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.
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 levels 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 significantly elevated concentrations of mono-n-butyl phthalate (MBP; 644.3 vs. 129.6 microg/g creatinine, p < 0.001) and mono-2-ethylhexyl phthalate (MEHP; 565.7 vs. 5.7 microg/g creatinine, p < 0.001). fT was significantly lower (8.4 vs. 9.7 microg/g creatinine, p = 0.019) in exposed workers than in unexposed 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).


CONCLUSIONS
We observed a modest and significant reduction of serum fT in workers with higher levels of urinary MBP and MEHP compared with unexposed workers.
Pan
Guowei
G
Department of Environmental Epidemiology, Liaoning Provincial Center for Disease Prevention and Control, Shenyang, People's Republic of China.
Hanaoka
Tomoyuki
T
Yoshimura
Mariko
M
Zhang
Shujuan
S
Wang
Ping
P
Tsukino
Hiromasa
H
Inoue
Koichi
K
Nakazawa
Hiroyuki
H
Tsugane
Shoichiro
S
Takahashi
Ken
K
D000328:Adult; D000395:Air Pollutants, Occupational / Q000633:toxicity*; D002681:China; D003430:Cross-Sectional Studies; D003993:Dibutyl Phthalate / Q000633:toxicity*; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives / Q000633:toxicity* / Q000652:urine; D004784:Environmental Monitoring; D004958:Estradiol / Q000097:blood; D005430:Floors and Floorcoverings; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis; D010795:Phthalic Acids / Q000652:urine; D010968:Plasticizers / Q000633:toxicity*; D011143:Polyvinyl Chloride; D013739:Testosterone / Q000097:blood*
D000395:Air Pollutants, Occupational; D010795:Phthalic Acids; D010968:Plasticizers; D003993:Dibutyl Phthalate; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D011143:Polyvinyl Chloride; D004051:Diethylhexyl Phthalate; C016599:mono-(2-ethylhexyl)phthalate; C028577:monobutyl phthalate