Blood Vitamin C Level in Type 2 Diabetes Mellitus Patients:A Meta-Analysis

TIAN Yalan; AN Weifeng; CUI Lingling; YAN Yan; CHEN Wei

doi:10.3969/j.issn.1004-437X.2026.09.009

Abstract：Objective To explore the levels of vitamin C(VC)in the blood of type 2 diabetes mellitus(T2DM)patients,and to provide reference for the etiology and prevention of T2DM.Methods A comprehensive search was conducted through the Web of Science,PubMed,Wanfang,and China National Knowledge Infrastructure(CNKI)databases for literature published between January 1,1980,and February 26,2024.The Newcastle-Ottawa scale(NOS)was used to assess the quality of the included literature.Meta-analysis was performed on the included literature using Stata 15.1 statistical software.Results A total of 11 case-control studies were ultimately included,involving 424 cases in the patient group and 393 in the control group.The meta-analysis results showed that the blood VC levels in the patient group were lower than those in the control group(WMD=-23.76,95％CI:-30.24--17.28,P＜0.001).Meta-regression analysis indicated that the source of controls had a statistically significant impact on the heterogeneity of blood VC levels among studies(P＜0.05).Subgroup analysis revealed that in studies with different continents,countries,publication years,sources of controls,blood sample types,sample sizes,blood VC measurement methods,and whether VC supplements were taken,the blood VC levels in the patient group were significant lower than those in the control group(P＜0.05).Sensitivity analysis showed that the included literature was relatively stable.Begg's test suggested no publication bias in this study(Z=1.25,P=0.213).Conclusion The blood VC levels of T2DM patients are lower than those of healthy controls.It is speculated that low VC intake might be one of the causes of T2DM,and adequate supplementation of VC might decrease the risk of T2DM.