Human exposure to endocrine disrupting chemicals and fertility: A case-control study in male subfertility patients.
BACKGROUND
Dioxins, PCBs, chlorinated pesticides, brominated flame retardants, bisphenol A, triclosan, perfluorinated compounds and phthalates are known as endocrine disrupting chemicals (EDCs).


OBJECTIVE
The aim of our study was to investigate whether higher exposure to EDCs is associated with increased subfertility in men.


METHODS
We measured biomarkers of exposure in 163 men, recruited through four fertility clinics. According to WHO guidelines, we used a total motility count (TMC) of 20 million as cut-off value. We assigned patients to the case group when two semen samples - collected at least one week apart - had a TMC<20 and to the control group when both samples had a TMC≥20. To estimate the risk of subfertility and alteration in sex hormone concentrations we used multivariable-adjusted analysis, using logistic and linear regressions, respectively.


RESULTS
For an IQR increase in serum oxychlordane, the odds ratio for subfertility was 1.98 (95% CI: 1.07; 3.69). Furthermore, men with serum levels of BDE209 above the quantification limit had an odds of 7.22 (1.03; 50.6) for subfertility compared with those having values below the LOQ. Urinary levels of phthalates and triclosan were negatively associated with inhibin B and positively with LH. Urinary bisphenol A correlated negatively with testosterone levels.


CONCLUSIONS
Our study in men showed that internal body concentrations of endocrine disrupting chemicals are associated with an increased risk of subfertility together with alterations in hormone levels. The results emphasize the importance to reduce chemicals in the environment in order to safeguard male fertility.
Environmental Risk and Health Unit, Flemish Institute for Technological Research (VITO), Mol, Belgium; Directorate of Public Health and Surveillance, Scientific Institute of Public Health, Brussels, Belgium. Electronic address: elly.denhond@wiv-isp.be.
Elly
E
Den Hond
Centre for Reproductive Medicine, University Hospital Brussels, Free University of Brussels (VUB), Brussels, Belgium.
Herman
H
Tournaye
Department of Reproductive Medicine, University Hospital Ghent, University of Ghent, Ghent, Belgium.
Petra
P
De Sutter
Department of Obstetrics & Gynaecology, Genk Institute for Fertility Technology, ZOL Hospitals, Genk, Belgium; Faculty of Medicine and Life Sciences, Hasselt University, Diepenbeek, Belgium.
Willem
W
Ombelet
Department of Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Willy
W
Baeyens
Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Wilrijk, Belgium.
Adrian
A
Covaci
Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
Bianca
B
Cox
Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium; Department of Public Health & Primary Care, Leuven University, Leuven, Belgium.
Tim S
TS
Nawrot
Department of Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Study Centre for Carcinogenesis and Primary Prevention of Cancer, Ghent University, Ghent, Belgium.
Nik
N
Van Larebeke
Division of Reproductive Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
Thomas
T
D'Hooghe
D000328:Adult; D001559:Benzhydryl Compounds / Q000097:blood; D016022:Case-Control Studies; D004147:Dioxins / Q000097:blood; D052244:Endocrine Disruptors / Q000097:blood / Q000633:toxicity*; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D005298:Fertility / Q000187:drug effects*; D006801:Humans; D007248:Infertility, Male / Q000097:blood / Q000139:chemically induced*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010575:Pesticides / Q000097:blood; D010636:Phenols / Q000097:blood; D010795:Phthalic Acids / Q000097:blood; D011078:Polychlorinated Biphenyls / Q000097:blood; D013094:Spermatozoa / Q000187:drug effects; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004147:Dioxins; D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D010575:Pesticides; D010636:Phenols; D010795:Phthalic Acids; D011078:Polychlorinated Biphenyls; C032279:phthalic acid; C006780:bisphenol A; D000098826:Bisphenol A Compounds