Associations between vitamin D deficiency and nonalcoholic fatty liver disease

Abstract

Objective To explore the association between vitamin D deficiency and nonalcoholic fatty liver disease （NAFLD）.Methods From April to June 2013,104 outpatients met NAFLD diagnostic criteria were enrolled.At the same period,98 age and gender matched healthy individuals were enrolled as control.The clinical data were collected through questionnaire,physical examination and lab tests.The severity of hepatic steatosis was dertermined with upper abdominal ultrasound examination.The serum concentration of 25 （OH ）D was detected by radio-immunology.The association between vitamin D deficiency and NAFLD was analyzed with two independent sampling t analysis,chi-square test,analysis of variance （ANOVA）and Logistic regression analysis.Results The clinical indexes including body mass index （BMI ）, abdominal circumference, blood pressure, aspartate aminotransferase, alanine aminotransferase,glutamyl ranspeptidase,lactate dehydrogenase,uric acid,triglyceride,overall cholesterol, lower density lipoprotein cholesterol and fasting blood glucose of NAFLD group were higher than those of the healthy control group,and the differences were statistically significant （all P 〈 0.05）.But the level of higher density lipoprotein cholesterol of NAFLD group was lower than that of the healthy control group, and the difference was statistically significant （t=-2.941 ,P =0.004）.However there was no significant difference in serum 25 （OH）D concentration,the level of calcium and phosphorus （all P >0.05）.The results of stratification analysis in age and BMI indicated that the rate of 25 （OH ）D deficiency （〈37.5 nmol/L）in NAFLD patients aged less than 30 was higher than that of healthy control group （χ^2 =6.679, OR = 13.71,P = 0.025 ）;the rate of 25 （OH）D deficiency in NAFLD patients with BMI≤25 kg/m^2 was higher than that of healthy control group （χ2 = 3.734,OR = 4.97,P 〈 0.01）.Among BMI≤25 kg/m^2 group,after the adjustment of age,gender and metabolic syndrome,the results of multiple group Logistic regression analysis indicated that serum 25（OH）D concentration was negatively correlated to NAFLD （OR= 1 .16,95 % CI ：1 .03 to 1 .30,P = 0.032）.Conclusion Vitamin D deficiency might be a risk factor in pathogenesis of NAFLD patients with age less than 30 year old and BMI ≤25 kg/m^2 . Key words: Vitamin D; Nonalcoholic fatty liver disease; Body mass index; Age