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-ControlleReport as inadecuate




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-Controlle - Download this document for free, or read online. Document in PDF available to download.

Objectives

To examine whether combined vitamin D and calcium supplementation improves insulin sensitivity, insulin secretion, β-cell function, inflammation and metabolic markers.

Design

6-month randomized, placebo-controlled trial.

Participants

Ninety-five adults with serum 25-hydroxyvitamin D 25OHD ≤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.

Intervention

Daily calcium carbonate 1,200 mg and cholecalciferol 2,000–6,000 IU to target 25OHD >75 nmol-L or matching placebos for 6 months.

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.

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 25OHD 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.

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.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12609000043235



Author: Claudia Gagnon , Robin M. Daly, André Carpentier, Zhong X. Lu, Catherine Shore-Lorenti, Ken Sikaris, Sonia Jean, Peter R. Ebelin

Source: http://plos.srce.hr/



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