title: Hepatic dysfunction is associated with vitamin D deficiency and poor glycemic control in diabetes mellitus.
abstract: OBJECTIVE
  The effect of the rising prevalence of nonalcoholic fatty liver disease on the 25-hydroxylation of pre-vitamin D in the liver, and consequent glycemic control in children with diabetes mellitus is not known. Our aim was to determine whether mild hepatic dysfunction was associated with impaired 25-hydroxylation of pre-vitamin D, and if this vitamin D deficiency was associated with impaired glycemic control in children and adolescents with type 1 diabetes (T1DM) and type 2 diabetes (T2DM).
  
  
  METHODS
  We analyzed simultaneously measured HbA1c, ALT, AST, and 25OHD levels and clinical parameters in 121 children and adolescents with T1DM (n=81) and T2DM (n=40). The subjects, ages 11-21 years, all had diabetes of >6 months duration. Multivariate linear regression was used to analyze the associations, while comparisons between subgroups were made using two-tailed Student's t-test.
  
  
  RESULTS
  Vitamin D deficiency (25OHD <15 ng/mL (37.5 nmol/L) was more prevalent in T2DM patients (47.5%) compared to T1DM patients (18.5%). Subjects with T2DM had significantly elevated transaminases (AST 39.3 +/- 2.0 vs. 22.4 +/- 1.4, p<0.001; ALT 30.6 +/- 1.8 vs. 18.7 +/- 1.3, p<0.001) compared to TIDM patients, and demonstrated a significant inverse relationship between their HbA1c and 25OHD levels (beta=-0.42, p=0.02), compared to T1DM subjects (beta=-0.06, p=0.62).
  
  
  CONCLUSIONS
  The association of elevated ALT with vitamin D deficiency suggests that hepatic dysfunction could impair vitamin D metabolism and negatively impact glycemic control in youth with T2DM.
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA 01655, USA. Benjamin.Nwosu@umassmemorial.org
authors.forename: Benjamin U
authors.initials: BU
authors.lastname: Nwosu
authors.forename: Zheni G
authors.initials: ZG
authors.lastname: Stavre
authors.forename: Louise
authors.initials: L
authors.lastname: Maranda
authors.forename: Karen
authors.initials: K
authors.lastname: Cullen
authors.forename: Mary M
authors.initials: MM
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001786:Blood Glucose / Q000032:analysis*; D002648:Child; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D016014:Linear Models; D008107:Liver Diseases / Q000209:etiology*; D008297:Male; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism; D014808:Vitamin D Deficiency / Q000150:complications*; D055815:Young Adult
chemical_list: D000410:Alanine Transaminase; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D014807:Vitamin D; C517652:hemoglobin A1c protein, human; C104450:25-hydroxyvitamin D