Peculiarities of vaginal microbiota in perimenopausal and postmenopausal women with type 2 diabetes mellitus

BACKGROUND: The changes in the vaginal microbiota and potential dysbiosis adjustment strategies in diabetic patients remain inconclusive. This study was designed to investigate the impact of Type 2 diabetes mellitus (T2DM) on the ecological dynamics of the vaginal microbiota in perimenopausal and postmenopausal women, with a focus on microbial community structure and functional homeostasis. METHODS: Vaginal secretion samples from 22 T2DM patients (DM group) and 23 healthy controls (CT group) under perimenopausal and postmenopausal conditions were analyzed via metagenomic sequencing. Alpha diversity (Observe, ACE, Shannon-Weaver, Gini-Simpson indices) and beta diversity (PCoA, NMDS) were assessed. Taxonomic profiling, LEfSe analysis, and co-occurrence network construction were performed to identify differential species and microbial interactions. Neutral community modeling evaluated stochastic vs. deterministic assembly processes. RESULTS: levels significantly influenced the relative abundance of vaginal Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus iners, showing a significant negative correlation. Co-occurrence networks revealed greater complexity and more integrated in the DM group (more triangles, lower modularity, higher node degrees, higher clustering coefficients, p < 0.0001). Neutral modeling indicated stochastic assembly (R² >0.5), with Lactobacillus species and opportunistic pathogens deviating from neutral predictions in DM. CONCLUSION: Under perimenopausal and postmenopausal conditions, T2DM disrupts vaginal microbiota homeostasis by diminishing protective Lactobacillus populations and promoting pathogen proliferation.