Are endocrine disrupting chemicals responsible for downward trends in male fertility?
A growing body of evidence suggests that endocrine-disrupting compounds (EDCs) are contributing to declines in fertility.
BACKGROUND: Dioxins, PCBs, chlorinated pesticides, brominated flame retardants, bisphenol A, triclosan, perfluorinated compounds and phthalates are known as endocrine disrupting chemicals (EDCs).
OBJECTIVES: 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.
Human exposure to endocrine disrupting chemicals and fertility: A case-control study in male subfertility patients, NCBI PMID: 26292060, 2015 Nov.
Are endocrine disrupting chemicals responsible for downward trends in male fertility?, ec.europa, 7 January 2016.
Fracking involves hundreds of toxins that may pose serious ills and many more that remain unstudied
A systematic evaluation of chemicals in hydraulic-fracturing fluids and wastewater for reproductive and developmental toxicity, Journal of Exposure Science and Environmental Epidemiology, doi:10.1038/jes.2015.81, 6 January 2016.
Hydraulic-fracturing fluids and wastewater from unconventional oil and natural gas development contain hundreds of substances with the potential to contaminate drinking water.
Challenges to conducting well-designed human exposure and health studies include limited information about likely etiologic agents.
We found a number of things that shouldn’t be in the water
said Zacariah Hildenbrand – researcher with Inform Environmental – to the huffingtonpost.
We systematically evaluated 1021 chemicals identified in hydraulic-fracturing fluids (n=925), wastewater (n=132), or both (n=36) for potential reproductive and developmental toxicity to triage those with potential for human health impact.
We searched the REPROTOX database using Chemical Abstract Service registry numbers for chemicals with available data and evaluated the evidence for adverse reproductive and developmental effects.
Next, we determined which chemicals linked to reproductive or developmental toxicity had water quality standards or guidelines.
Toxicity information was lacking for 781 (76%) chemicals.
Of the remaining 240 substances, evidence suggested reproductive toxicity for 103 (43%), developmental toxicity for 95 (40%), and both for 41 (17%).
Of these 157 chemicals, 67 had or were proposed for a federal water quality standard or guideline. Our systematic screening approach identified a list of 67 hydraulic fracturing-related candidate analytes based on known or suspected toxicity.
Some previous research suggest that even tiny doses of those chemicals released by fracking could pose serious health risks to pregnant women and developing fetuses, babies and young children.
Incorporation of data on potency, physicochemical properties, and environmental concentrations could further prioritize these substances for future drinking water exposure assessments or reproductive and developmental health studies.
Elucidating hydraulic fracturing impacts on groundwater quality using a regional geospatial statistical modeling approach, sciencedirect, 2015.
Chemical Analysis of Wastewater from Unconventional Drilling Operations, mdpi, 15 April 2015.
This systematic review found that the overall risk of major birth defects remains low
The risk of major cardiac malformations associated with paroxetine use during the first trimester of pregnancy: A systematic review and meta-analysis, British Journal of Clinical Pharmacology, DOI: 10.1111/bcp.12849, Jan 2016.
Aims The aim of this study was to perform an up-to-date meta-analysis on the risk of cardiac malformations associated with gestational exposure to paroxetine, taking into account indication, study design, and reference category.
Method A systematic review of studies published between 1966 and November 2015 was conducted using EMBASE and MEDLINE. Studies reporting major malformations with first trimester exposure to paroxetine were included. Potentially relevant articles were assessed and relevant data extracted to calculate risk estimates. Outcomes included any major malformations, and major cardiac malformations. Pooled odds ratios and 95% confidence intervals were calculated using random-effects models.
Results Twenty-three studies were included. Compared to non-exposure to paroxetine, first trimester use of paroxetine was associated with an increased risk of any major congenital malformations combined (pooled OR 1.23, 95% CI 1.10, 1.38; n=15 studies); major cardiac malformations (pooled OR 1.28, 95% CI 1.11, 1.47; n=18 studies), specifically bulbus cordis anomalies and anomalies of cardiac septal closure (pooled OR 1.42, 95% CI 1.07, 1.89; n=8 studies), atrial septal defects (pooled OR 2.38, 95% CI 1.14, 4.97; n=4 studies), and right ventricular outflow track defect (pooled OR 2.29, 95% CI 1.06, 4.93; n=4 studies). Although the estimates varied depending on the comparator group, study design and malformation detection period, a trend towards increased risk was observed.
Conclusions Paroxetine use during the first trimester of pregnancy is associated with an increased risk of any major congenital malformations and cardiac malformations. The increase in risk is not dependent on the study method or population.
BDNF DNA methylation in the blood may represent a novel clinical epigenetic biomarker for the early detection of psychopathology
Researchers previous study showed that environmentally relevant doses of BPA given to female mice during pregnancy induce lasting epigenetic disruption in the prefrontal cortex and hypothalamus of the offspring and that these changes are sex-specific.
Early-life adversity increases the risk for psychopathology in later life. The underlying mechanism(s) is unknown, but epigenetic variation represents a plausible candidate. Early-life exposures can disrupt epigenetic programming in the brain, with lasting consequences for gene expression and behavior. This evidence is primarily derived from animal studies, with limited study in humans due to inaccessibility of the target brain tissue. In humans, although there is evidence for DNA methylation changes in the peripheral blood of psychiatric patients, a fundamental question remains as to whether epigenetic markers in the blood can predict epigenetic changes occurring in the brain.
We used in utero bisphenol A (BPA) exposure as a model environmental exposure shown to disrupt neurodevelopment and exert long-term effects on behavior in animals and humans. We show that prenatal BPA induces lasting DNA methylation changes in the transcriptionally relevant region of the Bdnf gene in the hippocampus and blood of BALB/c mice and that these changes are consistent with BDNF changes in the cord blood of humans exposed to high maternal BPA levels in utero. Our data suggest that BDNF DNA methylation in the blood may be used as a predictor of brain BDNF DNA methylation and gene expression as well as behavioral vulnerability induced by early-life environmental exposure. Because BDNF expression and DNA methylation are altered in several psychiatric disorders that are associated with early-life adversity, including depression, schizophrenia, bipolar disorder, and autism, BDNF DNA methylation in the blood may represent a novel biomarker for the early detection of psychopathology.
Advances in medicine have propelled health care to new heights and a vast array of diagnostic tests and drug therapies is now available. But are we getting too much of a good thing?
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An increasing number of doctors now say that sometimes, “less is more” when it comes to medical interventions. Some doctors are concerned that resources are being wasted on the “worried well” and that the ever-expanding definition of how we define “disease” has been influenced by vested interests. Could excessive medical interventions be causing more harm than good?