Vitamin D deficiency is associated with indicators of pre-diabetes including, insulin resistance, β-cell dysfunction and elevated plasma glucose with controversial findings from current trials. This study aims to investigate the long-term effect of vitamin D on glucose metabolism and insulin sensitivity in pre-diabetic and highly vitamin-deficient subjects. One hundred thirty-two participants were randomized to 30,000 IU vitamin D weekly for 6 months. Participants underwent oral glucose tolerance test (OGTT) at 3-month intervals to determine the change in plasma glucose concentration at 2 h after 75 g OGTT (2hPCG). Secondary measurements included glycated hemoglobin, fasting plasma glucose and insulin, post-prandial insulin, indices of insulin sensitivity (HOMA-IR, Matsuda Index), β-cell function (HOMA-β, glucose and insulin area under the curve (AUC), disposition and insulinogenic indices), and lipid profile. A total of 57 (vitamin D) and 75 (placebo) subjects completed the study. Mean baseline serum 25(OH) D levels were 17.0 ng/ml and 14.9 ng/ml for placebo and vitamin D group, respectively. No significant differences were observed for 2hPC glucose or insulin sensitivity indices between groups. HOMA-β significantly decreased in the vitamin D group, while area under curve for glucose and insulin showed a significant reduction in β-cell function in both groups. Additionally, HOMA-β was found to be significantly different between control and treatment group and significance persisted after adjusting for confounding factors. Vitamin D supplementation in a pre-diabetic and severely vitamin-deficient population had no effect on glucose tolerance or insulin sensitivity. The observed reduction in β-cell function in both placebo and vitamin D groups could be attributed to factors other than supplementation. NCT02098980 , 28/03/2014 ( www.clinicaltrials.gov ).

中文翻译：

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随机对照试验中维生素 D 补充剂对卡塔尔糖尿病前期患者血糖控制的影响

维生素 D 缺乏与糖尿病前期的指标有关，包括胰岛素抵抗、β 细胞功能障碍和血浆葡萄糖升高，目前的试验结果存在争议。本研究旨在调查维生素 D 对糖尿病前期和高度缺乏维生素的受试者的葡萄糖代谢和胰岛素敏感性的长期影响。132 名参与者被随机分配到每周 30,000 IU 维生素 D 组，持续 6 个月。参与者每隔 3 个月接受一次口服葡萄糖耐量试验 (OGTT)，以确定 75 g OGTT (2hPCG) 后 2 小时血浆葡萄糖浓度的变化。二次测量包括糖化血红蛋白、空腹血糖和胰岛素、餐后胰岛素、胰岛素敏感性指数（HOMA-IR、松田指数）、β细胞功能（HOMA-β、葡萄糖和胰岛素曲线下面积（AUC）、分布和胰岛素生成指数）和血脂谱。共有 57 名（维生素 D）和 75 名（安慰剂）受试者完成了这项研究。安慰剂组和维生素 D 组的平均基线血清 25（OH）D 水平分别为 17.0 ng/ml 和 14.9 ng/ml。组间 2hPC 葡萄糖或胰岛素敏感性指数未观察到显着差异。维生素 D 组的 HOMA-β 显着降低，而葡萄糖和胰岛素的曲线下面积显示两组的 β 细胞功能显着降低。此外，发现HOMA-β在对照组和治疗组之间存在显着差异，并且在调整混杂因素后显着性仍然存在。在糖尿病前期和严重缺乏维生素的人群中补充维生素 D 对葡萄糖耐量或胰岛素敏感性没有影响。在安慰剂组和维生素 D 组中观察到的 β 细胞功能下降可能归因于补充剂以外的因素。NCT02098980，2014 年 3 月 28 日（www.clinicaltrials.gov）。