(10-09-14) Effect of Vitamin D3 Supplementation on Improving Glucose Homeostasis and Preventing Diabetes: A Systematic Review and Meta-Analysis

Seida JC1, Mitri J, Colmers IN, Majumdar SR, Davidson MB, Edwards AL, Hanley DA, Pittas AG, Tjosvold L, Johnson JA.
Author information

Abstract
Context: Observational studies report consistent associations between low vitamin D concentration and increased glycemia and risk of type 2 diabetes, but results of randomized controlled trials (RCTs) are mixed. Objective: To systematically review RCTs that report on the effects of vitamin D supplementation on glucose homeostasis or diabetes prevention. Data Sources: MEDLINE, EMBASE, SCOPUS, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment, and Science Citation Index from inception to June 2013. Study Selection: Trials that compared vitamin D3 supplementation with placebo or a non-vitamin D supplement in adults with normal glucose tolerance, prediabetes, or type 2 diabetes. Data Extraction and Synthesis: Two reviewers collected data and assessed trial quality using the Cochrane Risk of Bias tool. Random effects models were used to estimate mean differences (MD) and odds ratios (OR). The main outcomes of interest were HOMA-IR, HOMA-B, hemoglobin A1c levels, fasting blood glucose, incident diabetes, and adverse events. Data Synthesis: Thirty-five trials (43,407 patients) with variable risk of bias were included. Vitamin D had no significant effects on insulin resistance (HOMA-IR: MD, -0.04; 95%CI, -0.30 to 0.22, I2=45%), insulin secretion (HOMA-B: MD, 1.64; 95%CI, -25.94 to 29.22, I2=40%), or A1c (MD, -0.05%; 95%CI, -0.12 to 0.03, I2=55%) compared with controls. Four RCTs reported on progression to new diabetes and found no effect of vitamin D (OR, 1.02; 95%CI, 0.94 to 1.10, I2=0%). Adverse events were rare, and there was no evidence of publication bias. Conclusions: Evidence from available trials shows no effect of vitamin D3 supplementation on glucose homeostasis or diabetes prevention. Definitive conclusions may be limited in the context of the moderate degree of heterogeneity, variable risk of bias, and short-term follow-up duration of the available evidence to date.

Source: J Clin Endocrinol Metab. 2014 Jul 25:jc20142136. [Epub ahead of print]

News

---

In evidenza

"L'informazione presente nel sito serve a migliorare, e non a sostituire, il rapporto medico-paziente."

Per coloro che hanno problemi di salute si consiglia di consultare sempre il proprio medico curante.