Further evidence that children’s exposure to bisphenol A alters brain development and triggers behavior problems
Children in the U.S. with higher levels of BPA in their bodies were more likely to have Attention Deficit Hyperactivity Disorder (ADHD), according to a study.
The research adds to evidence that children’s BPA exposure may alter brain development and lead to behavior problems such as reduced attention and hyperactivity.
ADHD is the most common behavior disorder in U.S. children, causing them to have trouble concentrating and controlling their behavior.
Abstract
Association of Bisphenol A exposure and Attention-Deficit/Hyperactivity Disorder in a national sample of U.S. children, ScienceDirect, Volume 150, October 2016, Pages 112–118, doi:10.1016/j.envres.2016.05.040.
Background
Bisphenol A (BPA) has been linked to changes in the dopamine system and development of an Attention-Deficit/Hyperactivity Disorder (ADHD) phenotype in animal models, with differing effects in males compared to females. We examined the association between urinary BPA concentrations and ADHD in a national sample of U.S. children, and whether this association differs by child sex.
Methods
We used data from the 2003–2004 National Health and Nutrition Examination Survey, a cross-sectional, nationally representative sample of the U.S. population. Participants were 8-15 years of age (N=460). Using a diagnostic interview to ascertain the presence of ADHD in the past year, multivariable logistic regression examined the link between concurrent urinary BPA concentrations and ADHD status.
Results
Of the 460 participants, 7.1% [95% CI: 4.4–11.3] met Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV) criteria for ADHD. Children who had BPA concentrations at or above the median of the sample had higher prevalence of meeting criteria for ADHD (11.2% [95% CI: 6.8–17.8]) than those with BPA concentrations below the median (2.9% [95% CI: 1.1–7.2]). Higher urinary BPA concentrations were associated with ADHD (adjusted odds ratio [aOR]: 5.68 [95% CI: 1.6–19.8] for BPA concentrations above vs. below the median). In sex-stratified analyses, these associations were stronger in boys (aOR=10.9 [95% CI: 1.4–86.0]) than in girls (aOR=2.8 [95% CI: 0.4–21.3]), although the BPA by sex interaction term was not significant (p=0.25).
Hyperactivity in children linked to plastic additive, BPA, environmentalhealthnews, June 15, 2016.
Conclusion
We found evidence that higher urinary BPA concentrations were associated with ADHD in U.S. children; these associations were stronger in boys than in girls. Considering the widespread use of BPA and growing literature on neurobehavioral effects of BPA in children, further study is warranted to determine if reducing exposure to BPA may represent an important avenue for ADHD prevention.
Background:
Early life exposure to the endocrine disruptor bisphenol A (BPA) may contribute to development of obesity. Prospective evidence in humans on this topic is limited.
Objectives:
We examined prenatal and early childhood BPA exposures in relation to childhood measures of adiposity in the Columbia Center for Children’s Environmental Health (CCCEH) New York City birth cohort.
Methods:
BPA concentrations were measured in prenatal (n=375) and child ages 3 (n=408) and 5 years (n=518) spot urine samples. Childhood anthropometric and bioelectrical impedance outcomes included body mass index z-scores (BMIZ) at 5 and 7 years, and fat mass index (FMI), percent body fat (%BF), and waist circumference (WC) at 7 years. Associations were evaluated using multiple linear regression with continuous and tertile BPA concentrations.
Results:
Prenatal urinary BPA concentrations were positively associated with child age 7 FMI (beta=0.31 kg/m2, p-value=0.04, [95%CI 0.01, 0.60]), %BF (beta=0.79, p-value=0.04, [95%CI 0.03, 1.55]), and WC (beta=1.29 cm, p-value=0.01, [95%CI 0.29, 2.30]), but not BMIZ, or change in BMIZ between ages 5 and 7 years (all p-values > 0.1). FMI results were sex-specific. Child urinary BPA concentrations were not associated with child anthropometric outcomes (all p-values > 0.05).
Conclusions:
Analyses of the CCCEH longitudinal birth cohort found associations between prenatal urinary BPA concentrations and FMI, %BF and WC. Our results suggest that prenatal BPA exposure may contribute to developmental origins of adiposity. These findings are consistent with several prior studies, raising concern about the pervasiveness of BPA.
Poor, minorities carry the burden of fracking waste in South Texas
Wastewater disposal wells in southern Texas are disproportionately permitted in areas with higher proportions of people of color and residents living in poverty, a pattern known as “environmental injustice.” EIA.
Poor, heavily Hispanic neighborhoods shoulder a disproportionate fracking wastewater burden in Texas’ booming Eagle Ford
Chavel Lopez lives just a few miles north of Texas’ Eagle Ford—one of the many regions in the country recently given a makeover from the fracking industry. He said:
“I just have to drive a bit south and see the wells and the flames,”
For Lopez, rather than a booming industry, these are signs of yet another pollution burden for the region’s people of color. He said:
“We already had issues. Right here in San Antonio, fuel storage tanks were all located on the eastside, predominantly African American neighborhoods”. “For some of these Hispanic neighborhoods, they were already dealing with uranium mining impacts and now the fracking of oil and gas.”
And new evidence supports his fears: Poor and minority neighborhoods bear a disproportionate share of fracking wastewater wells in South Texas’ Eagle Ford play, according to a new study.
The findings add to growing evidence that politically marginalized black, Hispanic and poor communities carry more than their share of the nation’s energy waste burden. Fracking wastewater contains potentially harmful chemicals and metals, and has been linked to surface and groundwater contamination and earthquake spikes.
“It’s another example of the environmental racism throughout the country,”
said lead author Jill Johnston, an assistant professor at the University of Southern California’s Keck School of Medicine.
Industry representatives, however, called the study flawed, and said it provided no evidence that wastewater disposal is actually harming people in these communities.
Fracking, or hydraulic fracturing, is a process that uses horizontal drilling and high volume fluid injections to release oil and gas. Along with water, the injections contain sand and a mix of chemicals—some of which have been linked to cancer, hormone impacts, and reproductive problems.
It’s estimated that every well produces about five million liters of wastewater, which is eventually pumped into disposal wells.
After the Southwest Workers Union—where Lopez works as the labor coordinator—expressed concern about Eagle Ford fracking waste, Johnston and colleagues looked at the racial and economic makeup of residents where oil and gas disposal wells were permitted between 2007 and 2014 in the heavily fracked Eagle Ford area of Texas. The Eagle Ford covers 26 counties and has seen explosive growth as improvements in fracking technology opened the previously untappable reserves. Researchers estimated more than 1,000 new wastewater wells have been permitted in the area since 2007.
They found that—after controlling for population density—people in areas that were more than 80 percent minority were twice as likely to live near permitted wastewater wells than areas less than 20 percent minority.
Of the more than 217,000 minorities living less than three miles from a disposal well, 83 percent were Hispanic, according to the study published last month in the American Journal of Public Health.
One main concern with disposal wells is that wastewater will make it back to surface water or contaminate nearby groundwater, said Desiree Plant, an assistant professor of chemical and environmental engineering at Yale University who was not involved in the study.
A separate study published last month in the Journal of Exposure Science & Environmental Epidemiology reported, “hydraulic-fracturing fluids and wastewater from unconventional oil and natural gas development contain hundreds of substances with the potential to contaminate drinking water.” The authors discovered that many compounds found are linked to reproductive and development impacts.
“A lot of people there [Eagle Ford area] are reliant on groundwater, putting this all underground is jeopardizing water sources,”
Johnston said, adding that the additional truck traffic and other disposal infrastructure only adds to the burden.
Plant said some harmful pollutants such as benzene also can volatize from wastewater and taint the air near disposal wells.
In addition, oil and gas disposal wells are linked to earthquake spikes in states such as Oklahoma, Texas and Kansas. Injected wastewater flows into faults, decreasing the resistance to geologic processes that trigger earthquakes, said Justin Rubinstein, a USGS research geophysicist, in a lecture last summer.
The U.S. Geological Survey estimates that in the central and eastern U.S. from 1973 and 2008 there was an average of 21 earthquakes a year magnitude 3 and larger—that average jumped to 99 from 2009 to 2013, correlating with the fracking boom.
Texas is the nation’s number one oil and gas producer. It has more than 8,000 oil and gas wastewater disposal wells. The Railroad Commission of Texas oversees the wells but locations are chosen by disposal operators, said Ramona Nye, a spokesperson for the Commission.
Oil and gas representatives funneled questions to the Independent Petroleum Association of America’s outreach program called Energy in Depth. Spokesman Steve Everley first questioned via email whether the authors were using “using proximity to minorities as a media hook.”
“What the authors did was pick an area that is well known as a major oil and gas producing region, and has a very high Hispanic population, and then ‘discovered’ that oil and gas development is happening in areas with high Hispanic populations,”
he said in a follow-up email, adding that many heavily Hispanic counties in the Eagle Ford have had unemployment numbers fall over the past 5 years.
The authors didn’t examine siting decisions for disposal wells, Everley noted, which suggests, “that this was more about promoting a particular narrative—one that was probably crafted before any ‘data’ were collected.”
Johnston countered that they found fracking activity slightly more prevalent in white communities but wastewater wells more frequently in communities of color.
The study follows a pattern for U.S. energy waste.
Johnston and colleagues wrote that marginalized communities are often targeted “because of the perceived lack of political power and limited resources with which to challenge a permit.” Lopez said:
A new generation of chemicals added to furniture, building insulation and baby products like car seats to slow the spread of flames are escaping into air at higher levels than previously thought, according to a new study out of Washington state.
The findings come as Washington lawmakers decide on bolstering flame retardant bans. The state was one of the first to ban an earlier generation of retardants, known as PBDEs.
The new research found flame retardant chemicals used to replace polybrominated diphenyl ethers (PBDEs) also escape, are ubiquitous in indoor air and suggest inhalation is a major route of exposure for people.
The compounds, called chlorinated organophosphate flame retardants, found in the study have been linked to cancer and reproductive problems, and some can alter hormones essential for development.
“We’ve been underestimating what total exposure is”
said Erika Schreder, staff scientist at the Washington Toxics Coalition and lead author of the study published this month in the scientific journal Chemosphere.
Researchers gave 10 people from Washington state an air sampler that simulates breathing to wear during a normal day: office work, commuting, hanging out at home. They tested for a suite of the new generation of chlorinated flame retardants and found all 10 were breathing some amount of them throughout the day.
Exposure to one of the most prevalent compounds was up to 30 times greater than ingesting the chemicals via dust. The distinction is important: dust exposure occurs largely through the mouth, previously thought to be the major exposure route for banned PBDEs.
“With PBDEs, inhalation wasn’t considered as important,” Inhalation of PBDEs accounted for between 10 and 20 percent of exposure, “With the replacements, we see quite a different picture.”
said Amina Salamova, an environmental chemist and researcher at Indiana University Bloomington who studies toxic pollutants.
Chlorinated flame retardants are used mostly in polyurethane foam, often in building insulation and everyday products such as furniture, children’s car seats and baby strollers. The compounds are substitutes for PBDEs, which were widely used as flame retardants until scientists reported they were building up in people and wildlife and various bans took hold.
The American Chemistry Council, which represents chemical manufacturers, has long maintained flame retardant chemicals are necessary to prevent fires and protect people. In response to the recent study, Bryan Goodman, director of product communications for the council, said in an email that
exposure via ingestion and inhalation is “anticipated and regulators generally take this into account” when assessing the risk of chemicals.
However, Salamova, who was not involved in the recent study, said the inhalation concerns raised by Schreder’s study were especially alarming and novel because it was levels of really small particles that were quite high. She said:
“These really go all the way down your air tract and penetrate into the lung tissue,”
While chlorinated flame retardants have been around for decades, Salamova said scientists have recently started to understand them as, at first, it was thought they weren’t harmful or able to accumulate in people and wildlife. However there is evidence the replacement are following the same path as PBDEs: chlorinated flame retardants have been found in household dust, children’s products, drinking water, and mother-toddlers pairs.
Washington state legislators introduced bills in the state House and Senate to ban five flame retardants from furniture and children’s products, which would also set up a system to make sure new replacements are safe. The bill includes flame retardants found in the air in the recent study. The House bill will have a hearing this Wednesday.
Erika Schreder, study lead author, said:
The study doesn’t give us the final answer on exposure, but it does offer “a good indication of the range” that people are exposed to.
Eighty-five percent of male smallmouth bass tested in or nearby 19 National Wildlife Refuges in the U.S. Northeast had signs of female reproductive parts, according to a new federal study.
The study, led by the U.S. Geological Survey and U.S. Fish and Wildlife Service, also reported that 27 percent of male largemouth bass in the testing sites were intersex.
The study is the first of its kind in National Wildlife Refuges and adds to growing evidence that endocrine disrupting chemicals are getting into U.S. lakes, rivers, streams and reservoirs—no matter how protected the waters seem. And such contamination seems to affect the reproductive development of some fish species, which can lead to threatened populations.
For the bass in this study, those considered “intersex” either had a protein that is used to make egg yolk typically found in females, or immature egg cells in their testes, said co author Fred Pinkney, a biologist with the U.S. Fisheries and Wildlife.
The eggs were in the very, very early stages
But any change to fish reproductive systems could possibly threaten overall fish populations and ability to properly reproduce.
During the fall seasons of 2008 to 2010, the researchers tested a total of 118 male smallmouth bass from 12 locations and 85 percent were intersex. They tested an additional 173 male largemouth bass from 27 sampling sites and 27 percent were intersex.
It’s not entirely clear why the bass were intersex as the researchers did not test the waters for specific chemicals, said lead author Luke Iwanowicz, a research biologist with the U.S. Geological Survey.
However, the suspected culprits of the sex changes are endocrine disrupting compounds.
This includes hormones, industrial chemicals and pesticides that are or mimic estrogen hormones. These compounds enter rivers and streams via permitted effluents, stormwater and agricultural runoff, and wastewater treatment plants, where excreted birth control and natural estrogens pass through relatively un-altered.
The study is just the latest to find intersex fish in U.S. waterways and builds on a U.S. Geological Survey study in 2009 that showed intersex male fish in nine U.S. river basins, though that study didn’t include Northeast basins. The bass tested in the Northeast waterways had a higher prevalence of intersex than the fish in the 2009 study.
It seems that certain fish species may be more sensitive to estrogenic compounds than others, as evidenced by the disparity between largemouth and smallmouth bass in this study. Previous studies also have reported that smallmouth bass seem more susceptible to intersex changes.
However it’s not clear if this is actual physical sensitivity to the chemicals or if it’s due to some species spending more time in more contaminated habitats.
National Wildlife Refuges are areas protected by the U.S. Fish and Wildlife Service. There are more than 560 such refuges nationally.
The U.S. Fish and Wildlife Service encourages management actions that reduce runoff into streams, ponds and lakes—both on and off of refuge lands
The national refuges tested spanned from eastern Ohio up to Maine and included: the Patuxent Research, Susquehanna, Montezuma, Great Swamp, Wallkill River, Great Meadows, Assabet River, Rappahannock River Valley, Mason Neck, Back Bay, John Heinz, Erie, Cherry Valley, Great Bay, Lake Umbagog, Sunkhaze Meadows, Missisquoi, Moosehorn and Ohio River Islands refuges.
Pinkney said the bass indicate that many aquatic species in Northeast U.S. refuges may be exposed to estrogenic chemicals.
Virginia Tech study finds common household chemicals affect reproduction in mice
Cleaning your bathroom? Along with killing germs some products could also be doing a number on sperm production and ovulation . Common ingredients in the cleaning sprays for your kitchen and bathroom make mice less fertile, suggesting the compounds could do the same to humans.
2014 Study Abstract
Alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC) are common ingredients in household bathroom and kitchen cleaning sprays. ADBAC+DDAC cause reproductive toxicity in mice. The aim of the present study was to investigate gender-specific reproductive effects from ADBAC+DDAC. Female reproduction was assessed through ovulation, oocyte implantation, and estrus cycling. Male reproductive function was assessed by sperm concentration, motility, and viability. Numbers of corpora lutea were not different after 2 weeks, but decreased after 8 weeks of ADBAC+DDAC exposure. Dams exposed for 5 weeks to ADBAC+DDAC spent significantly less time in estrus. ADBAC+DDAC exposed males exhibited declines in both sperm concentration and motility, but not sperm viability. Subfertility in mice from ADBAC+DDAC exposure is, therefore, mediated through reproductive disturbances in both females and males. While the effect of ADBAC+DDAC exposure on human health is unclear, widespread exposure necessitates further consideration of their potential reproductive toxicity.
Sources and More Information
Germ-killing bathroom sprays appear to weaken fertility, Environmental Health News, November 12, 2015.
Quaternary Ammonium Disinfectants Cause Subfertility in Mice by Targeting both Male and Female Reproductive Processes, sciencedirect, doi:10.1016/j.reprotox.2015.10.006, 12 November 2015.
Virginia Tech study finds common household chemicals affect reproduction in mice, vtnews, Aug. 14, 2014
Men exposed to certain banned but long-lived chemicals at high levels as teenagers are more likely to have defective sperm later in life. A study of men from the Faroe Islands finds that high DDT and PCB exposure during adolescence and adulthood is associated with abnormal chromosomes in sperm. Reunion by Hans Juul Hansen.
2015 Study abstract
Background:
While it is known that sperm aneuploidy contributes to early pregnancy losses and congenital abnormalities, causes are unknown and environmental contaminants are suspected.
Objectives:
Our goal was to evaluate associations between lifetime exposure to organochlorines, specifically dichlorodiphenyldicholorethylene (p,p’-DDE) and polychlorinated biphenyls (PCBs) and sperm aneuploidy in men from the general population of the Faroe Islands, a population with a known history of organochlorine exposures.
Methods:
Serum and semen samples from men (n=90) ages 22-44 participating in Faroe Islands health studies were analyzed for p,p’-DDE and PCB (118, 138, 153, and 180) and adjusted for total lipids. Cord blood and age 14 serum were available for a subgroup (n=40) and also analyzed for p,p’-DDE and PCBs. Sperm fluorescence in situ hybridization (FISH) for chromosome X, Y, and 18 was used to determine rates of XX18, XY18, YY18 and total disomy. Multivariable adjusted Poisson models were used to estimate the relation between organochlorine exposure and sperm disomy outcomes.
Results:
Adult p,p’-DDE and total PCB serum concentrations were each associated with significantly increased rates of XX18, XY18 and total disomy. Age 14 p,p’-DDE and PCB concentrations were each associated with significantly increased rates of XX, XY and total disomy at adult age. Associations between cord blood concentrations of p,p’-DDE and PCBs and sperm disomy at adult age were not consistently significant.
Conclusions:
Organochlorine exposures measured at age 14 and in adulthood were associated with sperm disomy in this sample of high exposure men, suggesting the impacts of persistent pollutants on testicular maturation and function need deeper investigation.
Sources and more information
DDT’s long shadow: Long-banned chemicals linked to abnormal sperm, Environmental Health News, November 4, 2015.
Sperm Aneuploidy in Faroese Men with Lifetime Exposure to Dichlorodiphenyldichloroethylene (DDE) and Polychlorinated Biphenyl (PCB) Pollutants, Environmental Health Perspectives; DOI:10.1289/ehp.1509779, 4 November 2015.
Girls born to mothers with high levels of BPA in their system during the first trimester of pregnancy weigh less at birth than babies with lower exposure, according to a new study.
2015 Study Abstract
Context and Objective:
Effects of prenatal exposure to Bisphenol A (BPA) on gestational and birth outcomes are controversial. The aim of the study was to evaluate the relationship between prenatal exposure to BPA and birth and gestational outcomes.
Design, Setting, Participants, and Outcome:
Levels of unconjugated (uBPA) and BPA glucuronide in 80 matching samples of pregnant women during the first trimester of pregnancy and at delivery and matching term cord blood obtained from a prospective study conducted at the University of Michigan Hospitals were determined using a methodology validated in the National Institutes of Environmental Health Sciences funded Round Robin study and related to pregnancy outcomes.
Results:
Highest levels of uBPA were found in maternal term samples followed by first trimester maternal (M1) samples and cord blood. A 2-fold increase in M1 uBPA was associated with 55-g less birth weight when male and female pregnancies were combined and 183-g less birth weight with only female pregnancies. A 2-fold increase in maternal term uBPA was associated with an increased gestational length of 0.7 days for all pregnancies and 1.1 days for only female pregnancies.
Conclusion:
Higher uBPA exposure levels during first trimester and term are associated with sex-specific reduction in birth weight and increase in gestational length, respectively. Race, parity, and employment have an effect on BPA exposure. Because low birth weight is associated with adverse health outcomes, effect of early pregnancy BPA levels on reducing birth weight highlights the risk posed by developmental exposure to BPA.
Sources and more information
Gender-Specific Effects on Gestational Length and Birth Weight by Early Pregnancy BPA Exposure, Endocrine Society, DOI: http://dx.doi.org/10.1210/jc.2015-1724, September 25, 2015.
Pregnant women with high levels of BPA in their blood during their first trimester were more likely to have baby girls with low birth weights,Environmental Health Sciences, September 25, 2015.
Chemicals may alter placenta genes, threaten fetuses
Researchers link endocrine disrupting chemical exposure to altered gene function in pregnant women’s placentas, which could hamper fetal growth. A Spritz of Perfume image by Jennuine Captures Photography.
Women exposed to widely used chemicals while pregnant are more likely to have altered gene function in their placentas, according to a new study.
2015 Study Abstract
Background:
There is increasing concern that early-life exposure to endocrine-disrupting chemicals (EDCs) can influence the risk of disease development. Phthalates and phenols are two classes of suspected EDCs that are used in a variety of everyday consumer products, including plastics, epoxy resins, and cosmetics. In utero exposure to EDCs may impact disease propensity through epigenetic mechanisms.
Objective:
The objective of this study was to determine if prenatal exposure to multiple EDCs is associated with changes in miRNA expression of human placenta, and if miRNA alterations are associated with birth outcomes.
Methods:
Our study was restricted to a total of 179 women co-enrolled in the Harvard Epigenetic Birth Cohort and the Predictors of Preeclampsia Study. We analyzed associations between first-trimester urine concentrations of 8 phenols and 11 phthalate metabolites and expression of 29 candidate miRNAs in placenta by qRT-PCR.
Results:
For three miRNAs, miR-142-3p, miR15a-5p, and miR-185, we detected associations between ∑phthalates or ∑phenols on expression levels (p<0.05). By assessing gene ontology enrichment, we determined the potential mRNA targets of these microRNAs predicted in silico were associated with several biological pathways, including the regulation of protein serine/threonine kinase activity. Four gene ontology biological processes were enriched among genes significantly correlated with the expression of miRNAs associated with EDC burden.
Conclusions:
Overall, these results suggest that prenatal phenol and phthalate exposure is associated with altered miRNA expression in placenta, suggesting a potential mechanism of EDC toxicity in humans.
Sources and more information
First-Trimester Urine Concentrations of Phthalate Metabolites and Phenols and Placenta miRNA Expression in a Cohort of U.S. Women, Environ Health Perspect; DOI:10.1289/ehp.1408409, 19 June 2015.
Boys born to mothers living and working around endocrine disrupting chemicals are more likely to have a urethra on the underside of the penis, rather than at the tip, based on a French study. One heart image by Stefano Corso.
Genital defect in baby boys linked to moms’ chemical exposure
Mothers around a lot of endocrine disrupting chemicals at home or in jobs such as cleaners, hairdressers and laboratory workers during pregnancy are more likely to have baby boys with a genital defect, according to a new study in the south of France.
The study adds to mounting evidence that fetal exposure to chemicals that mimic people’s natural hormones may cause hypospadias, a condition where the opening of the urethra is on the underside of the penis rather than at the tip.
French researchers examined more than 600 children in the south of France and found that babies exposed to endocrine disrupting chemicals while their genitals were developing were more likely to suffer from hypospadias.
Half the boys had hypospadias and half did not. The risk for those exposed was 68 percent higher than the unexposed boys. The researchers ruled out baby boys with known genetic risks for such defects.
“This study is well-crafted and supports the thought that chemicals in the environment are affecting our genital well-being,”
said Dr. George Steinhardt, a pediatric urologist at the Helen DeVos Children’s Hospital in Grand Rapids, Michigan, who was not involved in the study. He added
“This is another little piece of the puzzle that says we are affected by these exposures,”
The defect, which can be minor or quite severe depending on how far the opening is from the tip, can lead to problems with urination and, later in life, sexual difficulty.
About 70 percent of deformities are relatively mild, Steinhardt said.
It is one of the most common genital defects in baby boys, and most cases require surgery, often done before they reach two years old. In the United States, an estimated five out of 1,000 boys are born annually with hypospadias, while Europe’s rate is slightly less than two out of 1,000.
The researchers estimated the unborn babies’ exposure by looking at their parents’ jobs and where they lived. Working with hormone disrupting chemicals and living in homes near heavy polluters were both linked to more baby boys having the defect. However, the researchers did say a limit of the study was attempting to estimate fetal exposure to such chemicals.
Mothers were most likely to have boys with hypospadias if they worked as a cleaner, hairdresser or beautician.
Some of the endocrine disrupting chemicals linked to the professions involved in the study were bisphenol-A (BPA), phthalates, polychlorinated compounds, alkylphenolic compounds and organic solvents.
Most exposures—78 percent—occurred in the window of development when babies’ genitals are forming.
“We found that fetal exposure to [endocrine disrupting chemicals] was a significant risk factor for hypospadias in our series. The types of substance having an impact on the phenotype were heterogeneous, but detergents, pesticides, and cosmetics accounted for 75 percent of the cases,”
the authors wrote in the study published in the European Urology journal this month.
The authors were not available for an interview.
The study doesn’t prove that the exposure caused hypospadias, as chemical exposure isn’t the only possible cause. However, it is plausible since such chemicals impact the developing endocrine system,
said Dr. Laurence Baskin, professor of urology and chief of pediatric urology at University of California, San Francisco, who added that it would be most likely due to a disruption in the boys’ androgen hormones while their penis was developing.
Other possible causes of the birth defect include older, obese mothers, and fertility or hormone treatments during pregnancy, according to the U.S. Centers for Disease Control and Prevention.
In reviewing potential causes of hypospadias, European and Australian pediatric researchers found that “having an affected family member is the highest identified risk factor so far.” In the European and Australian researchers’ report, which examined recent science of hypospadias causes, they also concluded that mothers’ chemical exposure might also cause the defects or raise the risk for those boys already predisposed through their genes.
One of the major strengths of the current study was the exclusion of a lot of children with known genetic risk factors for hypospadias, Baskin said.
“It’s an outstanding study with both age and culturally matched children,”
Baskin said.
This wasn’t the first time scientists have found a link between certain chemicals and hypospadias. Mothers in southeast England who were heavily exposed to endocrine disrupting phthalates on the job were about three times as likely to have a baby boy with hypospadias. Phthalates are used in some cosmetics, fragrances, food packaging and PVC plastics.
In 2010, Italian researchers found that among 160 mothers, those who worked with more than one group of endocrine disrupting chemicals were four times as likely to have a baby boy with hypospadias.
Baskin said the French study could help stem hypospadias prevalence. He added :
“Nobody dies from hypospadias, most are cured with surgery, but if we can come up with some kind of prevention protocol, it could prevent a lot of surgeries and anxiety for families,”
For questions or feedback about this piece, contact Brian Bienkowski.
A DES Daughter's Blog 