Age-specific vaginal microecological dysbiosis associated with HPV infection: a large-scale cross-sectional study...

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.

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 (H₂O₂), 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.

Normal flora prevalence declined linearly with age (78.7% vs. 48.8% postmenopause, q<0.001), while microbial diversity peaked during perimenopause. HPV infection was selectively associated with increased bacterial vaginosis (BV) (41.58% vs. 36.46%, q=0.032) and sialidase activity (28.14% vs. 21.69%, q=0.002), but decreased vulvovaginal candidiasis (VVC, 10.57% vs. 15.66%, q=0.003). Functional analyses revealed HPV-driven anaerobic enrichment (Gardnerella, Atopobium) and profound metabolic reprogramming specifically in women aged 35-44 years, marked by upregulation of lipopolysaccharide biosynthesis (fold change [FC] = 37.3, q = 0.028), arachidonic acid metabolism (FC = 33.3, q = 0.038), and NOD-like receptor signaling (FC = 62.1, q < 0.001), with concurrent apoptosis suppression (FC = 0.35, q = 0.046). Age-stratified risk modeling identified loss of H₂O₂-producing Lactobacilli as the strongest HPV risk factor in younger women (18-34 years, adjusted odds ratio [aOR] = 0.59), whereas BV and sialidase dominated in midlife (35-44 years, aOR = 1.64); no significant risk factors emerged postmenopause.

HPV infection selectively remodels vaginal microbiota composition and metabolic function in an age-dependent manner, with midlife women (35-44 years) representing a critical window for microbiota-based HPV prevention strategies.