摘要Objective Epidemiological studies have shown that vitamin D status affects glycemic control in individuals with type 2 diabetes mellitus(T2DM).However,findings from intervention studies remain inconsistent.Therefore,a network meta-analysis was conducted to evaluate the comparative efficacy of various vitamin D supplementation strategies on glucose indicators in adults with T2DM.Methods Eligible studies published before September 12,2024,were retrieved from PubMed,EMBASE,Cochrane Library,and Web of Science.A network meta-analysis of multiple dosage strategies—low(<1,000 IU/day,LDS),medium(1,000-2,000 IU/day,MDS),high(2,000-4,000 IU/day,HDS),and extremely high(≥4,000 IU/day,EHDS)—was performed.Results The network meta-analysis of 40 RCTs indicated that,compared with placebo,vitamin D3 supplementation increased 25-hydroxyvitamin D[25-(OH)-D]levels,with pooled mean difference(MD)showing a stepwise increase from LDS to EHDS.Ranking probabilities showed a corresponding rise in 25-(OH)-D levels from LDS(46.7%)to EHDS(91.2%).EHDS reduced fasting blood glucose(FBG)relative to no treatment.LDS significantly decreased hemoglobin A1c(HbA1c),and vitamin D2 significantly affected FBG levels.MDS led to a significant change in fasting insulin(FIN)compared to both placebo(MD:-4.76;95%CI-8.91 to-0.61)and no treatment(MD:-7.30;95%CI-14.44 to-0.17).Conclusion The findings suggest that vitamin D supplementation may be a viable approach for improving glycemic control in adults with T2DM,with lower doses potentially offering benefit.The analysis also showed a dose-dependent increase in 25-(OH)-D levels.