Background: Phthalate exposures might alter male reproductive health, but human evidence remains limited and inconsistent. Occupational settings often have consistently high exposures from known sources, providing a basis for developing risk reduction strategies and interventions.
Objectives: Evaluate dose-response relationships between phthalate exposures in professional printers (urinary metabolites) and male reproductive hormones, which were examined twice in one working week for workweek value (mean) and change within-week (ratio) responses.
Methods: Occupational biomonitoring of 59 male printers was used to assess exposures to 18 phthalates by measuring 35 urinary phthalate metabolites. Blood samples collected on the first and last day of the workweek were analyzed for total testosterone, calculated free testosterone (cFT), bioavailable testosterone (BioT), measured free testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone, follicle-stimulating hormone, prolactin, estradiol (E2), and inhibin B (INHB). Multiple linear covariate-adjusted regressions were used to evaluate the dose-response relationship.
Results: cFT hormonal workweek response was negatively associated with di-n-butyl phthalate (DnBP) metabolites while SHBG was positively associated with di-ethyl-hexyl phthalate (DEHP) metabolites. BioT and E2 withinweek responses were negatively associated with the DiBP metabolite mono-2-hydroxy-isobutyl phthalate (2OH-MiBP). Overall, ten low-molecular-weight phthalate metabolite concentrations were positively associated with INHB, while eight high-molecular-weight phthalates metabolite concentrations were negatively associated with FSH. Occupational exposure to these phthalates was elevated, as median concentrations of their metabolites were between 2- to 7-fold higher than general population levels.
Conclusions: Occupational exposures to certain phthalates in professional printers were associated with hormonal patterns, indicative of antiandrogenic reproductive disturbance and potential alteration of the HPG-axis.
