Low vitamin D levels and non-alcoholic fatty liver disease, evidence for their independent association in men in East China: a cross-sectional study (Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China))

Abstract

Recent studies have suggested an association between vitamin D and non-alcoholic fatty liver disease (NAFLD); however, some results are subject to debate. This study was carried out to evaluate the correlation between NAFLD and vitamin D in men and women in East China. The data were obtained from a cross-sectional study that focused on the health and metabolic status of adults in sixteen areas of East China. According to ultrasonic assessments, the patients were divided into normal and NAFLD groups. Demographic characteristics and biochemical measurements were obtained. Binary logistic regression analysis was used to explore the association. In total, 5066 subjects were enrolled, and 2193 (43·3 %) were diagnosed with NAFLD; 84·56 % of the subjects showed vitamin D deficiency. Subjects with high vitamin D levels had a lower prevalence of NAFLD, particularly male subjects. Within the highest quartile of vitamin D levels, the prevalence of NAFLD was 40·8 %, whereas the lowest quartile of vitamin D levels showed a prevalence of 62·2 %, which was unchanged in women across the vitamin D levels. Binary logistic analysis showed that decreased vitamin D levels were associated with an increased risk of NAFLD (OR 1·54; 95 % CI 1·26, 1·88). This study suggests that vitamin D levels are significantly associated with NAFLD and that vitamin D acts as an independent factor for NAFLD prevalence, particularly in males in East China. Vitamin D interventional treatment might be a new target for controlling NAFLD; elucidating the mechanism requires further research.Key words: Vitamin D: Non-alcoholic fatty liver disease: BMI: Homoeostasis model assessment: Insulin resistance Non-alcoholic fatty liver disease (NAFLD), alternatively known as metabolic fatty liver disease, is associated with insulin resistance, dyslipidaemia, obesity and the metabolic syndrome (1) . In parallel with the obesity epidemic, NAFLD has become one of the most common causes of chronic liver disease in the world. Up to 30 % of adults are affected by NAFLD in America (2) . A study from China reported that the prevalence of NAFLD was as high as 20 % (3) . Vitamin D deficiency (VDD) can be a result of inadequate or limited exposure to sunlight, improper diet or problems related to absorption of vitamin D. Certain diseases can impair vitamin D conversion into its active form. Some of these conditions include kidney disease, liver disease or some hereditary diseases. VDD usually results in bad mineralisation of bones, leading to bone softening, osteomalacia, rickets and osteoporosis. As VDD is a risk factor for developing these metabolic deficiencies and has been linked to disorders in bone metabolism, more recent studies have suggested that obesity and visceral obesity occur with VDD. The potential association between VDD and NAFLD has been examined in recent studies. Mohamed et al. (4) reported that VDD is an important risk factor for NAFLD, and Kong et al.(5) observed that VDD might up-regulate endogenous fatty acid synthesis in non-alcoholic steatohep...

Active form of vitamin D ameliorates non-alcoholic fatty liver disease by alleviating oxidative stress in a high-fat diet rat model

“…VDD is prevalent among NAFLD patients and is independently associated with NASH [24][25][26]. Nakano et al demonstrated that sunlight therapy increased serum 1,25(OH) 2 D 3 levels and ameliorated NASH progression in a choline-deficient and iron-supplemented l-amino acid-defined (CDAA) diet-induced NASH rat model [27].…”

Relationship between adipose tissue dysfunction, vitamin D deficiency and the pathogenesis of non-alcoholic fatty liver disease

“…The existence of an independent association between hypovitaminosis D and NAFLD has been largely demonstrated in studies conducted using liver imaging[132-136] and biopsy[137,138]. In particular, low vitamin D levels were associated with the histological severity of NAFLD/NASH[137-143] and with the prevalence of NAFLD among individuals with normal liver enzymes[131].…”

Low Levels of Serum β-Carotene and β-Carotene/Retinol Ratio Are Associated with Histological Severity in Nonalcoholic Fatty Liver Disease Patients

“…Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases worldwide, affecting more than 30% of the adult population in many developed countries, including China [1]. NAFLD covers a broad spectrum of fatty liver disease, ranging from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and ultimately hepatocellular carcinoma [2].…”