title: Effect of a randomised controlled vitamin D trial on insulin resistance and glucose metabolism in patients with type 2 diabetes mellitus.
abstract: The aim of our study was to investigate the influence of a 6-month vitamin D supplementation in patients with noninsulin-requiring type 2 diabetes mellitus. We included 86 patients in a placebo-controlled, randomised, double-blind study. During 6 months patients received Vigantol oil once a week corresponding to a daily dose of 1904 IU or placebo oil, followed by 6 months of follow-up. At start and at 3-month intervals 25OHD, PTH, body mass index, HbA1c, insulin, C-peptide, and homeostasis model assessment-index were measured. The primary outcome was a change in fasting blood glucose and insulin levels. After 6 months of therapy, the verum group's 25OHD had increased to a median of 35 ng/ml in comparison to the placebo group (median 20 ng/ml, p<10-6). PTH tended to decrease in the verum group (25.5 pg/ml vs. 35.0 pg/ml, p=0.08). After 6 months of therapy, 31 patients (78%) achieved a 25OHD concentration of >20 ng/ml. Their HbA1c was significantly lower at baseline (p=0.008) and after therapy (p=0.009) than in patients with 25OHD below 20 ng/ml. C-Peptide, insulin, and HOMA-index did not change significantly in the verum group but fasting insulin was positively correlated with 25OHD concentrations after 6 months of therapy in both groups. There were no significant effects of vitamin D with a daily dose of 1904 IU on metabolic parameters in type 2 diabetes. However, the correlative findings of this study suggest a link of the 25OHD status and metabolic function in type 2 diabetes. Whether vitamin D therapy with higher doses can improve glucose metabolism needs to be investigated in follow-up trials.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Strobel
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Reusch
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Penna-Martinez
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Ramos-Lopez
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Klahold
authors.affiliation: Diabetes Outpatient Clinic Offenbach and Frankfurt am Main, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Klepzig
authors.affiliation: Pharmacy of the Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Wehrle
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Kahles
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine I, Goethe-University Hospital, Frankfurt am Main, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Badenhoop
mesh_terms: D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D010919:Placebos; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use*
chemical_list: D010919:Placebos; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D005947:Glucose