The effect of different doses of vitamin D-3 on markers of vascular health in patients with type 2 diabetes: a randomised controlled trial

M. D. Witham (Lead / Corresponding author), F. J. Dove, M. Dryburgh, J. A. Sugden, A. D. Morris, A. D. Struthers

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    Abstract

    Low 25-hydroxyvitamin D levels predict future cardiovascular events and are common in patients with type 2 diabetes. We compared the effect of 100,000 and 200,000 IU doses of vitamin D-3 on endothelial function, blood pressure and markers of glycaemic control in patients with type 2 diabetes.

    This was a randomised, parallel group, placebo-controlled trial. Patients with type 2 diabetes and baseline 25-hydroxyvitamin D levels < 100 nmol/l were enrolled from community and hospital-based diabetes clinics. Participants were assessed in a university department of clinical pharmacology and received a single oral dose of placebo or vitamin D-3 (100,000 IU or 200,000 IU) at baseline, randomly allocated via numbered bottles prepared offsite; participants and investigators were both blinded to treatment allocation. Endothelial function, office blood pressure, B-type natriuretic peptide, insulin resistance and glycosylated haemoglobin were measured at baseline, and at 8 and 16 weeks.

    We randomised 61 participants to the three groups (placebo 22, 100,000 IU vitamin D-3 19, 200,000 IU vitamin D-3 20). There was no significant difference in the primary outcome of endothelial function at 8 weeks (placebo 5.2%, n = 22; 100,000 IU 4.3%, n = 19; 200,000 IU 4.9%, n = 17) or at 16 weeks. Insulin resistance and glycosylated haemoglobin did not improve with either dose of vitamin D-3. On covariate analysis, systolic blood pressure was significantly lower in both treatment arms than in the placebo group at 8 weeks (placebo 146.4 mmHg, 100,000 IU 141.4 mmHg [p = 0.04 vs placebo], 200,000 IU 136.8 mmHg [p = 0.03 vs placebo]). B-type natriuretic peptide levels were significantly lower in the 200,000 IU group by 16 weeks (placebo 34 pg/ml, 200,000 IU 21 pg/ml, p = 0.02). No significant excess of adverse effects was noted in the treatment arms.

    High-dose vitamin D-3 improved systolic blood pressure and B-type natriuretic peptide levels, but not endothelial function, insulin resistance or glycosylated haemoglobin in patients with type 2 diabetes.

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    Original languageEnglish
    Pages (from-to)2112-2119
    Number of pages8
    JournalDiabetologia
    Volume53
    Issue number10
    DOIs
    Publication statusPublished - Oct 2010

    Keywords

    • Blood pressure
    • Diabetes mellitus
    • Endothelial function
    • Randomised controlled trial
    • Vitamin D
    • PLACEBO-CONTROLLED TRIAL
    • D SUPPLEMENTATION
    • HEART-FAILURE
    • NATRIURETIC PEPTIDE
    • CARDIOVASCULAR-DISEASE
    • MYOCARDIAL-INFARCTION
    • INSULIN-RESISTANCE
    • BLOOD-PRESSURE
    • D DEFICIENCY
    • 25-HYDROXYVITAMIN-D

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