Mixture analysis of urinary parabens and their associations with reproductive hormones in iranian women

While parabens are widely used, concerns exist regarding their potential to impair reproductive health through endocrine disruption. However, evidence on impacts of paraben mixtures remains insufficient, particularly regarding hormonal regulation in women. We conducted a cross-sectional study of 84 women of reproductive age (18–45 years) at Imam Reza Hospital, Kermanshah. Urinary concentrations of methylparaben (MePB), ethylparaben (EtPB), propylparaben (PrPB), and butylparaben (BuPB) were quantified via GC-MS and adjusted for specific gravity, while serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin were measured using ELISA. We employed multivariable linear regression and exploratory relative-weight analysis to evaluate mixture-based associations, supplemented by non-carcinogenic risk assessment. MePB was most abundant, whereas BuPB accounted for 65.1% of cumulative estrogenic activity (EEQ). Mixture models revealed significant associations exclusively with LH ( n = 35), with PrPB (45%, p = 0.021) and EtPB (24%, p = 0.032) showing positive contributions, and BuPB (23%, p = 0.033) and MePB (8%, p = 0.037) showing inverse contributions; no significant associations were observed for FSH or prolactin. Although hazard quotients remained below 1 (95th percentile HI = 0.0998) and Monte Carlo simulations confirmed negligible non-carcinogenic risk, paraben mixtures may be related to hormonal levels. These findings highlight the subtle endocrine-disrupting potential of parabens at these levels.