To investigate the correlation between serum 25-hydroxy vitamin D₃ levels and liver fat content (LFC) in patients with type 2 diabetes mellitus (T2DM).

From 2015 to 2018 a total of 382 patients with T2DM hospitalized in autumn and winter in our hospital were recruited. Based on the presence of fatty liver diagnosed with ordinary B-ultrasound, patients were divided into group with nonalcoholic fatty liver (n=242, 130 male, 112 female) and group without (n=140, 78 male, 62 female). Serum 25-hydroxyvitamin D₃ was detected using electrochemiluminescence. One hundred and forty-one patients (82 male, 59 female) who have received insulin administered subcutaneously for at least half a year and had glycated hemoglobin A_1c level less than 7.5% were selected from 382 patients to be carried out quantitative examination of liver ultrasonic fat. The pictures with legible liver and renal were used to calculate LFC with software NIH image J. The correlation between 25-hydroxyvitamin D₃ and LFC, body mass index (BMI), waist circumference and homeostasis model assessment of insulin resistance (HOMA-IR) were analyzed by simple correlation analysis and partial correlation analysis. The correlation between 25-hydroxylvitamin D₃, HOMA-IR and LFC was analyzed by one-way ANOVA test.

(1) Compared to the group without fatty liver, 25-hydroxyvitamin D₃ level of the group with fatty liver was significantly lower [(51±21) vs (42±17) nmol/L, t=4.60, P<0.05]. (2) The level of serum 25-hydroxyl vitamin D₃ in T2DM patients was negatively correlated with LFC (r=-0.272, P=0.005) after adjusting for age, duration of diabetes, BMI, waist circumference, and blood lipid levels. (3) Among patients with T2DM, significantly negative correlation between 25-hydroxyl vitamin D₃ levels and LFC were found in top quartile of HOMA-IR (most severe insulin resistance) (r=-0.499, P=0.003). After adjustment of BMI and waist circumference, 25-hydroxy vitamin D₃ levels were still negatively correlated with LFC (r=-0.463, P=0.008).

Serum 25-hydroxyvitamin D₃ levels are lower in T2DM patients with fatty liver than that of the group without fatty liver. Serum 25-hydroxy vitamin D₃ levels have a negative correlation with LFC, especially in condition of severe insulin resistance.

Diabetes mellitus, type 2; Calcifediol; Nonalcoholic fatty liver diseases; Liver fat content