Characteristic of experimental trials included in the meta-analysis.

FPG: fasting plasma glucose; vitE: vitamin E; mixed tocopherols: 60%γ-,25% δ- and 15% α-tocopherol; HbA1c: glycated hemoglobin; USA: United States of America; UK: The United Kingdom; T:treatment group; C: control group; C1: crossover design; P: Parallel design.FPG：空腹血浆葡萄糖（fasting plasma glucose）；vitE：维生素E（vitamin E）；混合生育酚（mixed tocopherols）：组成为60%γ-生育酚、25%δ-生育酚及15%α-生育酚；HbA1c：糖化血红蛋白（glycated hemoglobin）；USA：美利坚合众国（United States of America）；UK：大不列颠及北爱尔兰联合王国（The United Kingdom）；T：试验组（treatment group）；C：对照组（control group）；C1：交叉设计（crossover design）；P：平行设计（Parallel design）。