Do Biomarkers and Molecular Evidence Matter? New Evidence of Ties Between Endocrine Disrupting Chemi
Gathering molecular information matters. Consider the information set out in a January 7, 2016 article at europa.eu that summarizes a new medical journal on “endocrine disrupting chemicals” and “subfertility, the inability to conceive for a prolonged period.” The summary article explains:
“The researchers measured biomarkers of EDC exposure and key fertility parameters in 163 men recruited through four fertility clinics in Belgium. Semen samples were analysed following the guidelines of the World Health Organization, using a total motility count (TMC) of 20 million as a threshold value for normality.
The researchers recruited ‘cases’ – male partners of couples who were experiencing involuntary infertility– and ‘controls’ – male partners of couples with a documented or suspected female cause of infertility, or sperm donors.
Patients were assigned to the case group when two semen samples (collected at least one week apart) had a TMC less than 20 million. If both samples had a TMC of 20 million or above, the patient was assigned to the control group. Of the 163 patients, 80 met the criteria to be controls and 40 to be cases. Blood and urine samples were also taken to analyse levels of EDCs and sex hormones.
The study revealed associations between exposure and subfertility for a number of compounds, including: ***
Brominated flame retardants (BDE209): Detectable levels of BDE209 in serum were associated with a 7.2 increased risk of subfertility and a 33% reduction in sperm motility.”
The full medical journal article is online (paywall). The abstract explains:
Dioxins, PCBs, chlorinated pesticides, brominated flame retardants, bisphenol A, triclosan, perfluorinated compounds and phthalates are known as endocrine disrupting chemicals (EDCs).
The aim of our study was to investigate whether higher exposure to EDCs is associated with increased subfertility in men.
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.
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.
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.”