title: Effects of vitamin D supplementation on glycated haemoglobin and fasting glucose levels in hypertensive patients: a randomized controlled trial.
abstract: To investigate the efficacy of vitamin D supplementation on glycaemic control.
  
  
  
  The Styrian Vitamin D Hypertension Trial was a single-centre, double-blind, placebo-controlled study conducted between 2011 and 2014 at the Medical University of Graz, Austria. We enrolled 200 people with arterial hypertension and 25-hydroxyvitamin D [25(OH)D] concentrations <30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D or placebo per day for 8 weeks. The present study was a post hoc analysis that incorporated an analysis of covariance (ancova) approach, while adjusting for baseline differences.
  
  
  
  A total of 185 participants [mean ± standard deviation age, 60.1 ± 11.3 years; 47% women; mean 25(OH)D 21.2 ± 5.6 ng/mL, mean glycated haemoglobin (HbA1c) 44.8 ± 11.8 mmol/mol and mean body mass index 30.4 ± 5.4 kg/m(2) ] completed the trial. ancova showed a mean treatment effect [95% confidence interval (CI)] on HbA1c of -3.52 (-6.7 to -0.34) mmol/mol (p = .045). There was no difference in fasting glucose -4.7 mg/dL (95% CI -16.3 to 6.9; p = .426).
  
  
  
  Vitamin D supplementation in obese hypertensive patients with low 25(OH)D reduces HbA1c levels. This finding warrants further investigation into potential vitamin D effects on glucose homeostasis.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria. martin.gruebler@gmx.net.|Department of Cardiology, Swiss Cardiovascular Center Bern, Bern University Hospital, Bern, Switzerland. martin.gruebler@gmx.net.
authors.forename: M R
authors.initials: MR
authors.lastname: Grübler
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Gaksch
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Kienreich
authors.affiliation: Department of Cardiology, Medical University of Graz, Graz, Austria.
authors.forename: N
authors.initials: N
authors.lastname: Verheyen
authors.affiliation: Department of Cardiology, Medical University of Graz, Graz, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Schmid
authors.affiliation: Department of Radiology, Dalio Institute of Cardiovascular Imaging, New York-Presbyterian Hospital and the Weill Cornell Medical College, New York.
authors.forename: B
authors.initials: B
authors.lastname: Ó Hartaigh
authors.affiliation: Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Richtig
authors.affiliation: Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Scharnagl
authors.affiliation: Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Meinitzer
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Fahrleitner-Pammer
authors.affiliation: Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.|Synlab Academy, Synlab Services GmbH, Mannheim, Germany.|Medical Clinic V (Nephrology, Hypertensiology, Rheumatology, Endocrinolgy, Diabetology), Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: März
authors.affiliation: Department of Cardiology, Medical University of Graz, Graz, Austria.|Specialist Clinic for Rehabilitation Bad Aussee, Bad Aussee, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Tomaschitz
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria.|Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Pilz
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D019587:Dietary Supplements; D004311:Double-Blind Method; D005215:Fasting / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications* / Q000178:diet therapy; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications / Q000178:diet therapy; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology*; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications* / Q000178:diet therapy*
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: cardiovascular disease; randomised trial; type 2 diabetes