Chunhua Wu1, Shanhu Qiu1, Xiangyun Zhu1, Ling Li2. 1. Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, China. 2. Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Medical School, Southeast University, China. Electronic address: li-ling76@hotmail.com.
Abstract
INTRODUCTION: Low vitamin D status has been found to be associated with impaired glycemic control in patients who suffer from type 2 diabetes; however, whether vitamin D supplementation is associated with improved glycemic status remains controversial. The aim of this study was to summarize evidence from randomized controlled trials (RCTs) to assess the efficacy of vitamin D supplementation in reducing glycosylated haemoglobinA1c (HbA1c) and fasting blood glucose (FBG) levels. MATERIALS/ METHODS: We searched PubMed, Web of Science and the Cochrane Library for reports published up to March 2017. We selected parallel RCTs investigating the effect of vitamin D or vitamin D analogues on HbA1c or FBG levels in type 2 diabetes patients. Cohen's d was calculated to represent the standardized mean difference (SMD) for each study, and the SMDs with 95%confidence intervals (CIs) were pooled using a random effects model. RESULTS: Twenty-four studies were included that evaluated HbA1c levels and 18 studies were included that evaluated FBG levels. Meta-analyses showed that vitamin D supplementation was associated with reduced HbA1c levels (standardized mean difference (SMD) -0.25 [-0.45 to -0.05]) but had no influence on FBG levels (SMD -0.14 [-0.31 to 0.03]). However, the subgroup analyses suggested that vitamin D supplementation was associated with reduced HbA1c levels (SMD -0.39 [-0.67 to -0.10]) and FBG (SMD -0.27 [-0.46 to -0.07]) among patients with 25-hydroxyvitamin D (25(OH) D) deficiency at baseline. Significantly reduced HbA1c levels were also observed in association with vitamin D supplementation in the subgroup including type 2 diabetes patients with a body mass index (BMI) <30kg m-2 (SMD -0.30 [-0.54 to -0.07]). CONCLUSIONS: Vitamin D supplementation could be effective at improving glycemic control in vitamin D deficient or non-obese type 2 diabetes patients.
INTRODUCTION: Low vitamin D status has been found to be associated with impaired glycemic control in patients who suffer from type 2 diabetes; however, whether vitamin D supplementation is associated with improved glycemic status remains controversial. The aim of this study was to summarize evidence from randomized controlled trials (RCTs) to assess the efficacy of vitamin D supplementation in reducing glycosylated haemoglobinA1c (HbA1c) and fasting blood glucose (FBG) levels. MATERIALS/ METHODS: We searched PubMed, Web of Science and the Cochrane Library for reports published up to March 2017. We selected parallel RCTs investigating the effect of vitamin D or vitamin D analogues on HbA1c or FBG levels in type 2 diabetespatients. Cohen's d was calculated to represent the standardized mean difference (SMD) for each study, and the SMDs with 95%confidence intervals (CIs) were pooled using a random effects model. RESULTS: Twenty-four studies were included that evaluated HbA1c levels and 18 studies were included that evaluated FBG levels. Meta-analyses showed that vitamin D supplementation was associated with reduced HbA1c levels (standardized mean difference (SMD) -0.25 [-0.45 to -0.05]) but had no influence on FBG levels (SMD -0.14 [-0.31 to 0.03]). However, the subgroup analyses suggested that vitamin D supplementation was associated with reduced HbA1c levels (SMD -0.39 [-0.67 to -0.10]) and FBG (SMD -0.27 [-0.46 to -0.07]) among patients with 25-hydroxyvitamin D (25(OH) D) deficiency at baseline. Significantly reduced HbA1c levels were also observed in association with vitamin D supplementation in the subgroup including type 2 diabetespatients with a body mass index (BMI) <30kg m-2 (SMD -0.30 [-0.54 to -0.07]). CONCLUSIONS:Vitamin D supplementation could be effective at improving glycemic control in vitamin D deficient or non-obese type 2 diabetespatients.
Authors: Roger Bouillon; Claudio Marcocci; Geert Carmeliet; Daniel Bikle; John H White; Bess Dawson-Hughes; Paul Lips; Craig F Munns; Marise Lazaretti-Castro; Andrea Giustina; John Bilezikian Journal: Endocr Rev Date: 2019-08-01 Impact factor: 19.871
Authors: Edith Angellotti; David D'Alessio; Bess Dawson-Hughes; Jason Nelson; Robert M Cohen; Amalia Gastaldelli; Anastassios G Pittas Journal: J Endocr Soc Date: 2018-02-26