The Association Between Serum Vitamin D Level and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) occur when the triglyceride accumulates in hepatic cells without history of alcohol consumption and strongly associated with insulin resistance, obesity, diabetes mellitus, hypertension, and dyslipidemia. Some studies have suggested the potential role of vitamin D in the pathogenesis of fatty liver disease.

Our aim was to determine the optimum vitamin D levels for NAFLD prevention.

In a cross-sectional study, 2160 referred to a university affiliated nutrition center randomly selected, their demographic, anthropometric, metabolic indices and vitamin D levels were obtained. Fatty liver assessed by fatty liver index (FLI) and confirmed by Fibroscan using controlled attenuation parameter (CAP). Based on the NAFLD score we divide them to two group and cut point for vitamin D calculated by ROC curve.

745 had different degrees of fatty liver (34.5%). Significant difference in stiffness of liver tissue was seen between of vitamin D categories (285.10  30.56, 251.82  42.63 and 201.02  36.08 for severe (< 12.5 nmol/L), moderate (25 > X > 12.5 nmol/L) and mild deficiency (50 > X > 25 nmol/L) respectively). In multivariate analysis age, fasting insulin, and status of vitamin D was the most significant variables in regard to NAFLD pathogenesis. Cut-off point for vitamin D calculated as 18 (nmol/L) for women and 21 (nmol/L) for men.

Results of our study, indicate significant association between vitamin D level and NAFLD score. So, the public’s recommendation to maintain a proper level of vitamin D may be preventative against non-alcoholic fatty liver disease.