Age-specific vaginal microecological dysbiosis associated with HPV infection: a large-scale cross-sectional study with targeted functional sequencing validation

Purpose The vaginal microecological parameters as a critical immune barrier, yet their age-dependent interaction with Human papillomavirus (HPV) infection remains poorly understood. To characterize age-dependent vaginal microbiota composition and function across the female lifespan, and to evaluate the selective impact of HPV infection on microecological stability and infectious risk. Methods A total of 23,672 women were stratified into four age groups (18–34, 35–44, 45–55, and >55 years). Vaginal microecology was evaluated using Gram-staining, pH, hydrogen peroxide (H 2 O 2 ), leukocyte esterase, and sialidase assays. HPV genotyping was performed in 2,116 women. Statistical analysis employed univariate screening, LASSO regression for variable selection, and multivariate logistic regression to identify independent microecological risk factors, with Benjamini-Hochberg false discovery rate (FDR) correction applied across all tests. A targeted subset (n = 88) underwent 16S rRNA sequencing with differential taxa analysis using LEfSe and Random Forest, as well as BugBase phenotype prediction and COG/KEGG pathway analysis, to validate age-specific HPV-microbiome interactions. Results Normal flora prevalence declined linearly with age (78.7% vs. 48.8% postmenopause, q