Vaginal polycyclic aromatic hydrocarbons (PAHs), HPV infection, and vaginal microbiome in firefighters: A cross-sectional study.

Female firefighters are routinely exposed to combustion-derived toxicants, yet the reproductive health implications of this exposure are largely unknown. We investigated whether polycyclic aromatic hydrocarbons (PAHs) are detectable in the vaginal tract of female firefighters and whether these contaminants are linked to high-risk human papillomavirus (HPV) infection and vaginal microbiome alterations. In this cross-sectional study 49 female firefighters and 51 community controls self-collected vaginal swabs for analysis of 16 EPA-priority PAHs, high-risk HPV, and microbial composition. All 16 PAHs were detectable and median total PAHs were 3-fold higher in firefighters than controls (p < .0001). PAH burden increased with firefighting tenure showing a strong positive correlation between high- and low-molecular-weight congeners (r = 0.85). High-risk HPV was detected in 12.2% of firefighters versus 3.9% of controls and was associated with higher PAH levels (p = 0.02). Firefighters exhibited a microbiome shift characterized by increased relative abundance of Gardnerella (r = 0.32 with total PAHs) and reduced Lactobacillus dominance. Detection of vaginal PAHs along with their associations with HPV and dysbiosis, suggests a previously unrecognized pathway by which occupational exposures may elevate cervical cancer risk. Targeted exposure reduction policies and vigilant gynecologic screening should be considered for this underserved workforce.