatohepatitis. The highest percentage of 25(OH)D insufficiency was seen in individuals with steatosis () and steatohepatitis (). All individuals with steatohepatitis presented VDD (). Conclusion. The results of this study showed high prevalence of serum 25(OH)D inadequacy in individuals with class III obesity, which worsens as the stage of liver disease progresses.
1. Introduction
Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases worldwide [1]. NAFLD is characterized by an accumulation of fat in the liver in the absence of such secondary causes as alcohol abuse, viral hepatitis, and so forth [2], while presenting such wide-ranging histological features as simple macrovesicular steatosis and nonalcoholic steatohepatitis (NASH) that can evolve into fibrosis, cirrhosis, or hepatocellular carcinoma [3].
Vitamin D deficiency (VDD) can result from problems relating to the absorption of vitamin D, hydroxylation due to liver failure, improper dietary intake, or inadequate exposure to sunlight. It is the most prevalent micronutrient deficiency in the world, with a billion people estimated to be deficient [4]. Individuals with obesity, including those suffering from liver disease, are more susceptible to VDD [5]. A potential explanation for this deficiency is, when there is damage of the liver, synthesis of 25(OH)D may be impaired by the presence of steatosis.
VDD can exacerbate NAFLD at least in part through an inflammatory-mediated pathway, given how vitamin D mediates its intracellular signals via the vitamin D receptor (VDR), which is constitutively expressed in the liver [6]. VDR expression in the cholangiocytes and hepatocytes of NAFLD sufferers correlated inversely with the extent of the disease [7].
There is limited information on the potential role VDD plays in NAFLD diagnosed via liver biopsy, mainly where NASH is concerned [8]. Thus, the aim of this study is to investigate the relationship between serum 25(OH)D levels and NAFLD staging, as diagnosed via liver biopsy, in extreme obesity.
2. Material and Methods
The study is comprised of 50 individuals with class III obesity (Body mass index [BMI] ≥ 40 Kg/m2), of both sexes, aged ≥20 to <60 years, from a clinic specialized in controlling obesity in the municipality of Rio de Janeiro, in the period from January to December 2013. Pregnant women, nursing mothers, patients with malabsorption bowel disorder, acute and chronic infections, and associated endocrinopathies (hypothyroidism and hypocortisolism), subjects with diabetes and on insulin or oral antihyperglycemic agents, individuals who made use of medication or vitamin supplement containing vitamin D, whose alcohol consumption exceeded 20 g/day in women and 40 g/day in men, individuals who used drugs that can increase risk factor for NAFLD (amiodarone, corticosteroids, synthetic estrogen, tamoxifen, and nifedipine), and individuals who had alcoholic liver disease, viral hepatitis, autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, liver metabolic disorders, and drug-induced hepatitis or another liver disease that was not NAFLD were excluded from the study.
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