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Effects of combined calcium and vitamin D supplementation on insulin secretion, insulin sensitivity and β-cell function in multi-ethnic vitamin D-deficient adults at risk for type 2 diabetes: a pilot randomized, placebo-controlled trial.
- Source :
-
PloS one [PLoS One] 2014 Oct 09; Vol. 9 (10), pp. e109607. Date of Electronic Publication: 2014 Oct 09 (Print Publication: 2014). - Publication Year :
- 2014
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Abstract
- Objectives: To examine whether combined vitamin D and calcium supplementation improves insulin sensitivity, insulin secretion, β-cell function, inflammation and metabolic markers.<br />Design: 6-month randomized, placebo-controlled trial.<br />Participants: Ninety-five adults with serum 25-hydroxyvitamin D [25(OH)D] ≤55 nmol/L at risk of type 2 diabetes (with prediabetes or an AUSDRISK score ≥15) were randomized. Analyses included participants who completed the baseline and final visits (treatment n = 35; placebo n = 45).<br />Intervention: Daily calcium carbonate (1,200 mg) and cholecalciferol [2,000-6,000 IU to target 25(OH)D >75 nmol/L] or matching placebos for 6 months.<br />Measurements: Insulin sensitivity (HOMA2%S, Matsuda index), insulin secretion (insulinogenic index, area under the curve (AUC) for C-peptide) and β-cell function (Matsuda index x AUC for C-peptide) derived from a 75 g 2-h OGTT; anthropometry; blood pressure; lipid profile; hs-CRP; TNF-α; IL-6; adiponectin; total and undercarboxylated osteocalcin.<br />Results: Participants were middle-aged adults (mean age 54 years; 69% Europid) at risk of type 2 diabetes (48% with prediabetes). Compliance was >80% for calcium and vitamin D. Mean serum 25(OH)D concentration increased from 48 to 95 nmol/L in the treatment group (91% achieved >75 nmol/L), but remained unchanged in controls. There were no significant changes in insulin sensitivity, insulin secretion and β-cell function, or in inflammatory and metabolic markers between or within the groups, before or after adjustment for potential confounders including waist circumference and season of recruitment. In a post hoc analysis restricted to participants with prediabetes, a significant beneficial effect of vitamin D and calcium supplementation on insulin sensitivity (HOMA%S and Matsuda) was observed.<br />Conclusions: Daily vitamin D and calcium supplementation for 6 months may not change OGTT-derived measures of insulin sensitivity, insulin secretion and β-cell function in multi-ethnic adults with low vitamin D status at risk of type 2 diabetes. However, in participants with prediabetes, supplementation with vitamin D and calcium may improve insulin sensitivity.<br />Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12609000043235.
- Subjects :
- Adiponectin metabolism
Adult
Aged
Blood Glucose metabolism
C-Peptide biosynthesis
C-Reactive Protein metabolism
Diabetes Mellitus, Type 2 metabolism
Diabetes Mellitus, Type 2 physiopathology
Female
Humans
Insulin biosynthesis
Insulin pharmacology
Insulin Resistance
Insulin-Secreting Cells cytology
Insulin-Secreting Cells drug effects
Insulin-Secreting Cells metabolism
Interleukin-6 metabolism
Male
Middle Aged
Osteocalcin metabolism
Pilot Projects
Prediabetic State metabolism
Prediabetic State physiopathology
Tumor Necrosis Factor-alpha metabolism
Vitamin D Deficiency metabolism
Vitamin D Deficiency physiopathology
Calcium, Dietary administration & dosage
Cholecalciferol administration & dosage
Diabetes Mellitus, Type 2 prevention & control
Dietary Supplements
Prediabetic State diet therapy
Vitamin D Deficiency diet therapy
Subjects
Details
- Language :
- English
- ISSN :
- 1932-6203
- Volume :
- 9
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- PloS one
- Publication Type :
- Academic Journal
- Accession number :
- 25299668
- Full Text :
- https://doi.org/10.1371/journal.pone.0109607