Decreased Serum Free Testosterone in Workers Exposed to High Levels of Di-n-butyl Phthalate (DBP) and Di-2-ethylhexyl Phthalate (DEHP):A Cross-Sectional Study in China

摘要

BACKGROUND:Observations of adverse developmental and reproductive effects in laboratory animals and wildlife have fueled increasing public concern regarding the potential for various chemicals to impair human fertility.OBJECTIVE:Our objective in this study was to assess the effect of occupational exposure to high lev-els of phthalate esters on the balance of gonadotropin and gonadal hormones including luteinizing hormone,follicle-stimulating hormone,free testosterone (fT),and estradiol.METHODS:We examined urine and blood samples of 74 male workers at a factory producing unfoamed polyvinyl chloride flooring exposed to di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) and compared them with samples from 63 male workers from a construction company,group matched for age and smoking status.RESULTS:Compared to the unexposed workers,the exposed workers had substantially and signifi-cantly elevated concentrations of mono-n-butyl phthalate (MBP;644.3 vs.129.6 mu g/g creatinine,p < 0.001) and mono-2-ethylhexyl phthalate (MEHP;565.7 vs.5.7 ug/g creatinine,p < 0.001).fT was significantly lower (8.4 vs.9.7 mu g/g creatinine,p=0.019) in exposed workers than in unex-posed workers.fT was negatively correlated to MBP (r=-0.25,p=0.03) and MEHP (r=-0.19,p=0.095) in the exposed worker group.Regression analyses revealed that fT decreases significantly with increasing total phthalate ester score (the sum of quartiles of MBP and MEHP;r=-0.26,p=0.002).CONCLUSION:We observed a modest and significant reduction of serum fT in workers with higher levels of urinary MBP and MEHP compared with unexposed workers.