中文摘要：

为观察在二甲双胍治疗糖尿病时对维生素B12的影响，探讨甲基丙二酸对诊断维生素B12缺乏的价值，本研究选取126例2型糖尿病患者进行研究，发现应用二甲双胍可导致糖尿病患者血清维生素B12水平降低[（501．62±219．98对762．86±360．92）ng／L，P〈0．01]；尿甲基丙二酸对维生素B12早期缺乏的诊断价值较高．其敏感性、特异性为81．25％、83．75％。

英文摘要：

The aim of the study was to investigate the influence of mefformin on serum vitamin B12 in patients with type 2 diabetes mellitus, and to determine the value of methy]malonic acid in the diagnosis of vitamin B12 deficiency. 126 type 2 diabetic patients were recruited. The results showed that metformin lowered serum vitamin B12 level in these patients [ （501.62±219.98 vs 762.86±360.92） ng/L,P〈0.01 ]. Urinary methylmalonic acid may be a candidate biochemical indicator for early diagnosis of vitamin B12 deficiency in the diabetic patients, with high sensitivity （ 81.25% ） and specificity （ 83.75% ）.