Urinary concentrations of organophosphate esters in relation to semen quality: A cross-sectional study

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in consumer products. Toxicological studies have indicated that OPEs may affect male reproductive health, but human evidence is inconclusive. In this study, we explored associations of individual and mixtures of OPE exposure with semen quality among 1015 Chinese men from an infertility clinic. After adjusting for potential confounders, we observed that higher diphenyl phosphate (DPHP) and [Bis(2-methylphenyl) phosphate (BMPP)] exposure was associated with increased odds ratios (ORs) of having below-reference total sperm count. Higher bis (2-butoxyethyl) phosphate (BBOEP) exposure was associated with increased ORs of having below-reference progressive motility and total motility. For semen quality parameters modeled as continuous outcomes, inverse associations with individual OPE were still observed. In addition, urinary 1-hydroxy-2-propyl bis (1-chloro-2-propyl) phosphate (BCIPHIPP) concentrations were inversely associated with the percentage of normal morphology while positively associated with the percentage of abnormal heads. Quantile g-computation regression analyses showed that exposure to higher OPE mixtures was associated with lower total sperm motility and normal morphology. Our results indicated that both individual and mixtures of OPE exposure were associated with reduced semen quality.